Old page wikitext, before the edit (old_wikitext) | '{{Good article}}
{{Use mdy dates|date=March 2017}}
{{Use American English|date=December 2013}}
{{Infobox project
| name = SpaceX reusable launch system development program
| logo =
| image = File:ORBCOMM-2 (23282658734).jpg
| caption = [[Falcon 9 Flight 20]]'s first stage landing vertically on solid ground in December 2015
| website = <!-- {{URL|example.com}} -->
| mission_statement =
| commercial = Yes
| type = Privately funded technology development
| products = [[Falcon 9]], [[Falcon Heavy]], [[Interplanetary Transport System]]
| location = Various
| owner = [[SpaceX]]
| founder = [[Elon Musk]]
| funding =
| established = Publicly announced 2011
| disestablished = <!-- {{End date|YYYY|MM|DD}} -->
| current_status = Active
}}
The '''SpaceX reusable launch system development program''' is a [[private spaceflight|privately funded]] program to develop a set of new technologies for an [[Orbital spaceflight|orbital]] [[spacecraft|launch system]] that may be [[reusable launch vehicle|reused]] many times in a manner similar to the reusability of [[aircraft]]. The company [[SpaceX]] is developing the technologies over a number of years to facilitate full and rapid reusability of space [[launch vehicle]]s. The project's long-term objectives include returning a launch vehicle [[multistage rocket|first stage]] to the launch site in minutes and to return a second stage to the [[launch pad]] following orbital realignment with the launch site and [[atmospheric entry|atmospheric reentry]] in up to 24 hours. SpaceX's long term goal is that both stages of their orbital launch vehicle<!-- they are only working on the first stage with the Falcon 9; will do both stages of the Mars Colonial Transporter --> will be designed to allow reuse a few hours after return.<ref name="pm20120207">{{cite news |url=http://www.popularmechanics.com/science/space/rockets/elon-musk-on-spacexs-reusable-rocket-plans-6653023 |title=Elon Musk on SpaceX's Reusable Rocket Plans |work=Popular Mechanics |last=Simberg |first=Rand |date=February 8, 2012 |accessdate=February 7, 2012}}</ref>
The program was publicly announced in 2011. SpaceX first achieved a [[Falcon 9 Flight 20|successful landing and recovery of a first stage]] in December 2015. The [[SES-10|first re-flight of a landed first stage]] occurred in March 2017<ref name=sn20170330/> with the second occurring in June 2017, that one only five months after the maiden flight of the booster.<ref name=sir-20170626 /> The third attempt occurred in October 2017 with the [[SES-11]]/[[EchoStar-105]] mission. Second flights of refurbished first stages then became routine.
The [[reusable launch system]] technology was developed and initially used for the first stages of the [[Falcon (rocket family)|Falcon family]] of rockets.<ref name=sn20141024/> After stage [[Separation event|separation]], the return process involves flipping the booster around, an optional boostback burn to reverse its course, a reentry burn, controlling direction to arrive at the landing site and a landing burn to effect the final low-altitude deceleration and touchdown.
SpaceX is intending to develop technology to extend reusable flight hardware to second stages, a more challenging engineering problem because the vehicle is travelling at [[Orbital speed#Tangential velocities at altitude|orbital velocity]],<ref name=nsf20160927/><ref name=sn20141024/><ref name=nsf20140307/>
which is considered paramount to the plans Elon Musk is championing to enable the [[Colonization of Mars|settlement of Mars]]. It is thus planned to be developed for all of the flight hardware for the new SpaceX vehicles planned to transit to Mars,<ref name=gq20151212/><ref name=spacex-itspresentation201609/> with initial test flights expected no earlier than 2020.<ref name=nsf20160927/> SpaceX may also experiment with second stage recovery on a few select Falcon 9 flights<ref name=issR&Dconf20170719-14:15/> or Falcon Heavy flights.<ref name=musk20170331>
{{cite web |url=https://twitter.com/elonmusk/status/847882289581359104 |title=Considering trying to bring upper stage back on Falcon Heavy demo flight for full reusability |last=Musk|first=Elon |publisher=SpaceX |date=2017-03-31 }}</ref>
{{TOC limit|4}}
== History ==
[[File:Falcon rocket family4.svg|thumb|400px|right|From left to right, [[Falcon 1]], [[Falcon 9 v1.0]], three versions of [[Falcon 9 v1.1]], three versions of [[Falcon 9 Full Thrust|Falcon 9 v1.2 (Full Thrust)]], and [[Falcon Heavy]]. The SpaceX reusable rocket technology is being developed for both Falcon 9 v1.2 and Falcon Heavy.]]
SpaceX initially attempted to land the first stage of the [[Falcon 1#Reusability|Falcon 1 by parachute]], however the stage did not survive the re-entry into the atmosphere. They continued to experiment with parachutes on the earliest [[Falcon 9]] flights after 2010. SpaceX subsequently switched its focus to developing a powered descent landing system.<ref name=nsf20170330>
{{cite news |last=Graham|first=William |url=https://www.nasaspaceflight.com/2017/03/spacex-historic-falcon-9-re-flight-ses-10/ |title=SpaceX conducts historic Falcon 9 re-flight with SES-10 – Lands booster again |work=[[NASASpaceFlight.com]] |date=2017-03-30 |accessdate=2017-05-27 |quote='The earliest Falcon 9 launches carried parachutes which were to have been used to recover the first stage. However, this was abandoned due to the stage disintegrating during reentry, before the parachutes could be deployed. Instead, SpaceX began to investigate using the stage’s engines to make a powered descent and landing. Alongside this, an improved Falcon 9 vehicle, the Falcon 9 v1.1, was developed.' }}</ref>
The broad outline of the reusable launch system was first publicly described in September 2011. SpaceX said it would attempt to develop powered descent and recovery of both Falcon 9 stages{{mdash}}a fully vertical takeoff, vertical landing ([[VTVL]]) rocket. The company produced a [[Computer animation|computer-animated video]] depicting a notional view of the first stage returning tail-first for a powered descent and the second stage with a heat shield, reentering head first before rotating for a powered descent.<ref name="wp20110929">{{cite video |url=https://www.youtube.com/watch?v=RkvLQdzZRFo |title=SpaceX Chief Details Reusable Rocket |agency=Associated Press |work=Washington Post |date=September 29, 2011 |accessdate=April 9, 2016}}</ref><ref name="sdc20110930">{{cite news |url=http://www.space.com/13140-spacex-private-reusable-rocket-elon-musk.html |title=SpaceX Unveils Plan for World's First Fully Reusable Rocket |newspaper=Space.com |last=Wall |first=Mike |date=September 30, 2011 |accessdate=October 11, 2011}}</ref><ref name="SpaceX Video from SpaceX. com">{{cite web |url=http://www.spacex.com/assets/video/spacex-rtls-green.mp4 |title=Falcon 9 Return to Launch Site |format=video |work=SpaceX.com |archiveurl=https://web.archive.org/web/20111011221641/http://www.spacex.com/assets/video/spacex-rtls-green.mp4 |archivedate=October 11, 2011}}</ref><ref name="npc20110929">{{cite AV media |url=https://www.youtube.com/watch?v=xrVD3tcVWTY |title=National Press Club: The Future of Human Spaceflight |medium=video |work=NPC video repository |date=September 29, 2011 |people=Mark Hamrick, Elon Musk |publisher=National Press Club |quote=(@18:15 It is a very tough engineering problem—and it wasn't something that I thought, wasn't sure it could be solved for a while. But then, just relatively recently, in the last 12 months or so, I've come to the conclusion that it can be solved. And SpaceX is going to try to do it. Now, we could fail. I am not saying we are certain of success here, but we are going to try to do it. And we have a design that, on paper, doing the calculations, doing the simulations, it does work. Now we need to make sure that those simulations and reality agree, because generally when they don't, reality wins. So that's to be determined.)}}</ref><!-- ←the original source was http://www.c-span.org/Events/National-Press-Club-The-Future-of-Human-Spaceflight/10737424486/ |title=National Press Club: The Future of Human Spaceflight |work=C-SPAN.org |date=September 29, 2011 --- but that link has gone dead. Found another copy on the NPC video repository on YouTube --> In September 2012, SpaceX began flight tests on a prototype reusable first stage with the suborbital [[Grasshopper (rocket)|Grasshopper rocket]].<ref name="cl20121224" /> Those tests continued into 2014, including testing of a second and larger prototype vehicle, [[F9R Dev1]].
News of the Grasshopper test rocket had become public a few days earlier, when the [[Federal Aviation Administration|US Federal Aviation Administration]] released a [[National Environmental Policy Act|draft Environmental Impact Assessment]] for the SpaceX Test Site in Texas, and the space media had reported it.<ref name="faa20110922">{{cite web |url=http://www.faa.gov/about/office_org/headquarters_offices/ast/media/20110922%20spacex%20grasshopper%20draft%20ea.final.pdf |title=Draft Environmental Assessment for Issuing an Experimental Permit to SpaceX for Operation of the Grasshopper Vehicle at the McGregor Test Site, Texas |publisher=Federal Aviation Administration |date=September 22, 2011 |accessdate=November 21, 2013}}</ref><ref name="satspot20110926" /> In May 2012, SpaceX obtained a set of atmospheric test data for the recovery of the Falcon 9 first stage based on 176 test runs in the [[NASA]] [[Marshall Space Flight Center]] [[wind tunnel]] test facility. The work was contracted for by SpaceX under a reimburseable [[Space Act Agreement]] with NASA.<ref name="sn20120528">{{cite news |url=http://www.spacenews.com/article/nasa-finishes-wind-tunnel-testing-falcon-9-1st-stage |title=NASA Finishes Wind-tunnel Testing of Falcon 9 1st Stage |work=Space News |date=May 28, 2012 |accessdate=June 26, 2012}}</ref>
In 2012, it was projected that the first-stage separation of a [[Falcon 9R|reusable Falcon 9]] rocket would occur at a velocity of approximately {{nowrap|2.0 km/s}} {{nowrap|(6,500 km/h; 4,100 mph; Mach 6)}} rather than the {{nowrap|3.4 km/s}} {{nowrap|(11,000 km/h; 7,000 mph; Mach 10)}} for an expendable Falcon 9, to provide the residual fuel necessary for the deceleration and turnaround maneuver and the controlled descent and landing.<ref name="pm20120207" />
In November 2012, CEO [[Elon Musk]] announced SpaceX's plans to build a second, much larger, [[SpaceX super-heavy lift launch vehicle|reusable rocket system]], this one to be powered by [[LOX]]/[[liquid methane|methane]] rather than LOX/[[RP-1]] used on Falcon 9 and Falcon Heavy. The new system was to be "an evolution of SpaceX's Falcon 9 booster", and SpaceX reiterated their commitment to develop a breakthrough in vertical landing technology.<ref name="sdc20121123">{{cite news |url=http://www.space.com/18596-mars-colony-spacex-elon-musk.html |title=Huge Mars Colony Eyed by SpaceX Founder Elon Musk |work=Space.com |last=Coppinger |first=Rod |date=November 23, 2012 |accessdate=November 25, 2012 |quote=much bigger [than Falcon 9], but I don’t think we’re quite ready to state the payload. We’ll speak about that next year.}}</ref> By the end of 2012, the demonstration test vehicle, Grasshopper, had made three VTVL test flights{{mdash}}including a 29-second hover flight to {{convert|40|m|sp=us}} on December 17, 2012.<ref name="cl20121224">{{cite news |url=http://cosmiclog.nbcnews.com/_news/2012/12/23/16114180-spacex-launches-its-grasshopper-rocket-on-12-story-high-hop-in-texas |title=SpaceX launches its Grasshopper rocket on 12-story-high hop in Texas |work=NBC News{{\}}Cosmic Log |last=Boyle |first=Alan |date=December 24, 2012 |accessdate=December 25, 2012}}</ref> In early March 2013, SpaceX successfully tested Grasshopper for a fourth time when it flew to an altitude of over {{convert|80|m|sp=us}}.<ref name=nsj20130309/>
In March 2013, SpaceX announced that it would instrument and equip subsequent Falcon 9 first-stages as controlled descent test vehicles, with plans for over-water propulsively-decelerated simulated landings beginning in 2013, with the intent to return the vehicle to the launch site for a powered landing{{mdash}}possibly as early as mid-2014.<ref name="pa20130328">{{cite news |url=http://www.parabolicarc.com/2013/03/28/dragon-post-mission-press-conference-notes/ |title=Dragon Post-Mission Press Conference Notes |work=Parabolic Arc |last=Messier |first=Doug |date=March 28, 2013 |accessdate=March 30, 2013 |quote=Q. What is strategy on booster recover? Musk: Initial recovery test will be a water landing. First stage continue in ballistic arc and execute a velocity reduction burn before it enters atmosphere to lessen impact. Right before splashdown, will light up the engine again. Emphasizes that we don’t expect success in the first several attempts. Hopefully next year with more experience and data, we should be able to return the first stage to the launch site and do a propulsion landing on land using legs. Q. Is there a flight identified for return to launch site of the booster? Musk: No. Will probably be the middle of next year.}}</ref> The April 2013 draft [[Environmental impact statement|Environmental Impact Statement]] for the proposed [[SpaceX South Texas Launch Site]] includes specific accommodations for return of the Falcon 9 first-stage boosters to the launch site.<ref name="faa201304v1">{{cite report|url=http://1.usa.gov/YtxBzo |title=Draft Environmental Impact Statement: SpaceX Texas Launch Site |publisher=Federal Aviation Administration{{\}}Office of Commercial Space Transportation |last=Nield |first=George C. |volume=1 |date=April 2013 |deadurl=yes |archiveurl=https://web.archive.org/web/20131207085028/http://www.faa.gov/about/office_org/headquarters_offices/ast/environmental/nepa_docs/review/documents_progress/spacex_texas_launch_site_environmental_impact_statement/media/SpaceX_Texas_Launch_Site_Draft_EIS_V1.pdf |archivedate=December 7, 2013 |df= }}</ref> Elon Musk first publicly referred to the reusable Falcon 9 as the [[Falcon 9-R]] in April 2013.<ref name="musk20130428" />
In September 2013, SpaceX successfully relit three engines of a spent booster on an orbital launch, and the booster re-entered the atmosphere at hypersonic speed without burning up.<ref name=fp20131209/> With the data collected from the first flight test of a booster-controlled descent from high altitude, coupled with the technological advancements made on the Grasshopper low-altitude landing demonstrator, SpaceX announced it believed it was ready to test a full land-recovery of a booster stage.<ref name=pm20130930/> Based on the positive results from the first high-altitude flight test, SpaceX advanced the expected date of a test from mid-2014 to early 2015{{clarify|date=September 2016}}, with the intention of doing so on the [[SpaceX CRS-3|next Space Station cargo resupply flight]] pending regulatory approvals.<ref name="bbc20130930" /><ref name="pa20130930" /> That flight took place on April 18, 2014.<ref name=aw20140428a>{{cite news |last=Norris |first=Guy |title=SpaceX Plans For Multiple Reusable Booster Tests |url=http://aviationweek.com/space/spacex-plans-multiple-reusable-booster-tests |accessdate=May 17, 2014 |newspaper=Aviation Week |date=April 28, 2014 |quote=The April 17 F9R Dev 1 flight, which lasted under 1 min., was the first vertical landing test of a production-representative recoverable Falcon 9 v1.1 first stage, while the April 18 cargo flight to the ISS was the first opportunity for SpaceX to evaluate the design of foldable landing legs and upgraded thrusters that control the stage during its initial descent.}}</ref><ref name="ut20140419">{{cite news |url=http://www.universetoday.com/111377/spacex-makes-strides-towards-1st-stage-falcon-rocket-recovery-during-space-station-launch/ |title=SpaceX Makes Strides Towards 1st Stage Falcon Rocket Recovery during Space Station Launch |work=Universe Today |last=Kremer |first=Ken |date=April 19, 2014 |accessdate=April 19, 2014}}</ref>
Musk stated in May 2013 that the goal of the program is to achieve full and rapid reusability of the first stage by 2015, and to develop full launch vehicle reusability following that as "part of a future design architecture".<ref name="atd20130530">{{cite AV media |url=http://allthingsd.com/20130530/tesla-ceo-and-spacex-founder-elon-musk-the-full-d11-interview-video/ |title=Tesla CEO and SpaceX Founder Elon Musk: The Full D11 Interview (Video) |work=All Things D |last=Gannes |first=Liz |medium=Video interview |section=36:03 |date=May 30, 2013 |accessdate=May 31, 2013 |quote=hopeful that sometime in the next couple of years we'll be able to achieve full and rapid reusability of the first stage—which is about three-quarters of the cost of the rocket—and then with a future design architecture, achieve full reusability. }}</ref>
In February 2014, SpaceX made explicit that the newly defined super-heavy [[ITS launch vehicle|launch vehicle]] for what was then called [[Interplanetary Transport System|Mars Colonial Transporter]] would also make use of the reusable technology.<ref name=nsf20140307>{{cite news |last=Belluscio |first=Alejandro G. |title=SpaceX advances drive for Mars rocket via Raptor power |url=http://www.nasaspaceflight.com/2014/03/spacex-advances-drive-mars-rocket-raptor-power/ |accessdate=April 3, 2014 |newspaper=NASAspaceflight.com |date=March 7, 2014}}</ref>
This was consistent with Musk's strategic statement in 2012 that "The revolutionary breakthrough will come with rockets that are fully and rapidly reusable. We will never conquer [[Mars]] unless we do that. It'll be too expensive. The American colonies would never have been pioneered if the ships that crossed the ocean hadn't been reusable."<ref name=esquire20121115>{{cite news |last=Junod |first=Tom |title=Triumph of His Will |url=http://www.esquire.com/features/americans-2012/elon-musk-interview-1212 |accessdate=April 5, 2014 |newspaper=Esquire |date=November 15, 2012}}</ref>
Also in May 2014, SpaceX publicly announced an extensive test program for a related reusable technology: a propulsively-landed [[space capsule]] called ''[[DragonFly (rocket)|DragonFly]]''. The tests were to be run in Texas at the [[McGregor Rocket Test Facility]] in 2014–2015.<ref name=nbc20140521>{{cite news |last=Boyle |first=Alan |title=Elon Musk's SpaceX Plans DragonFly Landing Tests |url=http://www.nbcnews.com/science/space/elon-musks-spacex-plans-dragonfly-landing-tests-n111386 |accessdate=May 22, 2014 |newspaper=NBC News |date=May 21, 2014}}</ref>
In June 2014, [[Chief operating officer|COO]] [[Gwynne Shotwell]] clarified that all funding for [[new product development|development]] and [[validation and verification|testing]] of the reusable launch system technology development program is private funding from SpaceX, with no contribution by the [[Federal government of the United States|US government]].<ref name=AtlanticCouncil20140604>
{{cite AV media |url=https://www.youtube.com/watch?v=sYocHwhfFDc |title=Discussion with Gwynne Shotwell, President and COO, SpaceX |publisher=Atlantic Council |first=Gwynne |last=Shotwell |time=22:35–26:20 |date=June 4, 2014 |accessdate=June 9, 2014 |quote=''This technology element [reusable launch vehicle technology] all this innovation is being done by SpaceX alone, no one is paying us to do it. The government is very interested in the data we are collecting on this test series. ... This is the kind of thing that entrepreneurial investment and new entrants/innovators can do for an industry: fund their own improvements, both in the quality of their programs and the quality of their hardware, and the speed and cadence of their operations.''}}</ref>
<ref name=sfn20140606>{{cite news |last1=Clark |first1=Stephen |title=SpaceX to balance business realities, rocket innovation |url=http://www.spaceflightnow.com/news/n1406/06spacexmanifest/#.VAoLORaunr5 |accessdate=September 5, 2014 |publisher=Spaceflight Now |date=June 6, 2014 |quote=''SpaceX is using private capital to develop and demonstrate the Falcon 9 rocket's reusability. SpaceX has not disclosed how much the reusable rocket program will cost''}}</ref>
As of 2017 SpaceX had spent over a billion dollars on the development program.<ref>{{cite news |title=SpaceX flies rocket for second time in historic test of cost-cutting technology |url=https://spaceflightnow.com/2017/03/31/spacex-flies-rocket-for-second-time-in-historic-test-of-cost-cutting-technology/ |publisher=Spaceflight Now |first1=Stephen |last1=Clark |date=March 31, 2017 |accessdate=April 22, 2017 |quote=''Musk said SpaceX made the Falcon 9 rocket’s first stage reusable with entirely private funding, investing at least $1 billion in the effort [...]''}}</ref>
For the first time, SpaceX stated in July 2014 that they are "highly confident of being able to land successfully on a [[floating launch platform|floating launch pad]] or back at the launch site and refly the rocket with no required refurbishment."<ref name=sn20140721>
{{cite news |last1=Berger |first1=Brian |title=SpaceX Releases Footage of Falcon 9 First-stage Splashdown |url=http://www.spacenews.com/article/launch-report/41350spacex-releases-footage-of-falcon-9-first-stage-splashdown |accessdate=July 23, 2014 |publisher=SpaceNews |date=July 21, 2014}}</ref>
By late 2014, SpaceX suspended or abandoned the plan to recover and reuse the Falcon 9 second stage;<ref name=mit20141024>{{cite av media |url=https://www.youtube.com/watch?v=y13jbl7ASxY&t=14m20s |title=Elon Musk interview at MIT, October 2014 |date=October 24, 2014 |publisher= |via=YouTube}}</ref> the additional mass of the required heat shield, landing gear, and low-powered landing engines would incur too great a performance penalty.
In September 2016, SpaceX announced that development was underway to extend the reusable flight hardware to second stages, a more challenging engineering problem because the vehicle is travelling at [[Orbital speed#Tangential velocities at altitude|orbital velocity]]. The reusable technology was to have been extended to the 2016 designs of both the [[ITS tanker|tanker]] and [[Interplanetary Spaceship|crewed spaceship]] upper stage variants as well as the [[ITS booster|first stage]] of the [[ITS launch vehicle]] for the [[Interplanetary Transport System]],<ref name=nsf20160927>
{{cite news |last=Bergin |first=Chris |url=https://www.nasaspaceflight.com/2016/09/spacex-reveals-mars-game-changer-colonization-plan/ |title=SpaceX reveals ITS Mars game changer via colonization plan |work=[[NASASpaceFlight.com]] |date=September 27, 2016 |accessdate=October 16, 2016}}</ref><ref name=sn20141024>
{{cite news |last1=Foust |first1=Jeff |title=Next Falcon 9 Launch Could See First-stage Platform Landing |url=http://www.spacenews.com/article/launch-report/42305next-falcon-9-launch-could-see-first-stage-platform-landing |accessdate=October 25, 2014 |work=SpaceNews |date=October 25, 2014}}</ref><ref name=nsf20140307/>
and is considered paramount to the plans Elon Musk is championing to enable the [[Colonization of Mars|settlement of Mars]].<ref name=gq20151212>
{{cite news |last1=Heath |first1=Chris |title=How Elon Musk Plans on Reinventing the World (and Mars) |url=https://www.gq.com/story/elon-musk-mars-spacex-tesla-interview |accessdate=December 12, 2015 |work=GQ |date=December 12, 2015 |quote=''SpaceX exists to further [the vision of humans becoming multi-planetary] on several fronts: to develop the reusable rocket technology that would be needed to ferry large numbers of people, and large amounts of cargo, to Mars; ...''}}</ref><ref name="spacex-itsvideo201609-09:20">
{{cite AV media |people=Elon Musk |date=September 27, 2016 |title=Making Humans a Multiplanetary Species |trans-title= |medium=video |language= |url=https://www.youtube.com/watch?v=H7Uyfqi_TE8 |access-date=October 10, 2016 |format= |time=9:20–10:10 |location=IAC67, Guadalajara, Mexico |publisher=SpaceX |id= |isbn= |oclc= |quote=''So it is a bit tricky. Because we have to figure out how to improve the cost of the trips to Mars by five million percent ... translates to an improvement of approximately 4 1/2 orders of magnitude. These are the key elements that are needed in order to achieve a 4 1/2 order of magnitude improvement. Most of the improvement would come from full reusability—somewhere between 2 and 2 1/2 orders of magnitude—and then the other 2 orders of magnitude would come from refilling in orbit, propellant production on Mars, and choosing the right propellant.'' |ref= }}</ref><ref name=spacex-itspresentation201609>
{{cite web |url=http://www.spacex.com/sites/spacex/files/mars_presentation.pdf |publisher=[[SpaceX]] |title=Making Humans a Multiplanetary Species |date=September 27, 2016 |archive-url=https://web.archive.org/web/20160928040332/http://www.spacex.com/sites/spacex/files/mars_presentation.pdf |archive-date=September 28, 2016 |accessdate=October 16, 2016}}</ref> In 2016, initial test flights of an Interplanetary Transport System vehicle were expected no earlier than 2020.<ref name=nsf20160927/>
In 2017 SpaceX was making test flight progress in [[Iterative and incremental development|incrementally and iteratively]] developing a fairing recovery system.<ref name=verge20170330>
{{cite news |last1=Lopatto |first1=Elizabeth |title=SpaceX even landed the nose cone from its historic used Falcon 9 rocket launch |url=https://www.theverge.com/2017/3/30/15132314/spacex-launch-fairing-landing-falcon-9-thruster-parachutes |accessdate=31 March 2017 |work=[[The Verge]] |date=30 March 2017}}</ref><ref name=sn20170330>
{{cite news |last=Henry |first=Caleb |url=http://spacenews.com/spacex-demonstrates-rocket-reusability-with-ses-10-launch-and-booster-landing/ |title=SpaceX demonstrates reusability |date=March 30, 2017 |work=[[SpaceNews]] |accessdate=13 September 2017 }}</ref>
In July 2017, Musk said "we are quite close to being able to recover the fairing. ... We've got a decent shot of recovering a fairing by the end of the year, and reflight by late this year or early next."<ref name=issR&Dconf20170719-14:15>
{{cite AV media |people=Elon Musk |date=July 19, 2017 |title=Elon Musk, ISS R&D Conference |trans-title= |medium=video |language= |url=https://www.youtube.com/watch?v=BqvBhhTtUm4?t=852 |access-date=September 13, 2017 |format= |time=14:15–15:55 |location=ISS R&D Conference, Washington DC, USA |publisher= |id= |isbn= |oclc= |quote=''I think we are quite close to being able to recover the fairing. ... about a 5 or 6 million dollar piece fo equipment. We've got a decent shot of recovering a fairing by the end of the year, and reflight by late this year or early next. ... Upper stage is about 20 percent of the cost of the mission. So if you get boost stage and fairing we're around 80 percent reusable. ... Think for a lot of missions, we could even bring the second stage back. So were going to try to do that, but our primary focus [for the next couple of years will be crew Dragon].'' }}</ref>
The [[cost]] savings to SpaceX of recovering the fairing is expected to be on the order of {{USD|5 million}}. Together, the booster stage and the fairing make up approximately 80 percent of the cost of a launch.<ref name=issR&Dconf20170719-14:15/>
Despite 2014 plans to suspend development of Falcon 9 second stage reuse,<ref name=mit20141024/>
Musk further commented in July 2017 that a few experimental attempts would be made on particular future flights to bring a Falcon 9 second stage back.<ref name=issR&Dconf20170719-14:15/>
== Technologies ==
Several new technologies needed to be developed and tested to facilitate successful launch and recovery of both [[rocket stage|stages]] of the SpaceX reusable rocket launching system. Following the completion of the third [[SpaceX high-altitude controlled-descent tests|high-altitude controlled-descent test]], and the completion of the third low-altitude flight of the [[F9R Dev|second-generation prototype test vehicle]] (plus eight flights of the first-generation Grasshopper prototype flight test vehicle), SpaceX indicated that they are now able to consistently "reenter from space at hypersonic velocity, restart main engines twice, deploy landing legs and touch down at near zero velocity."<ref name=sn20140721/>
[[File:Falcon 9 1st stage re-entry with grid fins; DSCOVR mission (16849254595).png|thumb|Falcon 9 booster stage re-entry with grid fins, February 2015 following the launch of the [[DSCOVR]] mission]]
The technologies that were developed for this program, some of which are still being refined, include:
* [[Rocket engine restart|restartable]] [[ignition system]] for the first-stage booster.<ref name="musk20130428">{{cite tweet |user=elonmusk |number=328386732934430720 |title=First test of the Falcon 9-R (reusable) ignition system |date=April 28, 2013}}</ref><!-- the Falcon 9 second stage, Merlin 1C vacuum engine has had restartable ignition for some time. --> Restarts are required at both supersonic velocities in the upper atmosphere—in order to decelerate the high velocity away from the launch pad and put the booster on a descent trajectory back toward the launch pad—and at high [[transonic]] velocities in the lower atmosphere—in order to slow the terminal descent and to perform a soft landing.<ref name="pa20150110">{{cite video |people=Gwynne Shotwell |url=https://www.youtube.com/watch?v=XtNgWK4mm0M |title=Singapore Satellite Industry Forum 2013 - Opening Keynote |accessdate=April 9, 2016 |date=June 17, 2013 |time=16:15–17:05 |quote=The Dragon capsule has a shape that is stable on reentry from orbit, whereas rocket states traditionally are not stable on reentry, so there is a lot of software involved, a lot of guidance navigation and control involved, and a lot of thermal protection required; so we have to make advances in all those areas. We also have to restart the engines supersonically.}}</ref>
* new [[attitude control]] technology{{mdash}}for the booster stage and second stage{{mdash}}to bring the descending [[rocket body]] through the atmosphere in a manner conducive both to non-destructive return and [[Aerodynamic control surfaces|sufficient aerodynamic control]] such that the terminal phase of the [[VTVL|landing]] is possible.<ref name=pa20140114vid>
{{cite video |people=Gwynne Shotwell |url=https://www.youtube.com/watch?v=XtNgWK4mm0M |title=Singapore Satellite Industry Forum 2013 - Opening Keynote |accessdate=April 9, 2016 |date=June 17, 2013}}</ref> This includes sufficient roll [[Control system|control authority]] to keep the rocket from spinning excessively as occurred on the [[Falcon 9 Flight 6#Post-mission launch vehicle testing|first high-altitude flight test]] in September 2013, where the roll rate exceeded the capabilities of the booster [[attitude control system]] (ACS) and the fuel in the tanks "centrifuged" to the side of the tank shutting down the single engine involved in the low-altitude deceleration maneuver.<ref name="pa20130930" /><ref name=tss20140321b>{{cite AV media|people=Gwynne Shotwell |date=March 21, 2014 |title=Broadcast 2212: Special Edition, interview with Gwynne Shotwell |medium=audio file |url=http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 |accessdate=March 22, 2014 |archiveurl=https://web.archive.org/web/20140322013556/http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 |archivedate=March 22, 2014 |format=mp3 |time=51;50–52;55 |publisher=The Space Show |id=2212 |quote= |deadurl=yes |df= }}</ref> The technology needs to handle the transition from the vacuum of space at [[hypersonic]] conditions, decelerating to [[supersonic]] velocities and passing through [[transonic]] [[Buffet (turbulence)|buffet]], before relighting one of the main-stage engines at [[terminal velocity]].<ref name=pm20130930/>
* hypersonic [[grid fin]]s were added to the booster test vehicle design beginning on the [[Falcon 9 Flight 14|fifth ocean controlled-descent test flight]] in 2014 in order to enable precision landing. Arranged in an "X" configuration, the grid fins control the descending rocket's [[lift vector]] once the vehicle has returned to the atmosphere to enable a much more precise [[Landing ellipse|landing location]].<ref name=sx20141216>
{{cite web |title=X MARKS THE SPOT: FALCON 9 ATTEMPTS OCEAN PLATFORM LANDING |url=http://www.spacex.com/news/2014/12/16/x-marks-spot-falcon-9-attempts-ocean-platform-landing |publisher=SpaceX |accessdate=December 17, 2014 |date=December 16, 2014 |quote=A key upgrade to enable precision targeting of the Falcon 9 all the way to touchdown is the addition of four hypersonic grid fins placed in an X-wing configuration around the vehicle, stowed on ascent and deployed on reentry to control the stage’s lift vector. Each fin moves independently for roll, pitch and yaw, and combined with the engine gimbaling, will allow for precision landing – first on the autonomous spaceport drone ship, and eventually on land.}}<!-- quotation added as SpaceX often removes these sorts of news source pages after some months --></ref><ref name=blackmore2016/> Iteration on the design continued into 2017. Larger and more robust grid fins, made from forged [[titanium]] and left unpainted, were first tested in June 2017, and will be used on all reusable Block 5 Falcon 9 first stages starting in late 2017.<ref>[https://www.nasaspaceflight.com/2017/06/spacex-falcon-9-iridium-next-2-launch/ https://www.nasaspaceflight.com/2017/06/spacex-falcon-9-iridium-next-2-launch/]</ref>
[[File:Falcon 9 with CRS-3 Dragon in SLC-40 hangar (16855338881).jpg|thumb|left|Falcon 9 v1.1 with landing legs attached, in stowed position as the rocket is prepared for launch in its hangar]]
* [[Rocket engine throttling|throttleable rocket engine]] technology is required to reduce engine thrust because the full thrust of even a single [[Merlin 1D]] engine exceeds the weight of the nearly empty booster core.<ref name=fg20130321>{{cite news |last=Rosenberg |first=Zach |title=SpaceX Merlin 1D qualified for flight |url=http://www.flightglobal.com/news/articles/spacex-merlin-1d-qualified-for-flight-383738/ |accessdate=March 18, 2014 |newspaper=Flightglobal |date=March 21, 2013}}</ref><ref name=slr20140312>{{cite web |title=SpaceX Falcon 9 v1.1 Data Sheet |url=http://www.spacelaunchreport.com/falcon9v1-1.html |publisher=Space Launch Report |accessdate=March 18, 2014 |date=March 12, 2014}}</ref><ref name=blackmore2016/>
* [[attitude control|terminal guidance]] and landing capability,<ref name="nsj20130309">{{cite news |url=http://www.newspacejournal.com/2013/03/09/more-on-grasshoppers-johnny-cash-hover-slam-test/ |title=More on Grasshopper's "Johnny Cash hover slam" test |work=NewSpace Journal |last=Foust |first=Jeff |date=March 9, 2013 |accessdate=May 2, 2013}}</ref> including a [[Guidance, navigation and control|vehicle control system]] and a control system [[Real-time computing|software algorithm]] to be able to land a rocket with the thrust-to-weight ratio of the vehicle greater than one,<ref name="nbc20130309">{{cite news |url=http://cosmiclog.nbcnews.com/_news/2013/03/09/17251376-spacexs-elon-musk-shows-off-grasshopper-test-rockets-latest-hop?lite |title=SpaceX's Elon Musk shows off Grasshopper test rocket's latest hop |work=NBC News |last=Boyle |first=Alan |date=May 2, 2013 |accessdate=March 9, 2013}}</ref> with [[Closed-loop control|closed-loop]] [[thrust-vector|thrust vector]] and [[throttleable|throttle control]]<ref>{{cite news |url=http://www.dailykos.com/story/2013/03/09/1192883/-Woo-hoo-Awesome-SpaceX-Grasshopper-Hover-Slam-Launch-Doubles-Previous-Height-w-Video |title=Woo-hoo! Awesome SpaceX Grasshopper "Hover-Slam" Rocket Launch Doubles Previous Height |work=Daily Kos |date=March 9, 2013}}</ref><ref name=blackmore2016/>
* [[GN&C|navigation]] sensor suite for precision landing<ref name=pa20140114vid/><ref name="sx20130705">{{cite video |url=https://www.youtube.com/watch?v=eGimzB5QM1M |title=Grasshopper 325m Test {{!}} Single Camera (Hexacopter) |work=YouTube.com |publisher=SpaceX |date=June 14, 2013 |accessdate=July 6, 2013 }}</ref><ref name=blackmore2016/>
[[File:Autonomous Spaceport Drone Ship - Just Read the Instructions (16450469297).png|thumb|Autonomous Spaceport Drone Ship, in port in January 2015.]]
* a large [[floating landing platform]] in order to test pinpoint landings prior to receiving permission from the [[Federal government of the United States|US government]] to bring returning rocket stages into US [[airspace]] over land. In the event, SpaceX built the ''[[autonomous spaceport drone ship]]'' in 2014,<ref name=nsf20141124/> and conducted an initial flight test and landing attempt in January 2015.<ref name=nsf20141217>
{{cite news |last1=Bergin |first1=Chris |title=SpaceX confirms CRS-5 launch slip to January 6 |url=http://www.nasaspaceflight.com/2014/12/spacex-static-fire-falcon-9-crs-5/ |accessdate=December 24, 2014 |work=NASASpaceFlight.com |date=December 17, 2014}}</ref>
* large-surface-area [[thermal protection system]] to absorb the heat load of deceleration of the second stage from [[Orbital speed|orbital velocity]] to terminal velocity<ref name=pa20140114vid/><ref name=tsr20140324>{{cite journal |last=Foust |first=Jeff |title=Reusability and other issues facing the launch industry |journal=The Space Review |date=March 24, 2014 |url=http://www.thespacereview.com/article/2476/1 |accessdate=April 1, 2014}}</ref><ref name=blackmore2016/>
* lightweight, deployable [[Launch vehicle landing gear|landing gear]] for the booster stage.<ref name="satspot20110926" /><ref name=blackmore2016>
{{cite journal |title=Autonomous Precision Landing of Space Rockets |journal=The Bridge, National Academy of Engineering |date=Winter 2016 |last=Blackmore |first=Lars |volume=46 |issue=4 |pages=15–20 |issn=0737-6278 |url=http://web.mit.edu/larsb/www/nae_bridge_2016.pdf |accessdate=January 15, 2017}}</ref> In May 2013, the design was shown to be a nested, telescoping piston on an A-frame. The total span of the four [[carbon fiber]]/[[aluminum]] extensible landing legs<ref name="sxn20130729legs">{{cite web |url=http://www.spacex.com/news/2013/03/26/landing-leg |title=Landing Legs |work=SpaceX.com |date=July 29, 2013 |accessdate=December 4, 2013 |quote=The Falcon 9 first stage carries landing legs which will deploy after stage separation and allow for the rocket’s soft return to Earth. The four legs are made of state-of-the-art carbon fiber with aluminum honeycomb. Placed symmetrically around the base of the rocket, they stow along the side of the vehicle during liftoff and later extend outward and down for landing.}}</ref><ref name="sxn20130802fh_legs">{{cite web |url=http://www.spacex.com/news/2013/04/12/falcon-heavy-landing-legs |title=Falcon Heavy Landing Legs |work=SpaceX.com |date=April 12, 2013 |accessdate=December 4, 2013 |quote=The Falcon Heavy first stage center core and boosters each carry landing legs, which will land each core safely on Earth after takeoff. After the side boosters separate, the center engine in each will burn to control the booster’s trajectory safely away from the rocket. The legs will then deploy as the boosters turn back to Earth, landing each softly on the ground. The center core will continue to fire until stage separation, after which its legs will deploy and land it back on Earth as well. The landing legs are made of state-of-the-art carbon fiber with aluminum honeycomb. The four legs stow along the sides of each core during liftoff and later extend outward and down for landing.}}</ref> is approximately {{convert|60|ft|m|order=flip|sp=us}}, and weigh less than {{convert|2100|kg}}. Deployment system uses high-pressure [[Helium]] as the [[working fluid]].<ref name="musk20130502">{{cite news |url=http://www.newspacewatch.com/articles/spacex-shows-a-leg-for-the-quotf-ninerquot.html |title=SpaceX shows a leg for the "F-niner" |work=NewSpace Watch |last=Lindsey |first=Clark |date=May 2, 2013 |accessdate=May 2, 2013 <!-- REMOVED https://archive.is/ archive link, as a wikibot reports that is is on some sort of "local blacklist". See page history on 2016-04-05 for more info |archiveurl=https://archive.is/20130630001715/http://www.newspacewatch.com/articles/spacex-shows-a-leg-for-the-quotf-ninerquot.html |archivedate=June 30, 2013 --> |quote=F9R (pronounced F-niner) shows a little leg. Design is a nested, telescoping piston w A frame... High pressure helium. Needs to be ultra light. |subscription=yes}}</ref><ref name=nsf20140228>{{cite news |last=Bergin |first=Chris |title=SpaceX outlines CRS-3 landing legs plan toward first stage recovery ambitions |url=http://www.nasaspaceflight.com/2014/02/spacex-crs-3-landing-legs-plan-first-stage-recovery-ambitions/ |accessdate=May 10, 2014 |newspaper=NASAspaceflight.com |date=February 28, 2014}}</ref> With [[Falcon 9 first-stage landing tests#Flight 25|Flight 25]] it was announced that each landing leg contained a "crush core", to absorb the impact of landing for particularly hard landings.<ref name="space.com">{{cite news |last1=Wall |first1=Mike |title=SpaceX's Leaning Rocket Tower Comes Ashore (Photos) |url=http://www.space.com/33102-spacex-leaning-rocket-comes-ashore-photos.html |accessdate=June 7, 2016 |date=June 7, 2016}}</ref><ref>{{Cite web |url=https://twitter.com/elonmusk/status/736328917317910528?lang=en |title=Elon Musk on Twitter |website=Twitter |access-date=June 8, 2016 |quote=The crush core in the Falcon legs is reusable after soft landings, but needs to be replaced after hard.}}</ref>
== Economics of rocket reuse ==
In order to make the Falcon 9 reusable and return to the launch site, extra [[rocket propellant|propellant]] and [[landing gear]] must be carried on the first stage, requiring around a 30 percent reduction of the maximum payload to orbit in comparison with the expendable Falcon 9.<ref name="bbc20130930" /> [[Reusable launch system|Reflight]] of a previously used stage on a subsequent flight is dependent on the condition of the landed stage, and is a technique that has seen little use outside of the [[Space Shuttle]]'s reusable [[Space Shuttle Solid Rocket Booster|solid rocket boosters]]. In September 2013, SpaceX said that if all aspects of the test program were successful and if a customer is interested, the first reflight of a Falcon 9 booster stage could happen as early as late 2014.<ref name="bbc20130930" /><!-- should the historical statement re 2013 no longer belong in this section, it should probably move to the History subsection, and not just be deleted completely from this "good article." -->
In December 2015, following the recovery of the [[Falcon 9 Flight 20|first stage from December 22 launch]], SpaceX projected that the first reflight of a recovered booster would likely occur in 2016, but that their plan was to not refly December 22 recovered stage for that purpose.<ref name=bi20151225>
{{cite news |url=http://www.cbsnews.com/news/experts-applaud-spacex-landing-cautious-about-outlook/ |title=Elon Musk's SpaceX already knows what it's going to do with the history-making rocket — but it's not what you think |author=Jessica Orwig |work=Business Insider |date=December 25, 2015 |accessdate=December 25, 2015}}</ref>
Musk projects that the reflight step of the program will be "straightforward," because of the multiple full duration firings of the engines that have been done on the ground, and the multiple engine restarts that have already been demonstrated, with no significant degradation seen.<ref name=presserTranscript20151222>
{{cite web |title=Postlanding teleconference with Elon Musk |url=http://shitelonsays.com/transcript/postlanding-teleconference-with-elon-musk-2015-12-22# |date=December 22, 2015 |accessdate=December 25, 2015}}</ref>
Several industry analysts continue to see potential problems that could prevent economic reuse because costs to refurbish and relaunch the stage are not yet demonstrated. Moreover, the economic case for reuse will be highly dependent on launching frequently, and that is simply unknown as of 2015.<ref name=cbs20151222>
{{cite news |title=Experts applaud SpaceX rocket landing, potential savings |author=Bill Harwood |url=http://www.cbsnews.com/news/experts-applaud-spacex-landing-cautious-about-outlook/ |work=CBS News |date=December 22, 2015 |accessdate=December 25, 2015}}</ref>
If SpaceX is successful in developing the reusable technology, it is expected to significantly reduce the cost of access to space, and change the increasingly competitive market in space launch services.<ref name="bbc20130930">{{cite news |url=http://www.bbc.co.uk/news/science-environment-24331860 |title=Recycled rockets: SpaceX calls time on expendable launch vehicles |work=BBC News |last=Amos |first=Jonathan |date=September 30, 2013 |accessdate=October 2, 2013}}</ref><ref name=tsr20140310>{{cite journal |last=Boozer |first=R.D. |title=Rocket reusability: a driver of economic growth |journal=The Space Review |date=March 10, 2014 |url=http://www.thespacereview.com/article/2466/1 |accessdate=March 25, 2014}}</ref> Michael Belfiore wrote in ''[[Foreign Policy (magazine)|Foreign Policy]]'' in 2013 that, at a published cost of {{USD|56.5 million}} per launch to [[low Earth orbit]], "Falcon 9 rockets are already the cheapest in the industry. Reusable Falcon 9s could drop the price by an [[order of magnitude]], sparking more space-based enterprise, which in turn would drop the cost of access to space still further through economies of scale."<ref name=fp20131209>{{cite news |url=https://foreignpolicy.com/articles/2013/12/02/the_rocketeer_elon_musk |title=The Rocketeer |work=[[Foreign Policy (magazine)|Foreign Policy]] |last=Belfiore |first=Michael |date=December 9, 2013 |accessdate=December 11, 2013}}</ref> Even for military launches, which have a number of contractual requirements for additional launch services to be provided, SpaceX's price is under {{USD|100 million}}.<ref name=mit20140422>
{{cite news |last=Belfiore |first=Michael |title=SpaceX Brings a Booster Safely Back to Earth |url=http://www.technologyreview.com/news/526806/spacex-brings-a-booster-safely-back-to-earth/ |accessdate=April 25, 2014 |newspaper=MIT Technology Review |date=April 22, 2014}}</ref><ref name=bi20141125>
{{cite news |last1=Orwig |first1=Jessica |title=Elon Musk Just Unveiled A Game-Changing Ocean Landing Pad For His Reusable Rockets |url=http://www.businessinsider.com/elon-musk-rockets-that-land-at-sea-2014-11 |accessdate=December 11, 2014 |work=Business Insider |date=November 25, 2014 |quote=''The first successful "soft landing" of a Falcon 9 rocket happened in April of this year''}}</ref>
[[File:Falcon 9 First Stage Reusability Graphic.jpg|thumb|upright=2|Depiction of Falcon 9 landing trajectory for some of the floating-platform recovery tests]]<!-- not all of the controlled-descent tests had three post-separation burns; e.g., some of the early ones only had two burns, and skipped the boostback burn. -->
Space industry analyst Ajay Kothari has noted that SpaceX reusable technology could do for [[space transport]] "what jet engines did for air transportation sixty years ago when people never imagined that more than 500 million passengers would travel by airplanes every year and that the cost could be reduced to the level it is—all because of passenger volume and reliable reusability."<ref name=tsr20140414>
{{cite news |last=Kothari |first=Ajay P. |title=Robust and reusable? |url=http://www.thespacereview.com/article/2490/1 |accessdate=April 14, 2014 |newspaper=The Space Review |date=April 14, 2014}}</ref>
SpaceX said in January 2014 that if they are successful in developing the reusable technology, launch prices of around {{USD|5 to 7 million}} for a reusable Falcon 9 were possible,<ref name=ps20140114>{{cite news |last=Messier |first=Doug |title=Shotwell: Reusable Falcon 9 Would Cost $5 to $7 Million Per Launch |url=http://www.parabolicarc.com/2014/01/14/shotwell/ |accessdate=January 15, 2014 |newspaper=Parabolic Arc |date=January 14, 2014}}</ref>
and following the successful first stage recovery in December 2015, Musk said that "the potential cost reduction over the long term is probably in excess of a factor of 100."<ref name=cbs20151222/>
{{asof|2014|03}} launch service providers who [[Market competition|compete]] with SpaceX were not planning to develop similar technology or offer competing reusable launcher options. Neither [[International Launch Services|ILS]], which markets launches of the Russian [[Proton rocket]]; [[Arianespace]]; nor [[SeaLaunch]] were planning on developing and marketing reusable launch vehicle services. SpaceX was the only competitor that projected a sufficiently [[Price elasticity of demand|elastic]] market on the demand side to justify the costly development of reusable rocket technology and the expenditure of [[Capital (economics)|private capital]] to develop options for that theoretical market opportunity.<ref name=tsr20140324/>
{{As of|2014}}, the Falcon 9 v1.1 rocket was designed with about 30 percent more capacity than its official payload specifications; the additional performance was reserved for SpaceX to perform [[Falcon 9 first-stage landing tests|first-stage re-entry and landing tests]] towards reusability while still achieving the specified orbital payload delivery for customers.<ref name=tss20140321a>{{cite AV media|people=Gwynne Shotwell |date=March 21, 2014 |title=Broadcast 2212: Special Edition, interview with Gwynne Shotwell |medium=audio file |url=http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 |accessdate=March 22, 2014 |archiveurl=https://web.archive.org/web/20140322013556/http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 |archivedate=March 22, 2014 |format=mp3 |time=08:15–11:20 |publisher=The Space Show |id=2212 |quote=[Falcon 9 v1.1] vehicle has thirty percent more performance than what we put on the web and that extra performance is reserved for us to do our reusability and recoverability [tests] ... current vehicle is sized for reuse. |deadurl=yes |df= }}</ref>
In order to achieve the full economic benefit of the reusable technology, it is necessary that the reuse be both rapid and complete—without the long and costly refurbishment period or partially reusable design that plagued earlier attempts at reusable launch vehicles. SpaceX has been explicit that the "huge potential to open up space flight"<ref name=nsf20140422>{{cite news |last=Bergin |first=Chris |title=Rockets that return home – SpaceX pushing the boundaries |url=http://www.nasaspaceflight.com/2014/04/rockets-return-home-spacex-pushing-boundaries/ |accessdate=April 23, 2014 |newspaper=NASAspaceflight.com |date=April 22, 2014}}</ref> is dependent on achieving both complete and rapid reusability.<ref name=aw20140428a/><ref name=mit20140422/>
CEO Musk stated in 2014 that success with the technology development effort could reduce "the cost of spaceflight by a factor of 100"<ref name=sdc20140907>
{{cite news |last1=Wall |first1=Mike |title=Dazzling SpaceX Nighttime Launch Sends AsiaSat 6 Satellite Into Orbit |url=http://www.space.com/27052-spacex-launches-asiasat6-satellite.html |accessdate=September 7, 2014 |publisher=SPACE.com |date=September 7, 2014 |quote=''SpaceX's work with the F9R is part of an effort to develop fully and rapidly reusable launch systems, a key priority for the company. Such technology could slash the cost of spaceflight by a factor of 100.''}}</ref> because the cost of the propellant/oxidizer on the Falcon 9 is only 0.3 percent of the total cost of the vehicle.<ref>{{cite web |url=http://www.space.com/21386-spacex-reusable-rockets-cost.html |title=SpaceX Chief Says Reusable First Stage Will Slash Launch Costs |author=Peter B. de Selding, Space News |work=Space.com}}</ref>
Separate from the [[Space launch market competition|market competition]] brought about by SpaceX lower launch prices and the potential future of even more radically lower launch prices if the technology can be completed successfully, ''[[Aviation Week]]'' said in 2014 that "SpaceX reusable launch work is an [[Research and development|R&D]] model"—"The audacity of the concept and speed of the program’s progress make it an exemplar. ... [the] breakneck pace of development has been almost [[Apollo program|Apollo]]-like in its execution... [even while] success is far from guaranteed."<ref name=aw20140428b>{{cite news |title=SpaceX’s Plan Shows Aggressive Investment In R&D |url=http://m.aviationweek.com/space/editorial-spacex-s-plan-shows-aggressive-investment-rd |accessdate=May 17, 2014 |newspaper=Aviation Week |date=April 28, 2014}}</ref>
On March 9, 2016, SpaceX President Gwynne Shotwell gave a more realistic appraisal of the potential savings of a reused launch now that attempts to reuse the second stage had been abandoned due to cost and weight issues. She said at {{USD|1 million}} cost of refueling and {{USD|3 million}} cost of refurbishing a used first stage could potentially allow a launch to be priced as low as {{USD|40 million}}, a 30% saving. SpaceX biggest customer SES said it wants to be the first to ride a reused vehicle, however it wants a launch price of {{USD|30 million}} or a 50% saving to offset the risk of pioneering the process.<ref>{{cite web |url=http://spacenews.com/spacex-says-reusable-stage-could-cut-prices-by-30-plans-first-falcon-heavy-in-november/ |title=SpaceX says reusable stage could cut prices 30 percent, plans November Falcon Heavy debut |work=SpaceNews.com |date=2016-03-10 |accessdate=2017-05-27 }}</ref>
According to Elon Musk, almost every piece of the Falcon should be reused over 100 times. Heat shields and a few other items should be reused over 10 times before replacement.<ref>https://twitter.com/elonmusk/status/726216836069515264</ref> In March 2017, SpaceX announced progress in their experiments to recover, and eventually reuse, the 6-million dollar [[payload fairing]]. On the [[SES-10]] mission, one of the fairing halves performed a controlled atmospheric reentry and [[splashdown]] using thrusters and a steerable parachute; fairings are eventually slated to land on a floating "bouncy castle" structure.<ref name=floridatoday_26216836069515264>{{cite news|url= http://www.floridatoday.com/story/tech/science/space/2017/03/31/things-we-learned-spacex-elon-musk-falcon9-reusability-kennedy-space-center-florida-ses10/99869966/ |title= Things we learned after SpaceX's historic Falcon 9 relaunch and landing |website= [[Florida Today]] |first= Emre |last= Kelly |date= 2017-03-31 |accessdate= 2017-04-01}}</ref>
SpaceX began re-flight of previously-launched booster stages in 2017. The first re-flight was accomplished in March 2017, nearly a year after the booster's [[maiden flight]]; the second was in June 2017, only five months after its maiden flight. Both were successful, and both [[insurer]]s and launch service customers are readily supporting the newly emerging market in launch services provided by multiple-use boosters.<ref name=sir-20170626>{{cite web |url=https://www.spaceintelreport.com/spacex-cuts-flight-refurbish-reflight-time-falcon-9-first-stage/ |title=SpaceX cuts flight-to-reflight time for Falcon 9 first stage |work=Space Intel Report |first=Peter B. |last=de Selding |date=June 26, 2017 |access-date=June 27, 2017}}</ref>
== Technical feasibility ==
Prior to the reusability program's success in December 2015, the [[Return To Launch Site|return]] of an orbital launch system booster rocket had never been accomplished, and many questioned both technical and economic feasibility. And even after this success, the ''rapid'' reuse of a rocket has not been attempted. Developing a reusable rocket is extremely challenging due to the small percentage of a rocket's mass that can make it to orbit.<ref name="sdc20110930"/><ref name=am201404>
{{cite news |last1=Clash |first1=Jim |title=Elon Musk Interview |url=http://www.askmen.com/entertainment/right-stuff/elon-musk-interview-2.html |accessdate=September 27, 2014 |work=AskMen |date=April 2014 |quote=''Expendable rockets, which many smart people have worked on in the past, get maybe 2% of liftoff mass to orbit -- really not a lot. Then, when they’ve tried reusability, it’s resulted in negative payload, a 0 to 2% minus payload [laughs]. The trick is to figure out how to create a rocket that, if it were expendable, is so efficient in all of its systems that it would put 3% to 4% of its mass into orbit. On the other side, you have to be equally clever with the reusability elements such that the reusability penalty is no more than 2%, which would leave you with a net ideally of still 2% of usable load to orbit in a reusable scenario, if that makes sense. You have to pry those two things apart: Push up payload to orbit, push down the mass penalty for reusability -- and have enough left over to still do useful work.''}}</ref> Typically, a rocket's payload is only about 3% of the mass of the rocket which is also roughly the amount of mass in fuel that is required for the vehicle's re-entry.<ref name="youtube20110929">{{cite web |url=https://www.youtube.com/watch?v=xrVD3tcVWTY |title=National Press Club: The Future of Human Spaceflight |date=September 29, 2011}}</ref>
Elon Musk said at the beginning of the program that he believed the return, vertical landing and recovery was possible because the SpaceX manufacturing methodologies result in a rocket efficiency exceeding the typical 3% margin. A SpaceX rocket operating in the reusable configuration has approximately 30% less payload lift capacity than the same rocket in an [[expendable rocket|expendable]] configuration.<ref name=pm20130930/>
Although the [[reusable launch system]] technology was developed and initially used for the first stages of the Falcon family of rockets<ref name=sn20141024/> it is particularly well suited to the Falcon Heavy where the two [[Modular rocket|outer cores]] [[separation event|separate]] from the rocket earlier in the flight, and are therefore moving more slowly at stage separation. For example, on [[Falcon 9 Flight 20|Falcon 9 flight 20]], the speed at separation was close to 6000 km/h<ref>{{cite video |url=https://www.youtube.com/watch?v=3G8GJQumBFs |title=ORBCOMM-2 Full Launch Webcast |time=25:25 |publisher=SpaceX |accessdate=April 9, 2016 |date=December 21, 2015}}</ref> and this allowed a return to near the launch site. On [[Falcon 9 Flight 22|flight 22]], going to a more-energetic [[Geostationary transfer orbit|GTO]] orbit, the higher velocity at separation was between 8000 and 9000 km/h. At these faster speeds it is not possible to return the booster to near the launch site for a landing; if a landing is attempted it needs to be hundreds of kilometers downrange on an [[Autonomous spaceport drone ship|autonomous droneship]].
== Test program ==
In 2013 SpaceX was testing reusable technologies both for its [[Booster (rocketry)|first-stage booster]] launch vehicle designs (with three test vehicles : [[Grasshopper (rocket)|Grasshopper]], [[F9R Dev1]], and [[F9R Dev2]]) — and for its new reusable [[Dragon V2]] [[space capsule]] (with a low-altitude test vehicle called [[DragonFly (rocket)|DragonFly]]).
SpaceX has publicly disclosed a multi-element, incremental test program for booster stages that includes four aspects:
* low-altitude (less than {{convert|760|m|ft|-2|disp=x|/|abbr=on}}<ref name="faa20110922" /><ref name=wt20130508>{{cite news |last=Abbott |first=Joseph |title=SpaceX's Grasshopper leaping to NM spaceport |url=http://www.wacotrib.com/news/business/spacex-s-grasshopper-leaping-to-nm-spaceport/article_de2126cd-d6ec-563b-b84b-532641e709e3.html |accessdate=October 25, 2013 |newspaper=Waco Tribune |date=May 8, 2013}}</ref>), low-velocity testing of its single-engine [[Grasshopper (rocket)|Grasshopper]] technology-demonstrator at its Texas test site
* low-altitude (less than {{convert|3000|m|ft|-2|disp=x|/|abbr=on}}), low-velocity testing of a much larger, second-generation, three-engine test vehicle called [[F9R Dev1]]. The second generation vehicle includes extensible landing legs and will be tested at the Texas test site<ref name=tsr20140505>{{cite news |last=Foust |first=Jeff |title=Following up: reusability, B612, satellite servicing |url=http://www.thespacereview.com/article/2505/1 |accessdate=May 6, 2014 |newspaper=The Space Review |date=May 5, 2014}}</ref>
* high-altitude, mid-velocity testing was planned but cancelled in favor of [[Falcon 9 first-stage landing tests|post-mission re-entry tests of first-stage boosters]]. It would have used F9R Dev2 at a SpaceX leased facility at [[Spaceport America]] in [[New Mexico]].
* high-altitude ({{convert|91|km|ft|-5|disp=x|/|abbr=on}}<ref name="nbf20130323">{{cite news |url=http://nextbigfuture.com/2013/03/spacex-may-try-to-land-recover-first.html |title={{Sic |hide=y|Spacex}} May try to "land / recover" the first stage of it next Falcon 9 v1.1 launch this summer |work=Next Big Future |first=Brian |last=Wang |date=March 23, 2013 |accessdate=April 6, 2013}}</ref>), very-high-velocity (approximately {{nowrap|2.0 km/s}}; {{nowrap|6,500 km/h; 4,100 mph; Mach 6}}<ref name="pm20120207" />) [[ballistic reentry]], [[SpaceX high-altitude controlled-descent tests|controlled-deceleration and controlled-descent tests]] of post-mission (spent) Falcon 9 booster stages following a subset of Falcon 9 launches that began in 2013.
Eight low-altitude booster flight tests were made by Grasshopper in 2012 and 2013.
The first [[booster rocket|booster return]] controlled-descent test from high-altitude was made in September 2013, with a second test in April,<ref name="bbc20130930" /><ref name="ut20140419" /><ref name=dn20140224/>
a [[Falcon 9 Flight 10|third test flight]] in July<ref name=nsf20140728>
{{cite news |last1=Bergin |first1=Chris |title=SpaceX Roadmap building on its rocket business revolution |url=http://www.nasaspaceflight.com/2014/07/spacex-roadmap-rocket-business-revolution/ |accessdate=July 28, 2014 |publisher=NASAspaceflight |date=July 28, 2014 |quote=''At this point, we are highly confident of being able to land successfully on a floating launch pad or back at the launch site and refly the rocket with no required refurbishment''}}</ref>
and a [[Falcon 9 Flight 13|fourth test]] in September 2014. All four test flights to date were intended to be over-water, simulated landings.<ref name=sn20140721/>
Five low-altitude booster flight tests of F9R Dev1 were flown during April–August 2014, before the vehicle self-destructed for safety reasons on the fifth flight.<ref name=wt20140417>
{{cite news |last=Abbott |first=Joseph |title=Grasshopper's successor flies at SpaceX's McGregor site |url=http://www.wacotrib.com/blogs/joe_science/grasshopper-s-successor-flies-at-spacex-s-mcgregor-site/article_66310240-c67f-11e3-bf29-001a4bcf887a.html |accessdate=April 18, 2014 |newspaper=Waco Tribune |date=April 17, 2014}}</ref><ref name=nsj20140823>
{{cite news |last1=Foust |first1=Jeff |title=Falcon 9 test vehicle destroyed in accident |url=http://www.newspacejournal.com/2014/08/23/falcon-9-test-vehicle-destroyed-in-accident/ |accessdate=August 23, 2014 |publisher=NewSpace Journal |date=August 23, 2014}}</ref>
=== Flight test vehicles ===
[[File:SpaceX Grasshopper rocket midflight.png|thumb|Grasshopper rocket performing a 325 meter flight followed by a soft propulsive landing in an attempt to develop technologies for a reusable launch vehicle.]]
SpaceX used a set of experimental technology-demonstrator, [[suborbital]] [[Reusable launch system|reusable launch vehicles]] (RLV) to begin [[flight testing]] their reusable rocket technologies in 2012. Two versions of the prototype reusable test rockets were built—the 106-foot tall ''Grasshopper'' (formerly designated as ''Grasshopper v1.0'') and the 160-foot tall ''Falcon 9 Reusable Development Vehicle'', or ''F9R Dev1''—formerly known as ''Grasshopper v1.1''<ref name=nsf20140422/>—as well as a [[space capsule|capsule prototype]] for testing propulsive landings of the [[Dragon 2|Dragon]] crew and cargo capsule for the Falcon 9—''DragonFly''.<ref name=nsf20140422/>
Grasshopper was built in 2011–2012 for low-altitude, low-velocity hover testing that began in September 2012 and concluded in October 2013 after eight test flights.<ref name="faa20110922" /><ref name="satspot20110926" /><ref name=nsf20140422/>
The second prototype vehicle design, F9R Dev1, was built on the much larger [[Falcon 9 v1.1]] booster stage was used to further extend the low-altitude flight testing [[flight envelope|envelope]] on a vehicle that better matched the actual flight hardware, and made five test flights in 2014.<ref name=nsf20140422/><ref name="msnbc20110927">{{cite news |url=http://www.nbcnews.com/id/44692930/ |title=A rocket that lifts off—and lands—on launch pad |work=NBC News |last=Klotz |first=Irene |date=September 27, 2011 |accessdate=November 23, 2011}}</ref><ref name="nsw20121002" />
The low-altitude, low-speed flights of the test vehicle rockets and capsule were conducted at the [[SpaceX Rocket Development and Test Facility|SpaceX Rocket Test Facility]] in [[McGregor, Texas]]<ref name="faa20110922" /><ref name="satspot20110926" /><ref name=nsf20140422/>
==== Grasshopper ====
{{main|Grasshopper (rocket)}}
Grasshopper, the company's first [[VTVL]] test vehicle, consisted of a [[Falcon 9 v1.0]] first-stage tank, a single [[Merlin 1D|Merlin-1D]] engine, and four permanently attached steel landing legs. It stood {{convert|106|ft}} tall.<ref name="satspot20110926">{{cite news |url=http://satellite.tmcnet.com/topics/satellite/articles/222324-spacex-plans-test-reusable-suborbital-vtvl-rocket-texas.htm |title=SpaceX Plans to Test Reusable Suborbital VTVL Rocket in Texas |newspaper=Satellite Spotlight |last=Mohney |first=Doug |date=September 26, 2011 |accessdate=November 21, 2013}}</ref> SpaceX built a {{Convert|0.5|acre|ha|adj=on}} concrete launch facility at its Rocket Development and Test Facility in [[McGregor, Texas]] to support the Grasshopper flight test program.<ref name="sfn20120709">{{cite news |url=http://www.spaceflightnow.com/news/n1207/10grasshopper/ |title=Reusable rocket prototype almost ready for first liftoff |newspaper=Spaceflight Now |first=Stephen |last=Clark |date=July 9, 2012 |accessdate=July 13, 2012 |quote=SpaceX has constructed a half-acre concrete launch facility in McGregor, and the Grasshopper rocket is already standing on the pad, outfitted with four insect-like silver landing legs.}}</ref>
Grasshopper was also known as Grasshopper version 1.0, or Grasshopper v1.0, prior to 2014 during the time the followon Grasshopper-class test vehicles were being built.
In addition to three test flights in 2012, five additional tests were successfully flown by the end of October 2013{{mdash}}including the fourth test overall in March 2013{{mdash}}in which Grasshopper doubled its highest leap to rise to {{convert|80.1|m|sp=us}} with a 34-second flight.<ref name="faa20130310">{{cite news |url=http://www.spacex.com/news/2013/03/23/grasshopper-completes-highest-leap-date |title=Grasshopper Completes Highest Leap to Date |work=SpaceX.com |date=March 10, 2013 |accessdate=April 21, 2013}}</ref> In the seventh test, in August 2013, the vehicle flew to {{convert|250|m|ft|sp=us}} during a 60-second flight and executed a {{convert|100|m|ft|sp=us|adj=on}} lateral maneuver before returning to the pad.<ref name="nbc20130814">{{cite news |url=http://www.nbcnews.com/science/spacexs-grasshopper-test-rocket-flies-sideways-successfully-6C10923106 |title=SpaceX's Grasshopper test rocket flies sideways successfully |work=NBC News |last=Boyle |first=Alan |date=August 14, 2013 |accessdate=August 15, 2013}}</ref> Grasshopper made its eighth and final test flight on October 7, 2013, flying to {{convert|744|m|sp=us}} (0.46 miles) before making its eighth successful landing.<ref name="sx20131012fb">{{cite video |url=https://www.youtube.com/watch?v=9ZDkItO-0a4 |title=Grasshopper flies to its highest height to date |publisher=SpaceX |date=October 12, 2013 |accessdate=April 9, 2016}}</ref> The Grasshopper test vehicle is now retired.<ref name="sn20131017">{{cite news |url=http://www.spacenews.com/article/launch-report/37740spacex-retires-grasshopper-new-test-rig-to-fly-in-december |title=SpaceX Retires Grasshopper, New Test Rig To Fly in December |work=Space News |last=Klotz |first=Irene |date=October 17, 2013 |accessdate=October 21, 2013}}</ref>
==== Falcon 9 Reusable Development Vehicle ====
As early as October 2012, SpaceX discussed development of a second-generation Grasshopper test vehicle, which was to have lighter landing legs that fold up on the side of the rocket, a different engine bay, and would be nearly 50% longer than the first Grasshopper vehicle.<ref name="nsw20121002">{{cite news |url=http://www.newspacewatch.com/articles/a-2nd-gen-grasshopper-a-new-video-of-first-hop.html |title=A 2nd-gen Grasshopper + A new video of first hop |work=NewSpace Watch |last=Lindsey |first=Clark |date=October 2, 2012 |accessdate=November 4, 2012 <!-- REMOVED https://archive.is/ archive link, as a wikibot reports that is is on some sort of "local blacklist". See page history on 2016-04-05 for more info |archiveurl=https://archive.is/20130104030313/http://www.newspacewatch.com/articles/a-2nd-gen-grasshopper-a-new-video-of-first-hop.html |archivedate=January 4, 2013 --> |subscription=yes}}</ref> In March 2013, SpaceX announced that the larger Grasshopper-class<!-- then referred to as ''Grasshopper v1.1'' --> suborbital flight vehicle would be constructed out of the {{nowrap|[[Falcon 9 v1.1]]}} first-stage tank that was used for qualification testing at the SpaceX Rocket Development and Test Facility in early 2013. It was rebuilt as the {{nowrap|F9R Dev1}} with extensible landing legs.
The second VTVL flight test vehicle—F9R Dev1, built on the much longer [[Falcon 9 v1.1]] first-stage tank, with retractable landing legs—made its first test flight on April 17, 2014.<ref name=nsf20140422/><ref name=wt20140417/> F9R Dev1 was used for low-altitude test flights in the McGregor, Texas area—projected maximum altitude below {{convert|10000|ft|order=flip|sp=us}}<ref name=nsf20140422/>—with a total of five test flights, all made during 2014.
This vehicle self-destructed as a safety measure during its fifth test flight on August 22, 2014.<ref>{{cite tweet |user=elonmusk |number=502974683864518657 |title=Three engine F9R Dev1 vehicle auto-terminated during test flight. No injuries or near injuries. Rockets are tricky … |date=August 22, 2014 |accessdate=April 9, 2016}}</ref>
By April 2014, a third flight test vehicle—F9R Dev2—was being built and was planned to be flown at the high-altitude test range available at [[Spaceport America]] in [[New Mexico]] where it was expected to be flown at altitudes up to {{convert|300000|ft|order=flip|sp=us}}-plus.<ref name=nsf20140422/> It was never flown as SpaceX moved the high-altitude testing program to its [[SpaceX Falcon 9 booster post-mission, controlled-descent, test program|controlled-descent testing of used boosters]] following their use on a paid orbital launch and ascent.
==== DragonFly ====
{{main|DragonFly (rocket)}}
[[DragonFly (rocket)|DragonFly]] is a prototype test article for a propulsively landed version of the [[SpaceX Dragon]] [[space capsule|capsule]], a [[suborbital spaceflight|suborbital]] [[reusable launch vehicle]] (RLV), intended for low-altitude [[flight test]]ing. It will undergo a test program in Texas at the McGregor Rocket Test Facility, in 2014–2015.<ref name=nbc20140521/><ref name=faa201311>{{cite web |last1=James |first1=Michael |last2=Salton |first2=Alexandria |last3=Downing |first3=Micah |title=Draft Environmental Assessment for Issuing an Experimental Permit to SpaceX for Operation of the Dragon Fly Vehicle at the McGregor Test Site, Texas, May 2014 – Appendices |publisher=Blue Ridge Research and Consulting, LCC |pages=12 |date=November 12, 2013 |url=http://www.faa.gov/about/office_org/headquarters_offices/ast/media/20140513_DragonFly_DraftEA_Appendices%28reduced%29.pdf}}</ref>
The DragonFly test vehicle is powered by eight [[SuperDraco]] engines, arranged in a redundant pattern to support [[fault-tolerance]] in the propulsion system design.<ref name=wt20140522/> SuperDracos utilize a [[storable propellant]] mixture of [[monomethyl hydrazine]] (MMH) [[fuel]] and [[nitrogen tetroxide]] [[oxidizer]] (NTO), the same propellants used in the much smaller [[Draco (rocket engine family)|Draco]] thrusters used for [[attitude control]] and [[Reaction control system|maneuvering]] on the first-generation [[Dragon spacecraft]].<ref name=faa201311/>
While SuperDraco engines are capable of {{convert|16400|lbf|N|order=flip}} of thrust, during use on DragonFly flight test vehicle each will be [[Rocket engine throttling|throttled]] to less than {{convert|15325|lbf|N|order=flip}} to maintain vehicle stability.<ref name=faa201311/>
A test flight program of thirty flights has been proposed, including two ''propulsive assist'' (parachutes plus thrusters) and two ''propulsive landing'' (no parachutes) on flights dropped from a helicopter at an altitude of approximately {{convert|10000|ft|m|sp=us|order=flip}}. The other 26 test flights are projected to take off from a [[launch pad|pad]]: eight to be ''propulsive assist hops'' (landing with parachutes plus thrusters) and 18 to be ''full propulsive hops'', similar to the [[Grasshopper (rocket)|Grasshopper]] and [[F9R Dev]] booster stage test flights.<ref name=faa201311/><ref name=wt20140522>
{{cite news |last=Abbott |first=Joseph |title=Grasshopper to DragonFly: SpaceX seeks approval for new McGregor testing |url=http://www.wacotrib.com/blogs/joe_science/grasshopper-to-dragonfly-spacex-seeks-approval-for-new-mcgregor-testing/article_11d0c40a-e1f6-11e3-a868-001a4bcf887a.html |accessdate=May 23, 2014 |newspaper=Waco Tribune |date=May 22, 2014}}</ref>
The DragonFly test program is not expected to start until after the completion of the [[F9R Dev1]] booster testing at the McGregor facility.<ref name=wt20140522/>
=== Falcon 9 booster post-mission flight tests ===
[[File:CRS-6 first stage booster landing attempt.jpg|thumb|upright=0.6|CRS-6 booster landing attempt]]
{{Main|Falcon 9 first-stage landing tests}}
In an arrangement unusual for launch vehicles, some first stages of the SpaceX Falcon 9 v1.1 rockets are being used for propulsive-return controlled-descent flight tests after they complete the boost phase of an orbital flight. These boosters would ordinarily just be discarded in the ocean after setting their payloads on their way. The over-water tests take place in the Pacific and Atlantic oceans south of [[Vandenberg Air Force Base]] and east of [[Cape Canaveral Air Force Station]]. The first flight test occurred on September 29, 2013, after the second stage with the [[CASSIOPE]] and [[nanosat]] payloads separated from the booster. These descent and simulated landing tests continued over the next two years, with the second flight test taking place on April 18, 2014,<ref name="bbc20130930" /><ref name="ut20140419" /><ref name=dn20140224/> and four subsequent tests conducted in 2015.<ref name=nsf20151231>
{{cite news |last1=Gebhardt |first1=Chris |title=Year In Review, Part 4: SpaceX and Orbital ATK recover and succeed in 2015 |url=http://www.nasaspaceflight.com/2015/12/yir4-spacex-orbital-atk-recover-succeed-2015/ |accessdate=January 1, 2016 |work=NASASpaceFlight.com |date=December 31, 2015}}</ref>
==== Re-entry and controlled descent development ====
Following analysis of the flight test data from the first booster-controlled descent in September 2013, SpaceX announced it had successfully tested a large amount of new technology on the flight, and that coupled with the technology advancements made on the Grasshopper low-altitude landing demonstrator, they were ready to test a full recovery of the booster stage. The first flight test was successful; SpaceX said it was "able to successfully transition from vacuum through [[hypersonic]], through [[supersonic]], through [[transonic]], and light the engines all the way and control the stage all the way through [the atmosphere]".<ref name=pm20130930>{{cite news |url=http://www.popularmechanics.com/science/space/rockets/musk-spacex-now-has-all-the-pieces-for-reusable-rockets-15985616 |title=Musk: SpaceX Now Has "All the Pieces" For Truly Reusable Rockets |work=Popular Mechanics |last=Belfiore |first=Michael |date=September 30, 2013 |accessdate=October 17, 2013}}</ref> Musk said, "the next attempt to recovery [sic] the Falcon 9 first stage will be on the fourth flight of the upgraded rocket. This would be [the] third commercial Dragon cargo flight to ISS."<ref name="pa20130930">{{cite news |url=http://www.parabolicarc.com/2013/09/29/falcon-9-launch-payloads-orbit-vandenberg/ |title=Falcon 9 Launches Payloads into Orbit From Vandenberg |work=Parabolic Arc |last=Messier |first=Doug |date=September 29, 2013 |accessdate=September 30, 2013}}</ref>
This second flight test took place during the April 2014 Dragon flight to the ISS. SpaceX attached [[Launch vehicle landing gear|landing legs]] to the first stage, decelerated it over the ocean and attempted a simulated landing over the water, following the ignition of the second stage on the [[SpaceX CRS-3|third cargo resupply mission]] contracted to NASA. The first stage was successfully slowed down enough for a soft landing over the Atlantic Ocean.<ref name="ut20140419" /> SpaceX announced in February 2014 the intent to continue the tests to land the first-stage booster in the ocean until precision control from hypersonic all the way through subsonic regimes has been proven.<ref name=dn20140224>{{cite news |last=Klotz |first=Irene |title=SpaceX Falcon Rocket to Test Landing Legs |url=http://news.discovery.com/space/private-spaceflight/spacex-falcon-rocket-to-test-precision-landing-legs-140224.htm |accessdate=February 25, 2014 |newspaper=Discovery News |date=February 24, 2014}}</ref>
Five additional controlled-descent tests were conducted in the remainder of 2014 through April 2015, including two attempts to land on a [[floating landing platform]]—a SpaceX-built [[Autonomous Spaceport Drone Ship]]—on the [[Atlantic Ocean]] east of the launch site, both of which brought the vehicle to the landing platform, but neither of which resulted in a successful landing.
==== First landing on ground pad ====
[[File:ORBCOMM-2_First-Stage_Landing_(23271687254).jpg|thumb|Falcon 9 Flight 20's first stage landing viewed from a helicopter, December 22, 2015.]]
During the [[SpaceX CRS-7|2015 launch hiatus]], SpaceX requested regulatory approval from the [[FAA]] to attempt returning their [[Falcon 9 Flight 20|next flight]] to [[CCAFS|Cape Canaveral]] instead of targeting a floating platform in the ocean. The goal was to [[VTVL|land the booster vertically]] at the leased ''[[Landing Zone 1]]'' facility—the former [[Launch Complex 13]] where SpaceX had recently built a large rocket landing pad.<ref name=ft201511201>
{{cite news |last1=Dean |first1=James |title=SpacexSpaceX wants to land next booster at Cape Canaveral |url=http://www.floridatoday.com/story/tech/science/space/spacex/2015/12/01/spacex-wants-land-next-booster-cape-canaveral/76576142/ |accessdate=December 2, 2015 |work=Florida Today |date=December 1, 2015}}</ref>
The FAA approved the safety plan for the ground landing on December 18, 2015.<ref name=os20151220>{{cite news |title=SpaceX aims for Sunday launch and ground landing |url=http://www.orlandosentinel.com/news/space/go-for-launch/os-spacex-engine-testing-sunday-launch-20151218-post.html |work=Orlando Sentinel |date=December 20, 2015 |accessdate=December 20, 2015}}</ref> The first stage landed successfully on target at 20:38 local time on December 21 (01:38 UTC on December 22).<ref>{{cite news |url=https://www.theverge.com/2015/12/21/10640306/spacex-elon-musk-rocket-landing-success |title=SpaceX successfully landed its Falcon 9 rocket after launching it to space |work=[[The Verge]] |first=Loren |last=Grush |date=December 21, 2015 |accessdate=April 9, 2016}}</ref><ref name=nsf20151231/>
SpaceX does not plan to fly the ''[[Falcon 9 Flight 20]]'' first stage again.<ref>{{cite news |url=https://www.theverge.com/2015/12/21/10642028/spacex-falcon-9-landing-elon-musk-wont-fly |title=SpaceX’s 'reusable' Falcon 9 rocket won’t fly again, Elon Musk says |work=[[The Verge]] |first=Sean |last=O'Kane |date=December 21, 2015 |access-date=December 23, 2015}}</ref> Rather, the rocket was moved a few miles north to the SpaceX hangar facilities at [[Launch pad 39A]], recently refurbished by SpaceX at the adjacent [[Kennedy Space Center]], where it was inspected before being used on January 15, 2016, to conduct a [[static fire]] test on its original launchpad, [[Launch Complex 40]].<ref>{{Cite news |url=http://www.universetoday.com/126837/spacex-test-fires-recovered-falcon-9-booster-major-step-reusable-rockets/ |title=SpaceX Test Fires Recovered Falcon 9 Booster in Major Step To Reusable Rockets - Universe Today |date=January 16, 2016 |newspaper=Universe Today |language=en-US |access-date=January 28, 2017}}</ref> This test aimed to assess the health of the recovered booster and the capability of this rocket design to fly repeatedly in the future.<ref name=f20-static-fire>{{cite web |url=http://spaceflight101.com/returned-falcon-9-booster-fires-up-for-static-fire-test/ |work=Spaceflight 101 |title=Returned falcon 9 booster fires up for static fire test |date=January 15, 2016 |accessdate=January 18, 2016}}</ref><ref name=nsf20151231/> The tests delivered good overall results except for one of the outer engines experiencing thrust fluctuations.<ref name=f20-static-fire /> Elon Musk reported that this may have been due to debris ingestion.<ref>{{cite news |title=SpaceX Tests Recovered Falcon 9 Stage and Prepares for Next Launch |url=http://spacenews.com/spacex-tests-recovered-falcon-9-stage-and-prepares-for-next-launch/ |date=January 15, 2016 |accessdate=January 15, 2016}}</ref>
[[File:First stage of Jason-3 rocket (24423604506).jpg|thumb|First stage of [[Falcon 9 Flight 21]] descending over the floating landing platform, January 17, 2016, immediately prior to a soft touchdown followed by [[deflagration]] of the rocket after a landing leg failed to latch, causing the rocket to tip over.]]
==== Near-misses on the oceans ====
[[Falcon 9 Flight 21]] launched the [[Jason-3]] satellite on January 17, 2016, and attempted to land on the [[autonomous spaceport drone ship|floating platform]] ''Just Read the Instructions'',<ref name=nbc20160107>
{{cite news |url=http://www.nbcnews.com/tech/innovation/spacex-plans-drone-ship-rocket-landing-jan-17-launch-n492471 |title=SpaceX Plans Drone Ship Rocket Landing for Jan. 17 Launch |publisher=[[NBC News]] |first=Devin |last=Coldewey |date=January 7, 2016 |access-date=January 8, 2016}}</ref> located for the first time about {{convert|200|mi|km}} out in the [[Pacific Ocean]].
<!-- press conference, Hans Koenigsmann speaking for SpaceX: they are not attempting the landing on the land landing site at VAFB SLC4W because they have not yet received approval from the regulatory authorities; will find a secondary source before adding to the article prose... --><!-- HK: they may try to give video coverage of the landing, but unsure they can do it from over the horizon, satellite links, etc. -->
Approximately 9 minutes into the flight, the live video feed from the drone ship went down due to the losing its lock on the uplink satellite.
The vehicle landed smoothly onto the vessel but one of the four landing legs failed to lock properly, reportedly due to ice from the heavy pre-launch [[fog]] preventing a lockout [[collet]] from latching.<ref name=sfn20160118>
{{cite web |title=SpaceX narrowly misses booster landing at sea |work=Spaceflight Now |url=https://spaceflightnow.com/2016/01/18/spacex-narrowly-misses-booster-landing-at-sea/ |date=January 18, 2016 |access-date=January 18, 2016 |first=Stephen |last=Clark}}</ref>
Consequently the booster fell over shortly after touchdown and was destroyed in a [[deflagration]] upon impact with the pad.<ref name=gw20160117>
{{cite news |last=Boyle |first=Alan |url=http://www.geekwire.com/2016/spacex-launches-jason-3-satellite-then-tries-landing-falcon-9-rocket-at-sea/ |title=SpaceX rocket launches satellite, but tips over during sea landing attempt |work=GeekWire |date=January 17, 2016 |accessdate=January 18, 2016}}</ref><ref name=rud>{{cite web |url=https://www.instagram.com/p/BAqirNbwEc0/ |title=Flight 21 landing and breaking a leg |work=Instagram |first=Elon |last=Musk |author-link=Elon Musk |date=January 17, 2016}}</ref>
[[Falcon 9 Flight 22|Flight 22]] was carrying a heavy payload of {{convert|5271|kg|sigfig=2}} to [[geostationary transfer orbit]] (GTO). This was heavier than previously advertised maximum lift capacity to GTO being made possible by going slightly [[subsynchronous orbit|subsynchronous]]. Following delays caused by failure of [[Falcon 9 Flight 19|Flight 19]] SpaceX agreed to provide extra thrust to the [[SES-9]] satellite to take it [[supersynchronous orbit|supersynchronous]].<ref name=sfn20160224>
{{cite news |last=Clark |first=Stephen |url=http://spaceflightnow.com/2016/02/24/falcon-9-rocket-to-give-ses-9-telecom-satellite-an-extra-boost/ |title=Falcon 9 rocket to give SES 9 telecom satellite an extra boost |work=Spaceflight Now |date=February 24, 2016 |accessdate=March 7, 2016 |quote=''SES’s contract with SpaceX called for the rocket to deploy SES 9 into a “sub-synchronous” transfer orbit with an apogee around 16,155 miles (26,000 kilometers) in altitude. Such an orbit would require SES 9 to consume its own fuel to reach a circular 22,300-mile-high perch, a trek that Halliwell said was supposed to last 93 days. The change [SpaceX offered] in the Falcon 9’s launch profile will put SES 9 into an initial orbit with an apogee approximately 24,419 miles (39,300 kilometers) above Earth, a low point 180 miles (290 kilometers) up, and a track tilted about 28 degrees to the equator''}}</ref>
As a result of these factors, there was little propellant left to execute a full reentry and landing test with normal margins. Consequently the Falcon 9 first stage followed a [[ballistic trajectory]] after separation and re-entered the atmosphere at high velocity, making it less likely to land successfully.<ref name=sxPressKit20160223>{{cite web |url=http://www.spacex.com/sites/spacex/files/spacex_ses9_press_kit_final.pdf |format=PDF |title=SES-9 Mission |work=Press Kit |publisher=SpaceX |date=February 23, 2016 |accessdate=February 24, 2016 |quote=This mission is going to a Geostationary Transfer Orbit. Following stage separation, the first stage of the Falcon 9 will attempt an experimental landing on the “Of Course I Still Love You” droneship. Given this mission’s unique GTO profile, a successful landing is not expected.}}</ref><ref name=sfn20160224/> The [[atmospheric re-entry]] and controlled descent were successful despite the higher aerodynamical constraints on the first stage due to extra speed. However the rocket was moving too fast and was destroyed when it collided with the drone ship. SpaceX collected valuable data on the extended flight envelope required to recover boosters from GTO missions.
==== Landings at sea ====
{{main| Autonomous spaceport drone ship | SpaceX CRS-8 | JCSAT-2B}}
[[File:CRS-8 (26239020092).jpg|thumb|right|First stage of Falcon 9 Flight 23 landed on autonomous droneship]]
Starting in January 2015, SpaceX positioned stable floating platforms a few hundred miles off the coast along the rocket trajectory; those transformed barges were called [[autonomous spaceport drone ship]]s.<ref name=nsf20141124>{{cite news |last1=Bergin |first1=Chris |title=SpaceX's Autonomous Spaceport Drone Ship ready for action |url=http://www.nasaspaceflight.com/2014/11/spacex-autonomous-spaceport-drone-ship/ |accessdate=24 November 2014 |work=NasaSpaceFlight.com |date=24 November 2014}}</ref> On April 8, 2016, Falcon 9 Flight 23, the third flight of [[Falcon 9 full thrust|the full-thrust version]], delivered the [[SpaceX CRS-8]] cargo on its way to the [[International Space Station]] while the [[Falcon 9 booster B1021|first stage]] conducted a boostback and re-entry maneuver over the Atlantic ocean. Nine minutes after liftoff, the booster landed vertically on the drone ship ''[[Of Course I Still Love You]]'', 300 km from the Florida coastline, achieving a long-sought-after milestone for the SpaceX reusability development program.<ref name=flight23>{{cite news |url=http://phenomena.nationalgeographic.com/2016/04/08/spacex-rocket-makes-spectacular-landing-on-drone-ship/ |title=SpaceX Rocket Makes Spectacular Landing on Drone Ship |publisher=[[National Geographic Society|National Geographic]] |first=Nadia |last=Drake |date=April 8, 2016 |accessdate=April 8, 2016 |quote=To space and back, in less than nine minutes? Hello, future.}}</ref>
A second successful drone ship landing occurred on May 6, 2016, with the next flight which launched [[JCSAT-14]] to GTO. This second landing at sea was more difficult than the previous one because the booster at separation was traveling about {{convert|8350|km/h|abbr=on}} compared to {{convert|6650|km/h|abbr=on}} on the CRS-8 launch to [[low Earth orbit]].<ref>[https://www.youtube.com/watch?v=7pUAydjne5M You tube JCSat 14 hosted webcast]</ref><ref>[https://www.youtube.com/watch?v=7pUAydjne5M You tube CRS8 hosted webcast]</ref> Pursuing their experiments to test the limits of the flight envelope, SpaceX opted for a shorter landing burn with three engines instead of the single-engine burns seen in earlier attempts; this approach consumes less fuel by leaving the stage in free fall as long as possible and decelerating more sharply, thereby minimizing the amount of energy expended to counter gravity.<ref name=musk-tweet-20160506>
{{cite tweet |user=elonmusk |author-link=Elon Musk |number=728462267893698561 |date=May 6, 2016 |access-date=May 8, 2016 |title=Yeah, this was a three engine landing burn, so triple deceleration of last flight. That's important to minimize gravity losses.}}</ref> Elon Musk indicated this first stage may not be flown again instead being used as a life leader for ground tests to confirm others are good.<ref>[http://www.floridatoday.com/story/tech/science/space/spacex/2016/05/16/landed-spacex-rocket-suffered-max-damage/84454230/ Florida Today Landed spacex rocket suffered max damage]</ref>
A third successful landing followed on 27 May, again following deceleration from the high speed required for a GTO launch. The landing crushed a "crush core" in one leg, leading to a notable tilt to the stage as it stood on the drone ship.<ref name="space.com"/>
==== Routine procedure ====
{{Main|List of Falcon 9 and Falcon Heavy launches}}
Over the subsequent missions, landing of the first stage gradually became a routine procedure, and since January 2017 SpaceX ceased to refer to their landing attempts as "experimental". Low-energy missions to the [[ISS]] fly back to the launch site and land at [[Landing Zone 1|LZ-1]], whereas more demanding satellite missions land on drone ships a few hundred miles downrange. Occasional missions with heavy payloads, such as [[EchoStar 23]], do not attempt to land, flying in [[Expendable launch system|expendable]] configuration without fins and legs.
Further successful landings occurred:
* on the LZ-1 ground pad: [[CRS-9]] on 18 July 2016, [[CRS-10]] on 19 February 2017, [[NROL]]-76 on 1 May, [[CRS-11]] on 3 June, [[CRS-12]] on 14 August, [[Boeing X-37B|Boeing X-37B OTV-5]] on 7 September, [[CRS-13]] on 15 December, and [[Zuma (satellite)|Zuma]] on 8 January 2018.<!-- UPDATE after each recovery on land -->
* on drone ships: [[JCSAT-16]] on 14 August 2016, [[Iridium NEXT]]-1 on 14 January 2017, [[SES-10]] on 30 March and [[BulgariaSat-1]] on 23 June (first and second recoveries of re-flown boosters), [[Iridium NEXT]]-2 on 25 June, [[Formosat-5]] on 24 August, [[Iridium NEXT]]-3 on 9 October, [[SES-11]]/[[EchoStar 105]] on 11 October, and [[Koreasat 5A]] on 30 October 2017.<!-- UPDATE after each recovery at sea -->
==== Future tests ====
{{main article| List of Falcon 9 first-stage boosters | List of Falcon 9 and Falcon Heavy launches#Future launches}}
During 2016 and 2017, SpaceX has recovered a number of first stages to both land and drone ships, helping them optimize the procedures needed to re-use the boosters rapidly. In January 2016 Elon Musk estimated the likelihood of success at 70 percent for all landing attempts in 2016, hopefully rising to 90 percent in 2017; he also cautioned that we should expect "a few more RUDs" (''Rapid Unscheduled Disassembly'', Musk's euphemism to denote destruction of the vehicle on impact).<ref>{{cite tweet |user=elonmusk |author-link=Elon Musk |number=689299216607232000 |date=January 19, 2016 |title=My best guess for 2016: ~70% landing success rate (so still a few more RUDs to go), then hopefully improving to ~90% in 2017}}</ref> Musk's prediction was vindicated, as 5 out of 8 flown boosters ({{percent|5|8}}) were recovered in 2016, and 14 out of 14 ({{percent|14|14}}) in 2017. Three GTO missions for heavy payloads ([[EchoStar#Satellite fleet|EchoStar 23]] in March 2017, [[Inmarsat-5 F4]] in May 2017 and [[Intelsat 35e]] in July 2017) were flown in an [[expendable launch system|expendable]] configuration, not equipped for landing. One booster which could have been recovered was intentionally flown without legs and left to sink after a soft touchdown in the ocean (booster B1036 for the [[Iridium NEXT]] 31–40 mission in December 2017).
Since late 2017, incremental testing with refinements to the fairing recovery design have been conducted. SpaceX has indicated that they expected to recover an intact fairing in 2017, and to fly a recovered fairing in 2018.<ref name=issR&Dconf20170719-14:15/> {{As of|December 2017}}, no official information on progress in the fairing recovery process was available.
=== First-stage reuse ===
{{As of|2018|02|06}}, SpaceX had [[List of Falcon 9 first-stage boosters|recovered 17 first-stage boosters from previous missions]], of which six were recovered twice, yielding a total 23 landings. In 2017, SpaceX flew a total of 5 missions out of 20 with re-used boosters ({{percent|5|20}}). In total, eight boosters have been re-flown {{as of|February 2018|lc=y}}.
On July 28, 2016, the first stage from the [[JCSAT-2B]] mission was successfully test-fired for a full duration at the SpaceX McGregor facility.<ref>{{cite video |url=https://www.youtube.com/watch?v=SZQY902xQcw |title=Landed Falcon 9 First Stage Test Firing |publisher=SpaceX |date=July 28, 2016}}</ref> The first reuse attempt occurred on 30 March 2017<ref name="SpaceflightNowSchedule">{{Cite web|url=https://spaceflightnow.com/2017/03/30/ses-10-mission-status-center/|title=Live coverage: SpaceX aims for Thursday launch of previously-flown rocket - Spaceflight Now|last=|first=|date=|website=|access-date=March 31, 2017}}</ref> with the launch of [[SES-10]],<ref>{{cite news |url=http://www.latimes.com/business/la-fi-spacex-rocket-20160829-snap-story.html |title=SpaceX signs first customer for launch of a reused rocket |newspaper=[[Los Angeles Times]] |first=Samantha |last=Masunaga |date=August 30, 2016}}</ref> resulting in a successful flight and second landing of the [[Falcon 9 booster B1021|B1021 first stage]] recovered from the [[SpaceX CRS-8|CRS-8]] mission of April 2016.<ref>{{cite news |url=http://www.satellitetoday.com/nextspace/2016/08/30/ses-becomes-first-reusable-rocket-customer-spacex/ |title=SES Becomes First Reusable Rocket Customer for SpaceX |work=Via Satellite |first=Caleb |last=Henry |date=August 30, 2016}}</ref> Another reflight succeeded in June 2017 with [[BulgariaSat-1]] riding the [[B1029]] booster from the January 2017 [[Iridium NEXT]] mission.<ref name=nsf-20170623>{{cite news |url=https://www.nasaspaceflight.com/2017/06/spacex-falcon-9-second-flight-bulgariasat-1-mission/ |title=SpaceX Falcon 9 success with second flight involving BulgariaSat-1 mission |work=[[NASASpaceFlight.com]] |first=William |last=Graham |date=June 23, 2017 |access-date=June 25, 2017}}</ref> Booster B1031 flew the [[CRS-10]] mission to the [[ISS]] in February 2017 and helped loft communications satellite [[SES-11]] to [[geostationary orbit]] in October 2017. Boosters B1035 and B1036 were flown twice each for the same customer, B1035 for [[NASA]] missions [[CRS-11]] and [[CRS-13]] in June and December 2017, and B1036 for two batches of 10 [[Iridium NEXT]] satellites, also in June and December 2017. B1032 was re-used for [[GovSat-1]] in January 2018 after [[NROL-76]] in May 2017. Finally, B1023 and B1025 were re-used as side boosters on the [[Falcon Heavy test flight]] in February 2018.
SpaceX spent four months refurbishing the first booster to be re-used, [[B1021]], and launched it again after approximately one year.<ref>{{cite news|url= https://spaceflightnow.com/2017/03/27/hotfire-test-completed-ahead-of-milestone-falcon-9-launch-thursday/ |work= Spaceflight Now |title= Hotfire test completed ahead of milestone Falcon 9 launch Thursday |first= Stephen |last= Clark |date= 2017-03-27 |accessdate= 2017-04-01 }}</ref> The second booster to be flown again, [[B1029]], was refurbished in "only a couple of months"<ref name=sir-20170626 /> and re-launched after five months.<ref name=nsf-20170623 /> Elon Musk has stated a goal to turn around a first stage within 24 hours before the end of 2017,<ref>{{cite news |url= http://www.telegraph.co.uk/news/2017/03/31/spacex-makes-history-successfully-launching-first-recycled-rocket/ |newspaper= [[The Daily Telegraph]] |agency= [[Reuters]] |title= SpaceX makes history by successfully launching first recycled rocket booster |date= 2017-03-31 |accessdate= 2017-04-01}}</ref> but that did not happen.
Boosters [[B1019]] and [[B1021]] were retired and put on display. [[B1029]] was also retired after the [[BulgariaSat-1]] mission.<ref>{{cite web|title=List of Falcon 9 first-stage boosters|url=https://en.wikipedia.org/wiki/List_of_Falcon_9_first-stage_boosters|accessdate=26 November 2017}}</ref>{{Better source|reason=per WP:CIRCULAR|date=February 2018}} B1023, B1025, B1031 and B1035 were recovered a second time, while B1032 and B1036 was voluntarily sunk at sea after a soft ocean touchdown.
=== Fairing reuse ===
On March 30, 2017 as part of the [[SES-10]] mission, SpaceX for the first time performed a controlled landing of the payload fairing, using thrusters to properly orient the fairing during atmospheric reentry and a steerable parachute to achieve an intact splashdown.<ref name=verge20170330/><ref name=sn20170330/> With the aim of full reuse, it is planned that fairings will land on a structure jokingly described by Musk as a "floating bouncy-castle".<ref name=floridatoday_26216836069515264/>
With successive tests and refinements on a number of flights, intact fairing recovery was stated as a goal for 2017, with reflight of a recovered fairing planned in 2018.<ref name=issR&Dconf20170719-14:15/>
The "bouncy castle" idea has been superseded by a net strung between large arms. This system, installed on ''Mr. Steven'' (a fast [[platform supply vessel]] equipped with [[dynamic positioning]] systems), was tested on the launch of the [[Paz (satellite)|Paz]] satellite from [[Vandenberg Air Force Base]] [[Vandenberg AFB Space Launch Complex 4#SLC-4E|Space Launch Complex 4E]] in February 2018.<ref name=techcrunch20180220>{{cite news|last1=Etherington|first1=Darrell|title=SpaceX to use a net boat called ‘Mr. Steven’ to recover next rocket fairing|url=https://techcrunch.com/2018/02/20/spacex-to-use-a-net-boat-called-mr-steven-to-recover-next-rocket-fairing/|accessdate=February 20, 2018|work=TechCrunch|date=February 20, 2018|language=en}}</ref><ref name="nsf-20180225">{{cite news|last1=Baylor|first1=Michael|title=SpaceX’s Mr. Steven, the FSV fairing catcher – NASASpaceFlight.com|url=https://www.nasaspaceflight.com/2018/02/spacexs-mr-steven-fsv-fairing-catcher/|accessdate=February 26, 2018|work=NASASpaceFlight.com|date=February 25, 2018}}</ref> This mission also introduced a version 2 fairing, explicitly designed to "improve survivability for post-launch recovery attempts, and to be reusable on future missions".<ref name="nsf-20180220">{{cite news|last1=Graham|first1=William|title=SpaceX Falcon 9 set for PAZ launch with Starlink demo and new fairing – NASASpaceFlight.com|url=https://www.nasaspaceflight.com/2018/02/spacex-falcon-9-paz-launch-starlink-demo-new-fairing/|accessdate=February 21, 2018|work=NASASpaceFlight.com|date=February 20, 2018}}</ref>. This recovery attempt was not fully successful; the fairing missed the boat by a few hundred meters but landed intact in the water<ref>{{cite web|last1=Musk|first1=Elon|title=Missed by a few hundred meters, but fairing landed intact in water. Should be able catch it with slightly bigger chutes to slow down descent.|url=https://twitter.com/elonmusk/status/966692641533390848|publisher=Twitter|accessdate=22 February 2018|language=en|date=2018}}</ref> before being recovered and taken back to port.<ref name="nsf-20180225" />
=== Second-stage reuse ===
SpaceX also intends to experiment with second stage recovery on selected Falcon 9 flights. Together with the recovery of the payload fairing, this achievement would eventually enable full reusability of the rocket family.<ref name=issR&Dconf20170719-14:15/>
== Operational flow ==
In the first year of successful stage return from the experimental test flights, SpaceX performed ''[[ad hoc]]'' and flight-specific evaluation and component testing on each successfully landed stage. Stages were processed and initially evaluated in either launch hangars, or for Cape Canaveral landings, in the new hangar SpaceX recently completed at [[Kennedy Space Center Launch Complex 39]]. Returned rocket parts have also been transported to [[SpaceX Hawthorne]] and [[SpaceX McGregor]] for engineering evaluation and testing.
In February 2017, after eight rocket cores had successfully landed — seven of them having launched from Cape Canaveral — SpaceX announced plans to expand their physical facilities to process and refurbish rockets. They will do so in both leased space and in a new building to be built in [[Port Canaveral]], [[Florida]], near the location where the Atlantic [[Autonomous Spaceport Drone Ship]] is berthed, and where stages that land on the [[East Coast of the United States|east-coast]] droneship are now removed from the ship.<ref name=ft20160824>
{{cite news |url=http://www.floridatoday.com/story/tech/science/space/spacex/2016/08/24/spacex-lease-building-port-canaveral-build-another-one/89230076/ |title=SpaceX to lease building at Port Canaveral, build another one |work=[[Florida Today]] |date=August 24, 2016 |accessdate=August 24, 2016}}</ref>
== See also ==
{{Portal|Spaceflight}}
* [[Blue Origin]] [[New Shepard]], a sub-orbital VTVL system
== References ==
{{Reflist|30em}}
== External links ==
{{Commons category|Grasshopper (rocket)}}
*
* [https://www.youtube.com/watch?v=9ZDkItO-0a4 Video of 8th and final low-altitude Grasshopper v1.0 test flight], to {{convert|744|m|mile|abbr=off|sp=us}}, October 7, 2013.
* [http://www.space.com/23230-spacex-falcon9-reusable-rocket-milestone.html Low-resolution photograph of the Falcon 9 booster controlled-descent test on September 29, 2013, just moments before impacting the Atlantic ocean.]
* [https://www.youtube.com/watch?v=0UjWqQPWmsY Video of Falcon 9 Reusable Development vehicle no. 1 (F9R Dev1) 1st test flight], to {{convert|250|m|mile|abbr=off|sp=us}}, hovering and then landing just next to the launch stand, April 17, 2014.
* Video of CRS-3 booster stage landing test, April 2014: [http://www.spacex.com/news/2014/04/29/first-stage-landing-video low quality, corrupted data] and [https://www.youtube.com/watch?v=CjZ33C9JZTM higher quality, after video frames recovered by open-source recovery effort by NSF team].
* On-board camera video of ORBCOMM Mission-1 booster stage landing test: [https://www.youtube.com/watch?v=CQnR5fhCXkQ Falcon 9 First Stage Return : ORBCOMM Mission], SpaceX-released video of the controlled descent test, July 2014.
* Chase-plane camera video of ORBCOMM Mission-1 booster stage landing test: [https://www.youtube.com/watch?v=uIlu7szab5I Falcon 9 First Stage Reentry Footage from Plane ], SpaceX-released video of the controlled descent test, released August 14, 2014.
* [https://news.yahoo.com/novel-spacex-falcon-mission-blasts-off-florida-102343900.html SpaceX rocket nails launch but narrowly misses landing test], Reuters, Irene Klotz, January 10, 2015.
{{SpaceX}}
{{Reusable launch systems}}
[[Category:Engineering projects]]
[[Category:Spaceflight technologies]]
[[Category:SpaceX]]
[[Category:Articles containing video clips]]' |
New page wikitext, after the edit (new_wikitext) | '{{Good article}}
{{Use mdy dates|date=March 2017}}
{{Use American English|date=December 2013}}
{{Infobox project
| name = SpaceX reusable launch system development program
| logo =
| image = File:ORBCOMM-2 (23282658734).jpg
| caption = [[Falcon 9 Flight 20]]'s first stage landing vertically on solid ground in December 2015
| website = <!-- {{URL|example.com}} -->
| mission_statement =
| commercial = Yes
| type = Privately funded technology development
| products = [[Falcon 9]], [[Falcon Heavy]], [[Interplanetary Transport System]]
| location = Various
| owner = [[SpaceX]]
| founder = [[Elon Musk]]
| funding =
| established = Publicly announced 2011
| disestablished = <!-- {{End date|YYYY|MM|DD}} -->
| current_status = Active
}}
The '''SpaceX reusable launch system development program''' is a [[private spaceflight|privately funded]] program to develop a set of new technologies for an [[Orbital spaceflight|orbital]] [[spacecraft|launch system]] that may be [[reusable launch vehicle|reused]] many times in a manner similar to the reusability of [[aircraft]]. The company [[SpaceX]] is developing the technologies over a number of years to facilitate full and rapid reusability of space [[launch vehicle]]s. The project's long-term objectives include returning a launch vehicle [[multistage rocket|first stage]] to the launch site in minutes and to return a second stage to the [[launch pad]] following orbital realignment with the launch site and [[atmospheric entry|atmospheric reentry]] in up to 24 hours. SpaceX's long term goal is that both stages of their orbital launch vehicle<!-- they are only working on the first stage with the Falcon 9; will do both stages of the Mars Colonial Transporter --> will be designed to allow reuse a few hours after return.<ref name="pm20120207">{{cite news |url=http://www.popularmechanics.com/science/space/rockets/elon-musk-on-spacexs-reusable-rocket-plans-6653023 |title=Elon Musk on SpaceX's Reusable Rocket Plans |work=Popular Mechanics |last=Simberg |first=Rand |date=February 8, 2012 |accessdate=February 7, 2012}}</ref>
The program was publicly announced in 2011. SpaceX first achieved a [[Falcon 9 Flight 20|successful landing and recovery of a first stage]] in December 2015. The [[SES-10|first re-flight of a landed first stage]] occurred in March 2017<ref name=sn20170330/> with the second occurring in June 2017, that one only five months after the maiden flight of the booster.<ref name=sir-20170626 /> The third attempt occurred in October 2017 with the [[SES-11]]/[[EchoStar-105]] mission. Second flights of refurbished first stages then became routine.
The [[reusable launch system]] technology was developed and initially used for the first stages of the [[Falcon (rocket family)|Falcon family]] of rockets.<ref name=sn20141024/> After stage [[Separation event|separation]], the return process involves flipping the booster around, an optional boostback burn to reverse its course, a reentry burn, controlling direction to arrive at the landing site and a landing burn to effect the final low-altitude deceleration and touchdown.
SpaceX is intending to develop technology to extend reusable flight hardware to second stages, a more challenging engineering problem because the vehicle is travelling at [[Orbital speed#Tangential velocities at altitude|orbital velocity]],<ref name=nsf20160927/><ref name=sn20141024/><ref name=nsf20140307/>
which is considered paramount to the plans Elon Musk is championing to enable the [[Colonization of Mars|settlement of Mars]]. It is thus planned to be developed for all of the flight hardware for the new SpaceX vehicles planned to transit to Mars,<ref name=gq20151212/><ref name=spacex-itspresentation201609/> with initial test flights expected no earlier than 2020.<ref name=nsf20160927/> SpaceX may also experiment with second stage recovery on a few select Falcon 9 flights<ref name=issR&Dconf20170719-14:15/> or Falcon Heavy flights.<ref name=musk20170331>
{{cite web |url=https://twitter.com/elonmusk/status/847882289581359104 |title=Considering trying to bring upper stage back on Falcon Heavy demo flight for full reusability |last=Musk|first=Elon |publisher=SpaceX |date=2017-03-31 }}</ref>
{{TOC limit|4}}
== History ==
[[File:Falcon rocket family4.svg|thumb|400px|right|From left to right, [[Falcon 1]], [[Falcon 9 v1.0]], three versions of [[Falcon 9 v1.1]], three versions of [[Falcon 9 Full Thrust|Falcon 9 v1.2 (Full Thrust)]], and [[Falcon Heavy]]. The SpaceX reusable rocket technology is being developed for both Falcon 9 v1.2 and Falcon Heavy.]]
SpaceX initially attempted to land the first stage of the [[Falcon 1#Reusability|Falcon 1 by parachute]], however the stage did not survive the re-entry into the atmosphere. They continued to experiment with parachutes on the earliest [[Falcon 9]] flights after 2010. SpaceX subsequently switched its focus to developing a powered descent landing system.<ref name=nsf20170330>
{{cite news |last=Graham|first=William |url=https://www.nasaspaceflight.com/2017/03/spacex-historic-falcon-9-re-flight-ses-10/ |title=SpaceX conducts historic Falcon 9 re-flight with SES-10 – Lands booster again |work=[[NASASpaceFlight.com]] |date=2017-03-30 |accessdate=2017-05-27 |quote='The earliest Falcon 9 launches carried parachutes which were to have been used to recover the first stage. However, this was abandoned due to the stage disintegrating during reentry, before the parachutes could be deployed. Instead, SpaceX began to investigate using the stage’s engines to make a powered descent and landing. Alongside this, an improved Falcon 9 vehicle, the Falcon 9 v1.1, was developed.' }}</ref>
The broad outline of the reusable launch system was first publicly described in September 2011. SpaceX said it would attempt to develop powered descent and recovery of both Falcon 9 stages{{mdash}}a fully vertical takeoff, vertical landing ([[VTVL]]) rocket. The company produced a [[Computer animation|computer-animated video]] depicting a notional view of the first stage returning tail-first for a powered descent and the second stage with a heat shield, reentering head first before rotating for a powered descent.<ref name="wp20110929">{{cite video |url=https://www.youtube.com/watch?v=RkvLQdzZRFo |title=SpaceX Chief Details Reusable Rocket |agency=Associated Press |work=Washington Post |date=September 29, 2011 |accessdate=April 9, 2016}}</ref><ref name="sdc20110930">{{cite news |url=http://www.space.com/13140-spacex-private-reusable-rocket-elon-musk.html |title=SpaceX Unveils Plan for World's First Fully Reusable Rocket |newspaper=Space.com |last=Wall |first=Mike |date=September 30, 2011 |accessdate=October 11, 2011}}</ref><ref name="SpaceX Video from SpaceX. com">{{cite web |url=http://www.spacex.com/assets/video/spacex-rtls-green.mp4 |title=Falcon 9 Return to Launch Site |format=video |work=SpaceX.com |archiveurl=https://web.archive.org/web/20111011221641/http://www.spacex.com/assets/video/spacex-rtls-green.mp4 |archivedate=October 11, 2011}}</ref><ref name="npc20110929">{{cite AV media |url=https://www.youtube.com/watch?v=xrVD3tcVWTY |title=National Press Club: The Future of Human Spaceflight |medium=video |work=NPC video repository |date=September 29, 2011 |people=Mark Hamrick, Elon Musk |publisher=National Press Club |quote=(@18:15 It is a very tough engineering problem—and it wasn't something that I thought, wasn't sure it could be solved for a while. But then, just relatively recently, in the last 12 months or so, I've come to the conclusion that it can be solved. And SpaceX is going to try to do it. Now, we could fail. I am not saying we are certain of success here, but we are going to try to do it. And we have a design that, on paper, doing the calculations, doing the simulations, it does work. Now we need to make sure that those simulations and reality agree, because generally when they don't, reality wins. So that's to be determined.)}}</ref><!-- ←the original source was http://www.c-span.org/Events/National-Press-Club-The-Future-of-Human-Spaceflight/10737424486/ |title=National Press Club: The Future of Human Spaceflight |work=C-SPAN.org |date=September 29, 2011 --- but that link has gone dead. Found another copy on the NPC video repository on YouTube --> In September 2012, SpaceX began flight tests on a prototype reusable first stage with the suborbital [[Grasshopper (rocket)|Grasshopper rocket]].<ref name="cl20121224" /> Those tests continued into 2014, including testing of a second and larger prototype vehicle, [[F9R Dev1]].
News of the Grasshopper test rocket had become public a few days earlier, when the [[Federal Aviation Administration|US Federal Aviation Administration]] released a [[National Environmental Policy Act|draft Environmental Impact Assessment]] for the SpaceX Test Site in Texas, and the space media had reported it.<ref name="faa20110922">{{cite web |url=http://www.faa.gov/about/office_org/headquarters_offices/ast/media/20110922%20spacex%20grasshopper%20draft%20ea.final.pdf |title=Draft Environmental Assessment for Issuing an Experimental Permit to SpaceX for Operation of the Grasshopper Vehicle at the McGregor Test Site, Texas |publisher=Federal Aviation Administration |date=September 22, 2011 |accessdate=November 21, 2013}}</ref><ref name="satspot20110926" /> In May 2012, SpaceX obtained a set of atmospheric test data for the recovery of the Falcon 9 first stage based on 176 test runs in the [[NASA]] [[Marshall Space Flight Center]] [[wind tunnel]] test facility. The work was contracted for by SpaceX under a reimburseable [[Space Act Agreement]] with NASA.<ref name="sn20120528">{{cite news |url=http://www.spacenews.com/article/nasa-finishes-wind-tunnel-testing-falcon-9-1st-stage |title=NASA Finishes Wind-tunnel Testing of Falcon 9 1st Stage |work=Space News |date=May 28, 2012 |accessdate=June 26, 2012}}</ref>
In 2012, it was projected that the first-stage separation of a [[Falcon 9R|reusable Falcon 9]] rocket would occur at a velocity of approximately {{nowrap|2.0 km/s}} {{nowrap|(6,500 km/h; 4,100 mph; Mach 6)}} rather than the {{nowrap|3.4 km/s}} {{nowrap|(11,000 km/h; 7,000 mph; Mach 10)}} for an expendable Falcon 9, to provide the residual fuel necessary for the deceleration and turnaround maneuver and the controlled descent and landing.<ref name="pm20120207" />
In November 2012, CEO [[Elon Musk]] announced SpaceX's plans to build a second, much larger, [[SpaceX super-heavy lift launch vehicle|reusable rocket system]], this one to be powered by [[LOX]]/[[liquid methane|methane]] rather than LOX/[[RP-1]] used on Falcon 9 and Falcon Heavy. The new system was to be "an evolution of SpaceX's Falcon 9 booster", and SpaceX reiterated their commitment to develop a breakthrough in vertical landing technology.<ref name="sdc20121123">{{cite news |url=http://www.space.com/18596-mars-colony-spacex-elon-musk.html |title=Huge Mars Colony Eyed by SpaceX Founder Elon Musk |work=Space.com |last=Coppinger |first=Rod |date=November 23, 2012 |accessdate=November 25, 2012 |quote=much bigger [than Falcon 9], but I don’t think we’re quite ready to state the payload. We’ll speak about that next year.}}</ref> By the end of 2012, the demonstration test vehicle, Grasshopper, had made three VTVL test flights{{mdash}}including a 29-second hover flight to {{convert|40|m|sp=us}} on December 17, 2012.<ref name="cl20121224">{{cite news |url=http://cosmiclog.nbcnews.com/_news/2012/12/23/16114180-spacex-launches-its-grasshopper-rocket-on-12-story-high-hop-in-texas |title=SpaceX launches its Grasshopper rocket on 12-story-high hop in Texas |work=NBC News{{\}}Cosmic Log |last=Boyle |first=Alan |date=December 24, 2012 |accessdate=December 25, 2012}}</ref> In early March 2013, SpaceX successfully tested Grasshopper for a fourth time when it flew to an altitude of over {{convert|80|m|sp=us}}.<ref name=nsj20130309/>
In March 2013, SpaceX announced that it would instrument and equip subsequent Falcon 9 first-stages as controlled descent test vehicles, with plans for over-water propulsively-decelerated simulated landings beginning in 2013, with the intent to return the vehicle to the launch site for a powered landing{{mdash}}possibly as early as mid-2014.<ref name="pa20130328">{{cite news |url=http://www.parabolicarc.com/2013/03/28/dragon-post-mission-press-conference-notes/ |title=Dragon Post-Mission Press Conference Notes |work=Parabolic Arc |last=Messier |first=Doug |date=March 28, 2013 |accessdate=March 30, 2013 |quote=Q. What is strategy on booster recover? Musk: Initial recovery test will be a water landing. First stage continue in ballistic arc and execute a velocity reduction burn before it enters atmosphere to lessen impact. Right before splashdown, will light up the engine again. Emphasizes that we don’t expect success in the first several attempts. Hopefully next year with more experience and data, we should be able to return the first stage to the launch site and do a propulsion landing on land using legs. Q. Is there a flight identified for return to launch site of the booster? Musk: No. Will probably be the middle of next year.}}</ref> The April 2013 draft [[Environmental impact statement|Environmental Impact Statement]] for the proposed [[SpaceX South Texas Launch Site]] includes specific accommodations for return of the Falcon 9 first-stage boosters to the launch site.<ref name="faa201304v1">{{cite report|url=http://1.usa.gov/YtxBzo |title=Draft Environmental Impact Statement: SpaceX Texas Launch Site |publisher=Federal Aviation Administration{{\}}Office of Commercial Space Transportation |last=Nield |first=George C. |volume=1 |date=April 2013 |deadurl=yes |archiveurl=https://web.archive.org/web/20131207085028/http://www.faa.gov/about/office_org/headquarters_offices/ast/environmental/nepa_docs/review/documents_progress/spacex_texas_launch_site_environmental_impact_statement/media/SpaceX_Texas_Launch_Site_Draft_EIS_V1.pdf |archivedate=December 7, 2013 |df= }}</ref> Elon Musk first publicly referred to the reusable Falcon 9 as the [[Falcon 9-R]] in April 2013.<ref name="musk20130428" />
In September 2013, SpaceX successfully relit three engines of a spent booster on an orbital launch, and the booster re-entered the atmosphere at hypersonic speed without burning up.<ref name=fp20131209/> With the data collected from the first flight test of a booster-controlled descent from high altitude, coupled with the technological advancements made on the Grasshopper low-altitude landing demonstrator, SpaceX announced it believed it was ready to test a full land-recovery of a booster stage.<ref name=pm20130930/> Based on the positive results from the first high-altitude flight test, SpaceX advanced the expected date of a test from mid-2014 to early 2015{{clarify|date=September 2016}}, with the intention of doing so on the [[SpaceX CRS-3|next Space Station cargo resupply flight]] pending regulatory approvals.<ref name="bbc20130930" /><ref name="pa20130930" /> That flight took place on April 18, 2014.<ref name=aw20140428a>{{cite news |last=Norris |first=Guy |title=SpaceX Plans For Multiple Reusable Booster Tests |url=http://aviationweek.com/space/spacex-plans-multiple-reusable-booster-tests |accessdate=May 17, 2014 |newspaper=Aviation Week |date=April 28, 2014 |quote=The April 17 F9R Dev 1 flight, which lasted under 1 min., was the first vertical landing test of a production-representative recoverable Falcon 9 v1.1 first stage, while the April 18 cargo flight to the ISS was the first opportunity for SpaceX to evaluate the design of foldable landing legs and upgraded thrusters that control the stage during its initial descent.}}</ref><ref name="ut20140419">{{cite news |url=http://www.universetoday.com/111377/spacex-makes-strides-towards-1st-stage-falcon-rocket-recovery-during-space-station-launch/ |title=SpaceX Makes Strides Towards 1st Stage Falcon Rocket Recovery during Space Station Launch |work=Universe Today |last=Kremer |first=Ken |date=April 19, 2014 |accessdate=April 19, 2014}}</ref>
Musk stated in May 2013 that the goal of the program is to achieve full and rapid reusability of the first stage by 2015, and to develop full launch vehicle reusability following that as "part of a future design architecture".<ref name="atd20130530">{{cite AV media |url=http://allthingsd.com/20130530/tesla-ceo-and-spacex-founder-elon-musk-the-full-d11-interview-video/ |title=Tesla CEO and SpaceX Founder Elon Musk: The Full D11 Interview (Video) |work=All Things D |last=Gannes |first=Liz |medium=Video interview |section=36:03 |date=May 30, 2013 |accessdate=May 31, 2013 |quote=hopeful that sometime in the next couple of years we'll be able to achieve full and rapid reusability of the first stage—which is about three-quarters of the cost of the rocket—and then with a future design architecture, achieve full reusability. }}</ref>
In February 2014, SpaceX made explicit that the newly defined super-heavy [[ITS launch vehicle|launch vehicle]] for what was then called [[Interplanetary Transport System|Mars Colonial Transporter]] would also make use of the reusable technology.<ref name=nsf20140307>{{cite news |last=Belluscio |first=Alejandro G. |title=SpaceX advances drive for Mars rocket via Raptor power |url=http://www.nasaspaceflight.com/2014/03/spacex-advances-drive-mars-rocket-raptor-power/ |accessdate=April 3, 2014 |newspaper=NASAspaceflight.com |date=March 7, 2014}}</ref>
This was consistent with Musk's strategic statement in 2012 that "The revolutionary breakthrough will come with rockets that are fully and rapidly reusable. We will never conquer [[Mars]] unless we do that. It'll be too expensive. The American colonies would never have been pioneered if the ships that crossed the ocean hadn't been reusable."<ref name=esquire20121115>{{cite news |last=Junod |first=Tom |title=Triumph of His Will |url=http://www.esquire.com/features/americans-2012/elon-musk-interview-1212 |accessdate=April 5, 2014 |newspaper=Esquire |date=November 15, 2012}}</ref>
Also in May 2014, SpaceX publicly announced an extensive test program for a related reusable technology: a propulsively-landed [[space capsule]] called ''[[DragonFly (rocket)|DragonFly]]''. The tests were to be run in Texas at the [[McGregor Rocket Test Facility]] in 2014–2015.<ref name=nbc20140521>{{cite news |last=Boyle |first=Alan |title=Elon Musk's SpaceX Plans DragonFly Landing Tests |url=http://www.nbcnews.com/science/space/elon-musks-spacex-plans-dragonfly-landing-tests-n111386 |accessdate=May 22, 2014 |newspaper=NBC News |date=May 21, 2014}}</ref>
In June 2014, [[Chief operating officer|COO]] [[Gwynne Shotwell]] clarified that all funding for [[new product development|development]] and [[validation and verification|testing]] of the reusable launch system technology development program is private funding from SpaceX, with no contribution by the [[Federal government of the United States|US government]].<ref name=AtlanticCouncil20140604>
{{cite AV media |url=https://www.youtube.com/watch?v=sYocHwhfFDc |title=Discussion with Gwynne Shotwell, President and COO, SpaceX |publisher=Atlantic Council |first=Gwynne |last=Shotwell |time=22:35–26:20 |date=June 4, 2014 |accessdate=June 9, 2014 |quote=''This technology element [reusable launch vehicle technology] all this innovation is being done by SpaceX alone, no one is paying us to do it. The government is very interested in the data we are collecting on this test series. ... This is the kind of thing that entrepreneurial investment and new entrants/innovators can do for an industry: fund their own improvements, both in the quality of their programs and the quality of their hardware, and the speed and cadence of their operations.''}}</ref>
<ref name=sfn20140606>{{cite news |last1=Clark |first1=Stephen |title=SpaceX to balance business realities, rocket innovation |url=http://www.spaceflightnow.com/news/n1406/06spacexmanifest/#.VAoLORaunr5 |accessdate=September 5, 2014 |publisher=Spaceflight Now |date=June 6, 2014 |quote=''SpaceX is using private capital to develop and demonstrate the Falcon 9 rocket's reusability. SpaceX has not disclosed how much the reusable rocket program will cost''}}</ref>
As of 2017 SpaceX had spent over a billion dollars on the development program.<ref>{{cite news |title=SpaceX flies rocket for second time in historic test of cost-cutting technology |url=https://spaceflightnow.com/2017/03/31/spacex-flies-rocket-for-second-time-in-historic-test-of-cost-cutting-technology/ |publisher=Spaceflight Now |first1=Stephen |last1=Clark |date=March 31, 2017 |accessdate=April 22, 2017 |quote=''Musk said SpaceX made the Falcon 9 rocket’s first stage reusable with entirely private funding, investing at least $1 billion in the effort [...]''}}</ref>
For the first time, SpaceX stated in July 2014 that they are "highly confident of being able to land successfully on a [[floating launch platform|floating launch pad]] or back at the launch site and refly the rocket with no required refurbishment."<ref name=sn20140721>
{{cite news |last1=Berger |first1=Brian |title=SpaceX Releases Footage of Falcon 9 First-stage Splashdown |url=http://www.spacenews.com/article/launch-report/41350spacex-releases-footage-of-falcon-9-first-stage-splashdown |accessdate=July 23, 2014 |publisher=SpaceNews |date=July 21, 2014}}</ref>
By late 2014, SpaceX suspended or abandoned the plan to recover and reuse the Falcon 9 second stage;<ref name=mit20141024>{{cite av media |url=https://www.youtube.com/watch?v=y13jbl7ASxY&t=14m20s |title=Elon Musk interview at MIT, October 2014 |date=October 24, 2014 |publisher= |via=YouTube}}</ref> the additional mass of the required heat shield, landing gear, and low-powered landing engines would incur too great a performance penalty.
In September 2016, SpaceX announced that development was underway to extend the reusable flight hardware to second stages, a more challenging engineering problem because the vehicle is travelling at [[Orbital speed#Tangential velocities at altitude|orbital velocity]]. The reusable technology was to have been extended to the 2016 designs of both the [[ITS tanker|tanker]] and [[Interplanetary Spaceship|crewed spaceship]] upper stage variants as well as the [[ITS booster|first stage]] of the [[ITS launch vehicle]] for the [[Interplanetary Transport System]],<ref name=nsf20160927>
{{cite news |last=Bergin |first=Chris |url=https://www.nasaspaceflight.com/2016/09/spacex-reveals-mars-game-changer-colonization-plan/ |title=SpaceX reveals ITS Mars game changer via colonization plan |work=[[NASASpaceFlight.com]] |date=September 27, 2016 |accessdate=October 16, 2016}}</ref><ref name=sn20141024>
{{cite news |last1=Foust |first1=Jeff |title=Next Falcon 9 Launch Could See First-stage Platform Landing |url=http://www.spacenews.com/article/launch-report/42305next-falcon-9-launch-could-see-first-stage-platform-landing |accessdate=October 25, 2014 |work=SpaceNews |date=October 25, 2014}}</ref><ref name=nsf20140307/>
and is considered paramount to the plans Elon Musk is championing to enable the [[Colonization of Mars|settlement of Mars]].<ref name=gq20151212>
{{cite news |last1=Heath |first1=Chris |title=How Elon Musk Plans on Reinventing the World (and Mars) |url=https://www.gq.com/story/elon-musk-mars-spacex-tesla-interview |accessdate=December 12, 2015 |work=GQ |date=December 12, 2015 |quote=''SpaceX exists to further [the vision of humans becoming multi-planetary] on several fronts: to develop the reusable rocket technology that would be needed to ferry large numbers of people, and large amounts of cargo, to Mars; ...''}}</ref><ref name="spacex-itsvideo201609-09:20">
{{cite AV media |people=Elon Musk |date=September 27, 2016 |title=Making Humans a Multiplanetary Species |trans-title= |medium=video |language= |url=https://www.youtube.com/watch?v=H7Uyfqi_TE8 |access-date=October 10, 2016 |format= |time=9:20–10:10 |location=IAC67, Guadalajara, Mexico |publisher=SpaceX |id= |isbn= |oclc= |quote=''So it is a bit tricky. Because we have to figure out how to improve the cost of the trips to Mars by five million percent ... translates to an improvement of approximately 4 1/2 orders of magnitude. These are the key elements that are needed in order to achieve a 4 1/2 order of magnitude improvement. Most of the improvement would come from full reusability—somewhere between 2 and 2 1/2 orders of magnitude—and then the other 2 orders of magnitude would come from refilling in orbit, propellant production on Mars, and choosing the right propellant.'' |ref= }}</ref><ref name=spacex-itspresentation201609>
{{cite web |url=http://www.spacex.com/sites/spacex/files/mars_presentation.pdf |publisher=[[SpaceX]] |title=Making Humans a Multiplanetary Species |date=September 27, 2016 |archive-url=https://web.archive.org/web/20160928040332/http://www.spacex.com/sites/spacex/files/mars_presentation.pdf |archive-date=September 28, 2016 |accessdate=October 16, 2016}}</ref> In 2016, initial test flights of an Interplanetary Transport System vehicle were expected no earlier than 2020.<ref name=nsf20160927/>
In 2017 SpaceX was making test flight progress in [[Iterative and incremental development|incrementally and iteratively]] developing a fairing recovery system.<ref name=verge20170330>
{{cite news |last1=Lopatto |first1=Elizabeth |title=SpaceX even landed the nose cone from its historic used Falcon 9 rocket launch |url=https://www.theverge.com/2017/3/30/15132314/spacex-launch-fairing-landing-falcon-9-thruster-parachutes |accessdate=31 March 2017 |work=[[The Verge]] |date=30 March 2017}}</ref><ref name=sn20170330>
{{cite news |last=Henry |first=Caleb |url=http://spacenews.com/spacex-demonstrates-rocket-reusability-with-ses-10-launch-and-booster-landing/ |title=SpaceX demonstrates reusability |date=March 30, 2017 |work=[[SpaceNews]] |accessdate=13 September 2017 }}</ref>
In July 2017, Musk said "we are quite close to being able to recover the fairing. ... We've got a decent shot of recovering a fairing by the end of the year, and reflight by late this year or early next."<ref name=issR&Dconf20170719-14:15>
{{cite AV media |people=Elon Musk |date=July 19, 2017 |title=Elon Musk, ISS R&D Conference |trans-title= |medium=video |language= |url=https://www.youtube.com/watch?v=BqvBhhTtUm4?t=852 |access-date=September 13, 2017 |format= |time=14:15–15:55 |location=ISS R&D Conference, Washington DC, USA |publisher= |id= |isbn= |oclc= |quote=''I think we are quite close to being able to recover the fairing. ... about a 5 or 6 million dollar piece fo equipment. We've got a decent shot of recovering a fairing by the end of the year, and reflight by late this year or early next. ... Upper stage is about 20 percent of the cost of the mission. So if you get boost stage and fairing we're around 80 percent reusable. ... Think for a lot of missions, we could even bring the second stage back. So were going to try to do that, but our primary focus [for the next couple of years will be crew Dragon].'' }}</ref>
The [[cost]] savings to SpaceX of recovering the fairing is expected to be on the order of {{USD|5 million}}. Together, the booster stage and the fairing make up approximately 80 percent of the cost of a launch.<ref name=issR&Dconf20170719-14:15/>
Despite 2014 plans to suspend development of Falcon 9 second stage reuse,<ref name=mit20141024/>
Musk further commented in July 2017 that a few experimental attempts would be made on particular future flights to bring a Falcon 9 second stage back.<ref name=issR&Dconf20170719-14:15/>
== Technologies ==
Several new technologies needed to be developed and tested to facilitate successful launch and recovery of both [[rocket stage|stages]] of the SpaceX reusable rocket launching system. Following the completion of the third [[SpaceX high-altitude controlled-descent tests|high-altitude controlled-descent test]], and the completion of the third low-altitude flight of the [[F9R Dev|second-generation prototype test vehicle]] (plus eight flights of the first-generation Grasshopper prototype flight test vehicle), SpaceX indicated that they are now able to consistently "reenter from space at hypersonic velocity, restart main engines twice, deploy landing legs and touch down at near zero velocity."<ref name=sn20140721/>
[[File:Falcon 9 1st stage re-entry with grid fins; DSCOVR mission (16849254595).png|thumb|Falcon 9 booster stage re-entry with grid fins, February 2015 following the launch of the [[DSCOVR]] mission]]
The technologies that were developed for this program, some of which are still being refined, include:
* [[Rocket engine restart|restartable]] [[ignition system]] for the first-stage booster.<ref name="musk20130428">{{cite tweet |user=elonmusk |number=328386732934430720 |title=First test of the Falcon 9-R (reusable) ignition system |date=April 28, 2013}}</ref><!-- the Falcon 9 second stage, Merlin 1C vacuum engine has had restartable ignition for some time. --> Restarts are required at both supersonic velocities in the upper atmosphere—in order to decelerate the high velocity away from the launch pad and put the booster on a descent trajectory back toward the launch pad—and at high [[transonic]] velocities in the lower atmosphere—in order to slow the terminal descent and to perform a soft landing.<ref name="pa20150110">{{cite video |people=Gwynne Shotwell |url=https://www.youtube.com/watch?v=XtNgWK4mm0M |title=Singapore Satellite Industry Forum 2013 - Opening Keynote |accessdate=April 9, 2016 |date=June 17, 2013 |time=16:15–17:05 |quote=The Dragon capsule has a shape that is stable on reentry from orbit, whereas rocket states traditionally are not stable on reentry, so there is a lot of software involved, a lot of guidance navigation and control involved, and a lot of thermal protection required; so we have to make advances in all those areas. We also have to restart the engines supersonically.}}</ref>
* new [[attitude control]] technology{{mdash}}for the booster stage and second stage{{mdash}}to bring the descending [[rocket body]] through the atmosphere in a manner conducive both to non-destructive return and [[Aerodynamic control surfaces|sufficient aerodynamic control]] such that the terminal phase of the [[VTVL|landing]] is possible.<ref name=pa20140114vid>
{{cite video |people=Gwynne Shotwell |url=https://www.youtube.com/watch?v=XtNgWK4mm0M |title=Singapore Satellite Industry Forum 2013 - Opening Keynote |accessdate=April 9, 2016 |date=June 17, 2013}}</ref> This includes sufficient roll [[Control system|control authority]] to keep the rocket from spinning excessively as occurred on the [[Falcon 9 Flight 6#Post-mission launch vehicle testing|first high-altitude flight test]] in September 2013, where the roll rate exceeded the capabilities of the booster [[attitude control system]] (ACS) and the fuel in the tanks "centrifuged" to the side of the tank shutting down the single engine involved in the low-altitude deceleration maneuver.<ref name="pa20130930" /><ref name=tss20140321b>{{cite AV media|people=Gwynne Shotwell |date=March 21, 2014 |title=Broadcast 2212: Special Edition, interview with Gwynne Shotwell |medium=audio file |url=http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 |accessdate=March 22, 2014 |archiveurl=https://web.archive.org/web/20140322013556/http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 |archivedate=March 22, 2014 |format=mp3 |time=51;50–52;55 |publisher=The Space Show |id=2212 |quote= |deadurl=yes |df= }}</ref> The technology needs to handle the transition from the vacuum of space at [[hypersonic]] conditions, decelerating to [[supersonic]] velocities and passing through [[transonic]] [[Buffet (turbulence)|buffet]], before relighting one of the main-stage engines at [[terminal velocity]].<ref name=pm20130930/>
* hypersonic [[grid fin]]s were added to the booster test vehicle design beginning on the [[Falcon 9 Flight 14|fifth ocean controlled-descent test flight]] in 2014 in order to enable precision landing. Arranged in an "X" configuration, the grid fins control the descending rocket's [[lift vector]] once the vehicle has returned to the atmosphere to enable a much more precise [[Landing ellipse|landing location]].<ref name=sx20141216>
{{cite web |title=X MARKS THE SPOT: FALCON 9 ATTEMPTS OCEAN PLATFORM LANDING |url=http://www.spacex.com/news/2014/12/16/x-marks-spot-falcon-9-attempts-ocean-platform-landing |publisher=SpaceX |accessdate=December 17, 2014 |date=December 16, 2014 |quote=A key upgrade to enable precision targeting of the Falcon 9 all the way to touchdown is the addition of four hypersonic grid fins placed in an X-wing configuration around the vehicle, stowed on ascent and deployed on reentry to control the stage’s lift vector. Each fin moves independently for roll, pitch and yaw, and combined with the engine gimbaling, will allow for precision landing – first on the autonomous spaceport drone ship, and eventually on land.}}<!-- quotation added as SpaceX often removes these sorts of news source pages after some months --></ref><ref name=blackmore2016/> Iteration on the design continued into 2017. Larger and more robust grid fins, made from forged [[titanium]] and left unpainted, were first tested in June 2017, and will be used on all reusable Block 5 Falcon 9 first stages starting in late 2017.<ref>[https://www.nasaspaceflight.com/2017/06/spacex-falcon-9-iridium-next-2-launch/ https://www.nasaspaceflight.com/2017/06/spacex-falcon-9-iridium-next-2-launch/]</ref>
[[File:Falcon 9 with CRS-3 Dragon in SLC-40 hangar (16855338881).jpg|thumb|left|Falcon 9 v1.1 with landing legs attached, in stowed position as the rocket is prepared for launch in its hangar]]
* [[Rocket engine throttling|throttleable rocket engine]] technology is required to reduce engine thrust because the full thrust of even a single [[Merlin 1D]] engine exceeds the weight of the nearly empty booster core.<ref name=fg20130321>{{cite news |last=Rosenberg |first=Zach |title=SpaceX Merlin 1D qualified for flight |url=http://www.flightglobal.com/news/articles/spacex-merlin-1d-qualified-for-flight-383738/ |accessdate=March 18, 2014 |newspaper=Flightglobal |date=March 21, 2013}}</ref><ref name=slr20140312>{{cite web |title=SpaceX Falcon 9 v1.1 Data Sheet |url=http://www.spacelaunchreport.com/falcon9v1-1.html |publisher=Space Launch Report |accessdate=March 18, 2014 |date=March 12, 2014}}</ref><ref name=blackmore2016/>
* [[attitude control|terminal guidance]] and landing capability,<ref name="nsj20130309">{{cite news |url=http://www.newspacejournal.com/2013/03/09/more-on-grasshoppers-johnny-cash-hover-slam-test/ |title=More on Grasshopper's "Johnny Cash hover slam" test |work=NewSpace Journal |last=Foust |first=Jeff |date=March 9, 2013 |accessdate=May 2, 2013}}</ref> including a [[Guidance, navigation and control|vehicle control system]] and a control system [[Real-time computing|software algorithm]] to be able to land a rocket with the thrust-to-weight ratio of the vehicle greater than one,<ref name="nbc20130309">{{cite news |url=http://cosmiclog.nbcnews.com/_news/2013/03/09/17251376-spacexs-elon-musk-shows-off-grasshopper-test-rockets-latest-hop?lite |title=SpaceX's Elon Musk shows off Grasshopper test rocket's latest hop |work=NBC News |last=Boyle |first=Alan |date=May 2, 2013 |accessdate=March 9, 2013}}</ref> with [[Closed-loop control|closed-loop]] [[thrust-vector|thrust vector]] and [[throttleable|throttle control]]<ref>{{cite news |url=http://www.dailykos.com/story/2013/03/09/1192883/-Woo-hoo-Awesome-SpaceX-Grasshopper-Hover-Slam-Launch-Doubles-Previous-Height-w-Video |title=Woo-hoo! Awesome SpaceX Grasshopper "Hover-Slam" Rocket Launch Doubles Previous Height |work=Daily Kos |date=March 9, 2013}}</ref><ref name=blackmore2016/>
* [[GN&C|navigation]] sensor suite for precision landing<ref name=pa20140114vid/><ref name="sx20130705">{{cite video |url=https://www.youtube.com/watch?v=eGimzB5QM1M |title=Grasshopper 325m Test {{!}} Single Camera (Hexacopter) |work=YouTube.com |publisher=SpaceX |date=June 14, 2013 |accessdate=July 6, 2013 }}</ref><ref name=blackmore2016/>
[[File:Autonomous Spaceport Drone Ship - Just Read the Instructions (16450469297).png|thumb|Autonomous Spaceport Drone Ship, in port in January 2015.]]
* a large [[floating landing platform]] in order to test pinpoint landings prior to receiving permission from the [[Federal government of the United States|US government]] to bring returning rocket stages into US [[airspace]] over land. In the event, SpaceX built the ''[[autonomous spaceport drone ship]]'' in 2014,<ref name=nsf20141124/> and conducted an initial flight test and landing attempt in January 2015.<ref name=nsf20141217>
{{cite news |last1=Bergin |first1=Chris |title=SpaceX confirms CRS-5 launch slip to January 6 |url=http://www.nasaspaceflight.com/2014/12/spacex-static-fire-falcon-9-crs-5/ |accessdate=December 24, 2014 |work=NASASpaceFlight.com |date=December 17, 2014}}</ref>
* large-surface-area [[thermal protection system]] to absorb the heat load of deceleration of the second stage from [[Orbital speed|orbital velocity]] to terminal velocity<ref name=pa20140114vid/><ref name=tsr20140324>{{cite journal |last=Foust |first=Jeff |title=Reusability and other issues facing the launch industry |journal=The Space Review |date=March 24, 2014 |url=http://www.thespacereview.com/article/2476/1 |accessdate=April 1, 2014}}</ref><ref name=blackmore2016/>
* lightweight, deployable [[Launch vehicle landing gear|landing gear]] for the booster stage.<ref name="satspot20110926" /><ref name=blackmore2016>
{{cite journal |title=Autonomous Precision Landing of Space Rockets |journal=The Bridge, National Academy of Engineering |date=Winter 2016 |last=Blackmore |first=Lars |volume=46 |issue=4 |pages=15–20 |issn=0737-6278 |url=http://web.mit.edu/larsb/www/nae_bridge_2016.pdf |accessdate=January 15, 2017}}</ref> In May 2013, the design was shown to be a nested, telescoping piston on an A-frame. The total span of the four [[carbon fiber]]/[[aluminum]] extensible landing legs<ref name="sxn20130729legs">{{cite web |url=http://www.spacex.com/news/2013/03/26/landing-leg |title=Landing Legs |work=SpaceX.com |date=July 29, 2013 |accessdate=December 4, 2013 |quote=The Falcon 9 first stage carries landing legs which will deploy after stage separation and allow for the rocket’s soft return to Earth. The four legs are made of state-of-the-art carbon fiber with aluminum honeycomb. Placed symmetrically around the base of the rocket, they stow along the side of the vehicle during liftoff and later extend outward and down for landing.}}</ref><ref name="sxn20130802fh_legs">{{cite web |url=http://www.spacex.com/news/2013/04/12/falcon-heavy-landing-legs |title=Falcon Heavy Landing Legs |work=SpaceX.com |date=April 12, 2013 |accessdate=December 4, 2013 |quote=The Falcon Heavy first stage center core and boosters each carry landing legs, which will land each core safely on Earth after takeoff. After the side boosters separate, the center engine in each will burn to control the booster’s trajectory safely away from the rocket. The legs will then deploy as the boosters turn back to Earth, landing each softly on the ground. The center core will continue to fire until stage separation, after which its legs will deploy and land it back on Earth as well. The landing legs are made of state-of-the-art carbon fiber with aluminum honeycomb. The four legs stow along the sides of each core during liftoff and later extend outward and down for landing.}}</ref> is approximately {{convert|60|ft|m|order=flip|sp=us}}, and weigh less than {{convert|2100|kg}}. Deployment system uses high-pressure [[Helium]] as the [[working fluid]].<ref name="musk20130502">{{cite news |url=http://www.newspacewatch.com/articles/spacex-shows-a-leg-for-the-quotf-ninerquot.html |title=SpaceX shows a leg for the "F-niner" |work=NewSpace Watch |last=Lindsey |first=Clark |date=May 2, 2013 |accessdate=May 2, 2013 <!-- REMOVED https://archive.is/ archive link, as a wikibot reports that is is on some sort of "local blacklist". See page history on 2016-04-05 for more info |archiveurl=https://archive.is/20130630001715/http://www.newspacewatch.com/articles/spacex-shows-a-leg-for-the-quotf-ninerquot.html |archivedate=June 30, 2013 --> |quote=F9R (pronounced F-niner) shows a little leg. Design is a nested, telescoping piston w A frame... High pressure helium. Needs to be ultra light. |subscription=yes}}</ref><ref name=nsf20140228>{{cite news |last=Bergin |first=Chris |title=SpaceX outlines CRS-3 landing legs plan toward first stage recovery ambitions |url=http://www.nasaspaceflight.com/2014/02/spacex-crs-3-landing-legs-plan-first-stage-recovery-ambitions/ |accessdate=May 10, 2014 |newspaper=NASAspaceflight.com |date=February 28, 2014}}</ref> With [[Falcon 9 first-stage landing tests#Flight 25|Flight 25]] it was announced that each landing leg contained a "crush core", to absorb the impact of landing for particularly hard landings.<ref name="space.com">{{cite news |last1=Wall |first1=Mike |title=SpaceX's Leaning Rocket Tower Comes Ashore (Photos) |url=http://www.space.com/33102-spacex-leaning-rocket-comes-ashore-photos.html |accessdate=June 7, 2016 |date=June 7, 2016}}</ref><ref>{{Cite web |url=https://twitter.com/elonmusk/status/736328917317910528?lang=en |title=Elon Musk on Twitter |website=Twitter |access-date=June 8, 2016 |quote=The crush core in the Falcon legs is reusable after soft landings, but needs to be replaced after hard.}}</ref>
== Economics of rocket reuse ==
In order to make the Falcon 9 reusable and return to the launch site, extra [[rocket propellant|propellant]] and [[landing gear]] must be carried on the first stage, requiring around a 30 percent reduction of the maximum payload to orbit in comparison with the expendable Falcon 9.<ref name="bbc20130930" /> [[Reusable launch system|Reflight]] of a previously used stage on a subsequent flight is dependent on the condition of the landed stage, and is a technique that has seen little use outside of the [[Space Shuttle]]'s reusable [[Space Shuttle Solid Rocket Booster|solid rocket boosters]]. In September 2013, SpaceX said that if all aspects of the test program were successful and if a customer is interested, the first reflight of a Falcon 9 booster stage could happen as early as late 2014.<ref name="bbc20130930" /><!-- should the historical statement re 2013 no longer belong in this section, it should probably move to the History subsection, and not just be deleted completely from this "good article." -->
In December 2015, following the recovery of the [[Falcon 9 Flight 20|first stage from December 22 launch]], SpaceX projected that the first reflight of a recovered booster would likely occur in 2016, but that their plan was to not refly December 22 recovered stage for that purpose.<ref name=bi20151225>
{{cite news |url=http://www.cbsnews.com/news/experts-applaud-spacex-landing-cautious-about-outlook/ |title=Elon Musk's SpaceX already knows what it's going to do with the history-making rocket — but it's not what you think |author=Jessica Orwig |work=Business Insider |date=December 25, 2015 |accessdate=December 25, 2015}}</ref>
Musk projects that the reflight step of the program will be "straightforward," because of the multiple full duration firings of the engines that have been done on the ground, and the multiple engine restarts that have already been demonstrated, with no significant degradation seen.<ref name=presserTranscript20151222>
{{cite web |title=Postlanding teleconference with Elon Musk |url=http://shitelonsays.com/transcript/postlanding-teleconference-with-elon-musk-2015-12-22# |date=December 22, 2015 |accessdate=December 25, 2015}}</ref>
Several industry analysts continue to see potential problems that could prevent economic reuse because costs to refurbish and relaunch the stage are not yet demonstrated. Moreover, the economic case for reuse will be highly dependent on launching frequently, and that is simply unknown as of 2015.<ref name=cbs20151222>
{{cite news |title=Experts applaud SpaceX rocket landing, potential savings |author=Bill Harwood |url=http://www.cbsnews.com/news/experts-applaud-spacex-landing-cautious-about-outlook/ |work=CBS News |date=December 22, 2015 |accessdate=December 25, 2015}}</ref>
If SpaceX is successful in developing the reusable technology, it is expected to significantly reduce the cost of access to space, and change the increasingly competitive market in space launch services.<ref name="bbc20130930">{{cite news |url=http://www.bbc.co.uk/news/science-environment-24331860 |title=Recycled rockets: SpaceX calls time on expendable launch vehicles |work=BBC News |last=Amos |first=Jonathan |date=September 30, 2013 |accessdate=October 2, 2013}}</ref><ref name=tsr20140310>{{cite journal |last=Boozer |first=R.D. |title=Rocket reusability: a driver of economic growth |journal=The Space Review |date=March 10, 2014 |url=http://www.thespacereview.com/article/2466/1 |accessdate=March 25, 2014}}</ref> Michael Belfiore wrote in ''[[Foreign Policy (magazine)|Foreign Policy]]'' in 2013 that, at a published cost of {{USD|56.5 million}} per launch to [[low Earth orbit]], "Falcon 9 rockets are already the cheapest in the industry. Reusable Falcon 9s could drop the price by an [[order of magnitude]], sparking more space-based enterprise, which in turn would drop the cost of access to space still further through economies of scale."<ref name=fp20131209>{{cite news |url=https://foreignpolicy.com/articles/2013/12/02/the_rocketeer_elon_musk |title=The Rocketeer |work=[[Foreign Policy (magazine)|Foreign Policy]] |last=Belfiore |first=Michael |date=December 9, 2013 |accessdate=December 11, 2013}}</ref> Even for military launches, which have a number of contractual requirements for additional launch services to be provided, SpaceX's price is under {{USD|100 million}}.<ref name=mit20140422>
{{cite news |last=Belfiore |first=Michael |title=SpaceX Brings a Booster Safely Back to Earth |url=http://www.technologyreview.com/news/526806/spacex-brings-a-booster-safely-back-to-earth/ |accessdate=April 25, 2014 |newspaper=MIT Technology Review |date=April 22, 2014}}</ref><ref name=bi20141125>
{{cite news |last1=Orwig |first1=Jessica |title=Elon Musk Just Unveiled A Game-Changing Ocean Landing Pad For His Reusable Rockets |url=http://www.businessinsider.com/elon-musk-rockets-that-land-at-sea-2014-11 |accessdate=December 11, 2014 |work=Business Insider |date=November 25, 2014 |quote=''The first successful "soft landing" of a Falcon 9 rocket happened in April of this year''}}</ref>
[[File:Falcon 9 First Stage Reusability Graphic.jpg|thumb|upright=2|Depiction of Falcon 9 landing trajectory for some of the floating-platform recovery tests]]<!-- not all of the controlled-descent tests had three post-separation burns; e.g., some of the early ones only had two burns, and skipped the boostback burn. -->
Space industry analyst Ajay Kothari has noted that SpaceX reusable technology could do for [[space transport]] "what jet engines did for air transportation sixty years ago when people never imagined that more than 500 million passengers would travel by airplanes every year and that the cost could be reduced to the level it is—all because of passenger volume and reliable reusability."<ref name=tsr20140414>
{{cite news |last=Kothari |first=Ajay P. |title=Robust and reusable? |url=http://www.thespacereview.com/article/2490/1 |accessdate=April 14, 2014 |newspaper=The Space Review |date=April 14, 2014}}</ref>
SpaceX said in January 2014 that if they are successful in developing the reusable technology, launch prices of around {{USD|5 to 7 million}} for a reusable Falcon 9 were possible,<ref name=ps20140114>{{cite news |last=Messier |first=Doug |title=Shotwell: Reusable Falcon 9 Would Cost $5 to $7 Million Per Launch |url=http://www.parabolicarc.com/2014/01/14/shotwell/ |accessdate=January 15, 2014 |newspaper=Parabolic Arc |date=January 14, 2014}}</ref>
and following the successful first stage recovery in December 2015, Musk said that "the potential cost reduction over the long term is probably in excess of a factor of 100."<ref name=cbs20151222/>
{{asof|2014|03}} launch service providers who [[Market competition|compete]] with SpaceX were not planning to develop similar technology or offer competing reusable launcher options. Neither [[International Launch Services|ILS]], which markets launches of the Russian [[Proton rocket]]; [[Arianespace]]; nor [[SeaLaunch]] were planning on developing and marketing reusable launch vehicle services. SpaceX was the only competitor that projected a sufficiently [[Price elasticity of demand|elastic]] market on the demand side to justify the costly development of reusable rocket technology and the expenditure of [[Capital (economics)|private capital]] to develop options for that theoretical market opportunity.<ref name=tsr20140324/>
{{As of|2014}}, the Falcon 9 v1.1 rocket was designed with about 30 percent more capacity than its official payload specifications; the additional performance was reserved for SpaceX to perform [[Falcon 9 first-stage landing tests|first-stage re-entry and landing tests]] towards reusability while still achieving the specified orbital payload delivery for customers.<ref name=tss20140321a>{{cite AV media|people=Gwynne Shotwell |date=March 21, 2014 |title=Broadcast 2212: Special Edition, interview with Gwynne Shotwell |medium=audio file |url=http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 |accessdate=March 22, 2014 |archiveurl=https://web.archive.org/web/20140322013556/http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 |archivedate=March 22, 2014 |format=mp3 |time=08:15–11:20 |publisher=The Space Show |id=2212 |quote=[Falcon 9 v1.1] vehicle has thirty percent more performance than what we put on the web and that extra performance is reserved for us to do our reusability and recoverability [tests] ... current vehicle is sized for reuse. |deadurl=yes |df= }}</ref>
In order to achieve the full economic benefit of the reusable technology, it is necessary that the reuse be both rapid and complete—without the long and costly refurbishment period or partially reusable design that plagued earlier attempts at reusable launch vehicles. SpaceX has been explicit that the "huge potential to open up space flight"<ref name=nsf20140422>{{cite news |last=Bergin |first=Chris |title=Rockets that return home – SpaceX pushing the boundaries |url=http://www.nasaspaceflight.com/2014/04/rockets-return-home-spacex-pushing-boundaries/ |accessdate=April 23, 2014 |newspaper=NASAspaceflight.com |date=April 22, 2014}}</ref> is dependent on achieving both complete and rapid reusability.<ref name=aw20140428a/><ref name=mit20140422/>
CEO Musk stated in 2014 that success with the technology development effort could reduce "the cost of spaceflight by a factor of 100"<ref name=sdc20140907>
{{cite news |last1=Wall |first1=Mike |title=Dazzling SpaceX Nighttime Launch Sends AsiaSat 6 Satellite Into Orbit |url=http://www.space.com/27052-spacex-launches-asiasat6-satellite.html |accessdate=September 7, 2014 |publisher=SPACE.com |date=September 7, 2014 |quote=''SpaceX's work with the F9R is part of an effort to develop fully and rapidly reusable launch systems, a key priority for the company. Such technology could slash the cost of spaceflight by a factor of 100.''}}</ref> because the cost of the propellant/oxidizer on the Falcon 9 is only 0.3 percent of the total cost of the vehicle.<ref>{{cite web |url=http://www.space.com/21386-spacex-reusable-rockets-cost.html |title=SpaceX Chief Says Reusable First Stage Will Slash Launch Costs |author=Peter B. de Selding, Space News |work=Space.com}}</ref>
Separate from the [[Space launch market competition|market competition]] brought about by SpaceX lower launch prices and the potential future of even more radically lower launch prices if the technology can be completed successfully, ''[[Aviation Week]]'' said in 2014 that "SpaceX reusable launch work is an [[Research and development|R&D]] model"—"The audacity of the concept and speed of the program’s progress make it an exemplar. ... [the] breakneck pace of development has been almost [[Apollo program|Apollo]]-like in its execution... [even while] success is far from guaranteed."<ref name=aw20140428b>{{cite news |title=SpaceX’s Plan Shows Aggressive Investment In R&D |url=http://m.aviationweek.com/space/editorial-spacex-s-plan-shows-aggressive-investment-rd |accessdate=May 17, 2014 |newspaper=Aviation Week |date=April 28, 2014}}</ref>
On March 9, 2016, SpaceX President Gwynne Shotwell gave a more realistic appraisal of the potential savings of a reused launch now that attempts to reuse the second stage had been abandoned due to cost and weight issues. She said at {{USD|1 million}} cost of refueling and {{USD|3 million}} cost of refurbishing a used first stage could potentially allow a launch to be priced as low as {{USD|40 million}}, a 30% saving. SpaceX biggest customer SES said it wants to be the first to ride a reused vehicle, however it wants a launch price of {{USD|30 million}} or a 50% saving to offset the risk of pioneering the process.<ref>{{cite web |url=http://spacenews.com/spacex-says-reusable-stage-could-cut-prices-by-30-plans-first-falcon-heavy-in-november/ |title=SpaceX says reusable stage could cut prices 30 percent, plans November Falcon Heavy debut |work=SpaceNews.com |date=2016-03-10 |accessdate=2017-05-27 }}</ref>
According to Elon Musk, almost every piece of the Falcon should be reused over 100 times. Heat shields and a few other items should be reused over 10 times before replacement.<ref>https://twitter.com/elonmusk/status/726216836069515264</ref> In March 2017, SpaceX announced progress in their experiments to recover, and eventually reuse, the 6-million dollar [[payload fairing]]. On the [[SES-10]] mission, one of the fairing halves performed a controlled atmospheric reentry and [[splashdown]] using thrusters and a steerable parachute; fairings are eventually slated to land on a floating "bouncy castle" structure.<ref name=floridatoday_26216836069515264>{{cite news|url= http://www.floridatoday.com/story/tech/science/space/2017/03/31/things-we-learned-spacex-elon-musk-falcon9-reusability-kennedy-space-center-florida-ses10/99869966/ |title= Things we learned after SpaceX's historic Falcon 9 relaunch and landing |website= [[Florida Today]] |first= Emre |last= Kelly |date= 2017-03-31 |accessdate= 2017-04-01}}</ref>
SpaceX began re-flight of previously-launched booster stages in 2017. The first re-flight was accomplished in March 2017, nearly a year after the booster's [[maiden flight]]; the second was in June 2017, only five months after its maiden flight. Both were successful, and both [[insurer]]s and launch service customers are readily supporting the newly emerging market in launch services provided by multiple-use boosters.<ref name=sir-20170626>{{cite web |url=https://www.spaceintelreport.com/spacex-cuts-flight-refurbish-reflight-time-falcon-9-first-stage/ |title=SpaceX cuts flight-to-reflight time for Falcon 9 first stage |work=Space Intel Report |first=Peter B. |last=de Selding |date=June 26, 2017 |access-date=June 27, 2017}}</ref>
== Technical feasibility ==
Prior to the reusability program's success in December 2015, the [[Return To Launch Site|return]] of an orbital launch system booster rocket had never been accomplished, and many questioned both technical and economic feasibility. And even after this success, the ''rapid'' reuse of a rocket has not been attempted. Developing a reusable rocket is extremely challenging due to the small percentage of a rocket's mass that can make it to orbit.<ref name="sdc20110930"/><ref name=am201404>
{{cite news |last1=Clash |first1=Jim |title=Elon Musk Interview |url=http://www.askmen.com/entertainment/right-stuff/elon-musk-interview-2.html |accessdate=September 27, 2014 |work=AskMen |date=April 2014 |quote=''Expendable rockets, which many smart people have worked on in the past, get maybe 2% of liftoff mass to orbit -- really not a lot. Then, when they’ve tried reusability, it’s resulted in negative payload, a 0 to 2% minus payload [laughs]. The trick is to figure out how to create a rocket that, if it were expendable, is so efficient in all of its systems that it would put 3% to 4% of its mass into orbit. On the other side, you have to be equally clever with the reusability elements such that the reusability penalty is no more than 2%, which would leave you with a net ideally of still 2% of usable load to orbit in a reusable scenario, if that makes sense. You have to pry those two things apart: Push up payload to orbit, push down the mass penalty for reusability -- and have enough left over to still do useful work.''}}</ref> Typically, a rocket's payload is only about 3% of the mass of the rocket which is also roughly the amount of mass in fuel that is required for the vehicle's re-entry.<ref name="youtube20110929">{{cite web |url=https://www.youtube.com/watch?v=xrVD3tcVWTY |title=National Press Club: The Future of Human Spaceflight |date=September 29, 2011}}</ref>
Elon Musk said at the beginning of the program that he believed the return, vertical landing and recovery was possible because the SpaceX manufacturing methodologies result in a rocket efficiency exceeding the typical 3% margin. A SpaceX rocket operating in the reusable configuration has approximately 30% less payload lift capacity than the same rocket in an [[expendable rocket|expendable]] configuration.<ref name=pm20130930/>
Although the [[reusable launch system]] technology was developed and initially used for the first stages of the Falcon family of rockets<ref name=sn20141024/> it is particularly well suited to the Falcon Heavy where the two [[Modular rocket|outer cores]] [[separation event|separate]] from the rocket earlier in the flight, and are therefore moving more slowly at stage separation. For example, on [[Falcon 9 Flight 20|Falcon 9 flight 20]], the speed at separation was close to 6000 km/h<ref>{{cite video |url=https://www.youtube.com/watch?v=3G8GJQumBFs |title=ORBCOMM-2 Full Launch Webcast |time=25:25 |publisher=SpaceX |accessdate=April 9, 2016 |date=December 21, 2015}}</ref> and this allowed a return to near the launch site. On [[Falcon 9 Flight 22|flight 22]], going to a more-energetic [[Geostationary transfer orbit|GTO]] orbit, the higher velocity at separation was between 8000 and 9000 km/h. At these faster speeds it is not possible to return the booster to near the launch site for a landing; if a landing is attempted it needs to be hundreds of kilometers downrange on an [[Autonomous spaceport drone ship|autonomous droneship]].
== Test program ==
In 2013 SpaceX was testing reusable technologies both for its [[Booster (rocketry)|first-stage booster]] launch vehicle designs (with three test vehicles : [[Grasshopper (rocket)|Grasshopper]], [[F9R Dev1]], and [[F9R Dev2]]) — and for its new reusable [[Dragon V2]] [[space capsule]] (with a low-altitude test vehicle called [[DragonFly (rocket)|DragonFly]]).
SpaceX has publicly disclosed a multi-element, incremental test program for booster stages that includes four aspects:
* low-altitude (less than {{convert|760|m|ft|-2|disp=x|/|abbr=on}}<ref name="faa20110922" /><ref name=wt20130508>{{cite news |last=Abbott |first=Joseph |title=SpaceX's Grasshopper leaping to NM spaceport |url=http://www.wacotrib.com/news/business/spacex-s-grasshopper-leaping-to-nm-spaceport/article_de2126cd-d6ec-563b-b84b-532641e709e3.html |accessdate=October 25, 2013 |newspaper=Waco Tribune |date=May 8, 2013}}</ref>), low-velocity testing of its single-engine [[Grasshopper (rocket)|Grasshopper]] technology-demonstrator at its Texas test site
* low-altitude (less than {{convert|3000|m|ft|-2|disp=x|/|abbr=on}}), low-velocity testing of a much larger, second-generation, three-engine test vehicle called [[F9R Dev1]]. The second generation vehicle includes extensible landing legs and will be tested at the Texas test site<ref name=tsr20140505>{{cite news |last=Foust |first=Jeff |title=Following up: reusability, B612, satellite servicing |url=http://www.thespacereview.com/article/2505/1 |accessdate=May 6, 2014 |newspaper=The Space Review |date=May 5, 2014}}</ref>
* high-altitude, mid-velocity testing was planned but cancelled in favor of [[Falcon 9 first-stage landing tests|post-mission re-entry tests of first-stage boosters]]. It would have used F9R Dev2 at a SpaceX leased facility at [[Spaceport America]] in [[New Mexico]].
* high-altitude ({{convert|91|km|ft|-5|disp=x|/|abbr=on}}<ref name="nbf20130323">{{cite news |url=http://nextbigfuture.com/2013/03/spacex-may-try-to-land-recover-first.html |title={{Sic |hide=y|Spacex}} May try to "land / recover" the first stage of it next Falcon 9 v1.1 launch this summer |work=Next Big Future |first=Brian |last=Wang |date=March 23, 2013 |accessdate=April 6, 2013}}</ref>), very-high-velocity (approximately {{nowrap|2.0 km/s}}; {{nowrap|6,500 km/h; 4,100 mph; Mach 6}}<ref name="pm20120207" />) [[ballistic reentry]], [[SpaceX high-altitude controlled-descent tests|controlled-deceleration and controlled-descent tests]] of post-mission (spent) Falcon 9 booster stages following a subset of Falcon 9 launches that began in 2013.
Eight low-altitude booster flight tests were made by Grasshopper in 2012 and 2013.
The first [[booster rocket|booster return]] controlled-descent test from high-altitude was made in September 2013, with a second test in April,<ref name="bbc20130930" /><ref name="ut20140419" /><ref name=dn20140224/>
a [[Falcon 9 Flight 10|third test flight]] in July<ref name=nsf20140728>
{{cite news |last1=Bergin |first1=Chris |title=SpaceX Roadmap building on its rocket business revolution |url=http://www.nasaspaceflight.com/2014/07/spacex-roadmap-rocket-business-revolution/ |accessdate=July 28, 2014 |publisher=NASAspaceflight |date=July 28, 2014 |quote=''At this point, we are highly confident of being able to land successfully on a floating launch pad or back at the launch site and refly the rocket with no required refurbishment''}}</ref>
and a [[Falcon 9 Flight 13|fourth test]] in September 2014. All four test flights to date were intended to be over-water, simulated landings.<ref name=sn20140721/>
Five low-altitude booster flight tests of F9R Dev1 were flown during April–August 2014, before the vehicle self-destructed for safety reasons on the fifth flight.<ref name=wt20140417>
{{cite news |last=Abbott |first=Joseph |title=Grasshopper's successor flies at SpaceX's McGregor site |url=http://www.wacotrib.com/blogs/joe_science/grasshopper-s-successor-flies-at-spacex-s-mcgregor-site/article_66310240-c67f-11e3-bf29-001a4bcf887a.html |accessdate=April 18, 2014 |newspaper=Waco Tribune |date=April 17, 2014}}</ref><ref name=nsj20140823>
{{cite news |last1=Foust |first1=Jeff |title=Falcon 9 test vehicle destroyed in accident |url=http://www.newspacejournal.com/2014/08/23/falcon-9-test-vehicle-destroyed-in-accident/ |accessdate=August 23, 2014 |publisher=NewSpace Journal |date=August 23, 2014}}</ref>
=== Flight test vehicles ===
[[File:SpaceX Grasshopper rocket midflight.png|thumb|Grasshopper rocket performing a 325 meter flight followed by a soft propulsive landing in an attempt to develop technologies for a reusable launch vehicle.]]
SpaceX used a set of experimental technology-demonstrator, [[suborbital]] [[Reusable launch system|reusable launch vehicles]] (RLV) to begin [[flight testing]] their reusable rocket technologies in 2012. Two versions of the prototype reusable test rockets were built—the 106-foot tall ''Grasshopper'' (formerly designated as ''Grasshopper v1.0'') and the 160-foot tall ''Falcon 9 Reusable Development Vehicle'', or ''F9R Dev1''—formerly known as ''Grasshopper v1.1''<ref name=nsf20140422/>—as well as a [[space capsule|capsule prototype]] for testing propulsive landings of the [[Dragon 2|Dragon]] crew and cargo capsule for the Falcon 9—''DragonFly''.<ref name=nsf20140422/>
Grasshopper was built in 2011–2012 for low-altitude, low-velocity hover testing that began in September 2012 and concluded in October 2013 after eight test flights.<ref name="faa20110922" /><ref name="satspot20110926" /><ref name=nsf20140422/>
The second prototype vehicle design, F9R Dev1, was built on the much larger [[Falcon 9 v1.1]] booster stage was used to further extend the low-altitude flight testing [[flight envelope|envelope]] on a vehicle that better matched the actual flight hardware, and made five test flights in 2014.<ref name=nsf20140422/><ref name="msnbc20110927">{{cite news |url=http://www.nbcnews.com/id/44692930/ |title=A rocket that lifts off—and lands—on launch pad |work=NBC News |last=Klotz |first=Irene |date=September 27, 2011 |accessdate=November 23, 2011}}</ref><ref name="nsw20121002" />
The low-altitude, low-speed flights of the test vehicle rockets and capsule were conducted at the [[SpaceX Rocket Development and Test Facility|SpaceX Rocket Test Facility]] in [[McGregor, Texas]]<ref name="faa20110922" /><ref name="satspot20110926" /><ref name=nsf20140422/>
==== Grasshopper ====
{{main|Grasshopper (rocket)}}
Grasshopper, the company's first [[VTVL]] test vehicle, consisted of a [[Falcon 9 v1.0]] first-stage tank, a single [[Merlin 1D|Merlin-1D]] engine, and four permanently attached steel landing legs. It stood {{convert|106|ft}} tall.<ref name="satspot20110926">{{cite news |url=http://satellite.tmcnet.com/topics/satellite/articles/222324-spacex-plans-test-reusable-suborbital-vtvl-rocket-texas.htm |title=SpaceX Plans to Test Reusable Suborbital VTVL Rocket in Texas |newspaper=Satellite Spotlight |last=Mohney |first=Doug |date=September 26, 2011 |accessdate=November 21, 2013}}</ref> SpaceX built a {{Convert|0.5|acre|ha|adj=on}} concrete launch facility at its Rocket Development and Test Facility in [[McGregor, Texas]] to support the Grasshopper flight test program.<ref name="sfn20120709">{{cite news |url=http://www.spaceflightnow.com/news/n1207/10grasshopper/ |title=Reusable rocket prototype almost ready for first liftoff |newspaper=Spaceflight Now |first=Stephen |last=Clark |date=July 9, 2012 |accessdate=July 13, 2012 |quote=SpaceX has constructed a half-acre concrete launch facility in McGregor, and the Grasshopper rocket is already standing on the pad, outfitted with four insect-like silver landing legs.}}</ref>
Grasshopper was also known as Grasshopper version 1.0, or Grasshopper v1.0, prior to 2014 during the time the followon Grasshopper-class test vehicles were being built.
In addition to three test flights in 2012, five additional tests were successfully flown by the end of October 2013{{mdash}}including the fourth test overall in March 2013{{mdash}}in which Grasshopper doubled its highest leap to rise to {{convert|80.1|m|sp=us}} with a 34-second flight.<ref name="faa20130310">{{cite news |url=http://www.spacex.com/news/2013/03/23/grasshopper-completes-highest-leap-date |title=Grasshopper Completes Highest Leap to Date |work=SpaceX.com |date=March 10, 2013 |accessdate=April 21, 2013}}</ref> In the seventh test, in August 2013, the vehicle flew to {{convert|250|m|ft|sp=us}} during a 60-second flight and executed a {{convert|100|m|ft|sp=us|adj=on}} lateral maneuver before returning to the pad.<ref name="nbc20130814">{{cite news |url=http://www.nbcnews.com/science/spacexs-grasshopper-test-rocket-flies-sideways-successfully-6C10923106 |title=SpaceX's Grasshopper test rocket flies sideways successfully |work=NBC News |last=Boyle |first=Alan |date=August 14, 2013 |accessdate=August 15, 2013}}</ref> Grasshopper made its eighth and final test flight on October 7, 2013, flying to {{convert|744|m|sp=us}} (0.46 miles) before making its eighth successful landing.<ref name="sx20131012fb">{{cite video |url=https://www.youtube.com/watch?v=9ZDkItO-0a4 |title=Grasshopper flies to its highest height to date |publisher=SpaceX |date=October 12, 2013 |accessdate=April 9, 2016}}</ref> The Grasshopper test vehicle is now retired.<ref name="sn20131017">{{cite news |url=http://www.spacenews.com/article/launch-report/37740spacex-retires-grasshopper-new-test-rig-to-fly-in-december |title=SpaceX Retires Grasshopper, New Test Rig To Fly in December |work=Space News |last=Klotz |first=Irene |date=October 17, 2013 |accessdate=October 21, 2013}}</ref>
==== Falcon 9 Reusable Development Vehicle ====
As early as October 2012, SpaceX discussed development of a second-generation Grasshopper test vehicle, which was to have lighter landing legs that fold up on the side of the rocket, a different engine bay, and would be nearly 50% longer than the first Grasshopper vehicle.<ref name="nsw20121002">{{cite news |url=http://www.newspacewatch.com/articles/a-2nd-gen-grasshopper-a-new-video-of-first-hop.html |title=A 2nd-gen Grasshopper + A new video of first hop |work=NewSpace Watch |last=Lindsey |first=Clark |date=October 2, 2012 |accessdate=November 4, 2012 <!-- REMOVED https://archive.is/ archive link, as a wikibot reports that is is on some sort of "local blacklist". See page history on 2016-04-05 for more info |archiveurl=https://archive.is/20130104030313/http://www.newspacewatch.com/articles/a-2nd-gen-grasshopper-a-new-video-of-first-hop.html |archivedate=January 4, 2013 --> |subscription=yes}}</ref> In March 2013, SpaceX announced that the larger Grasshopper-class<!-- then referred to as ''Grasshopper v1.1'' --> suborbital flight vehicle would be constructed out of the {{nowrap|[[Falcon 9 v1.1]]}} first-stage tank that was used for qualification testing at the SpaceX Rocket Development and Test Facility in early 2013. It was rebuilt as the {{nowrap|F9R Dev1}} with extensible landing legs.
The second VTVL flight test vehicle—F9R Dev1, built on the much longer [[Falcon 9 v1.1]] first-stage tank, with retractable landing legs—made its first test flight on April 17, 2014.<ref name=nsf20140422/><ref name=wt20140417/> F9R Dev1 was used for low-altitude test flights in the McGregor, Texas area—projected maximum altitude below {{convert|10000|ft|order=flip|sp=us}}<ref name=nsf20140422/>—with a total of five test flights, all made during 2014.
This vehicle self-destructed as a safety measure during its fifth test flight on August 22, 2014.<ref>{{cite tweet |user=elonmusk |number=502974683864518657 |title=Three engine F9R Dev1 vehicle auto-terminated during test flight. No injuries or near injuries. Rockets are tricky … |date=August 22, 2014 |accessdate=April 9, 2016}}</ref>
By April 2014, a third flight test vehicle—F9R Dev2—was being built and was planned to be flown at the high-altitude test range available at [[Spaceport America]] in [[New Mexico]] where it was expected to be flown at altitudes up to {{convert|300000|ft|order=flip|sp=us}}-plus.<ref name=nsf20140422/> It was never flown as SpaceX moved the high-altitude testing program to its [[SpaceX Falcon 9 booster post-mission, controlled-descent, test program|controlled-descent testing of used boosters]] following their use on a paid orbital launch and ascent.
==== DragonFly ====
{{main|DragonFly (rocket)}}
[[DragonFly (rocket)|DragonFly]] is a prototype test article for a propulsively landed version of the [[SpaceX Dragon]] [[space capsule|capsule]], a [[suborbital spaceflight|suborbital]] [[reusable launch vehicle]] (RLV), intended for low-altitude [[flight test]]ing. It will undergo a test program in Texas at the McGregor Rocket Test Facility, in 2014–2015.<ref name=nbc20140521/><ref name=faa201311>{{cite web |last1=James |first1=Michael |last2=Salton |first2=Alexandria |last3=Downing |first3=Micah |title=Draft Environmental Assessment for Issuing an Experimental Permit to SpaceX for Operation of the Dragon Fly Vehicle at the McGregor Test Site, Texas, May 2014 – Appendices |publisher=Blue Ridge Research and Consulting, LCC |pages=12 |date=November 12, 2013 |url=http://www.faa.gov/about/office_org/headquarters_offices/ast/media/20140513_DragonFly_DraftEA_Appendices%28reduced%29.pdf}}</ref>
The DragonFly test vehicle is powered by eight [[SuperDraco]] engines, arranged in a redundant pattern to support [[fault-tolerance]] in the propulsion system design.<ref name=wt20140522/> SuperDracos utilize a [[storable propellant]] mixture of [[monomethyl hydrazine]] (MMH) [[fuel]] and [[nitrogen tetroxide]] [[oxidizer]] (NTO), the same propellants used in the much smaller [[Draco (rocket engine family)|Draco]] thrusters used for [[attitude control]] and [[Reaction control system|maneuvering]] on the first-generation [[Dragon spacecraft]].<ref name=faa201311/>
While SuperDraco engines are capable of {{convert|16400|lbf|N|order=flip}} of thrust, during use on DragonFly flight test vehicle each will be [[Rocket engine throttling|throttled]] to less than {{convert|15325|lbf|N|order=flip}} to maintain vehicle stability.<ref name=faa201311/>
A test flight program of thirty flights has been proposed, including two ''propulsive assist'' (parachutes plus thrusters) and two ''propulsive landing'' (no parachutes) on flights dropped from a helicopter at an altitude of approximately {{convert|10000|ft|m|sp=us|order=flip}}. The other 26 test flights are projected to take off from a [[launch pad|pad]]: eight to be ''propulsive assist hops'' (landing with parachutes plus thrusters) and 18 to be ''full propulsive hops'', similar to the [[Grasshopper (rocket)|Grasshopper]] and [[F9R Dev]] booster stage test flights.<ref name=faa201311/><ref name=wt20140522>
{{cite news |last=Abbott |first=Joseph |title=Grasshopper to DragonFly: SpaceX seeks approval for new McGregor testing |url=http://www.wacotrib.com/blogs/joe_science/grasshopper-to-dragonfly-spacex-seeks-approval-for-new-mcgregor-testing/article_11d0c40a-e1f6-11e3-a868-001a4bcf887a.html |accessdate=May 23, 2014 |newspaper=Waco Tribune |date=May 22, 2014}}</ref>
The DragonFly test program is not expected to start until after the completion of the [[F9R Dev1]] booster testing at the McGregor facility.<ref name=wt20140522/>
=== Falcon 9 booster post-mission flight tests ===
[[File:CRS-6 first stage booster landing attempt.jpg|thumb|upright=0.6|CRS-6 booster landing attempt]]
{{Main|Falcon 9 first-stage landing tests}}
In an arrangement unusual for launch vehicles, some first stages of the SpaceX Falcon 9 v1.1 rockets are being used for propulsive-return controlled-descent flight tests after they complete the boost phase of an orbital flight. These boosters would ordinarily just be discarded in the ocean after setting their payloads on their way. The over-water tests take place in the Pacific and Atlantic oceans south of [[Vandenberg Air Force Base]] and east of [[Cape Canaveral Air Force Station]]. The first flight test occurred on September 29, 2013, after the second stage with the [[CASSIOPE]] and [[nanosat]] payloads separated from the booster. These descent and simulated landing tests continued over the next two years, with the second flight test taking place on April 18, 2014,<ref name="bbc20130930" /><ref name="ut20140419" /><ref name=dn20140224/> and four subsequent tests conducted in 2015.<ref name=nsf20151231>
{{cite news |last1=Gebhardt |first1=Chris |title=Year In Review, Part 4: SpaceX and Orbital ATK recover and succeed in 2015 |url=http://www.nasaspaceflight.com/2015/12/yir4-spacex-orbital-atk-recover-succeed-2015/ |accessdate=January 1, 2016 |work=NASASpaceFlight.com |date=December 31, 2015}}</ref>
==== Re-entry and controlled descent development ====
Following analysis of the flight test data from the first booster-controlled descent in September 2013, SpaceX announced it had successfully tested a large amount of new technology on the flight, and that coupled with the technology advancements made on the Grasshopper low-altitude landing demonstrator, they were ready to test a full recovery of the booster stage. The first flight test was successful; SpaceX said it was "able to successfully transition from vacuum through [[hypersonic]], through [[supersonic]], through [[transonic]], and light the engines all the way and control the stage all the way through [the atmosphere]".<ref name=pm20130930>{{cite news |url=http://www.popularmechanics.com/science/space/rockets/musk-spacex-now-has-all-the-pieces-for-reusable-rockets-15985616 |title=Musk: SpaceX Now Has "All the Pieces" For Truly Reusable Rockets |work=Popular Mechanics |last=Belfiore |first=Michael |date=September 30, 2013 |accessdate=October 17, 2013}}</ref> Musk said, "the next attempt to recovery [sic] the Falcon 9 first stage will be on the fourth flight of the upgraded rocket. This would be [the] third commercial Dragon cargo flight to ISS."<ref name="pa20130930">{{cite news |url=http://www.parabolicarc.com/2013/09/29/falcon-9-launch-payloads-orbit-vandenberg/ |title=Falcon 9 Launches Payloads into Orbit From Vandenberg |work=Parabolic Arc |last=Messier |first=Doug |date=September 29, 2013 |accessdate=September 30, 2013}}</ref>
This second flight test took place during the April 2014 Dragon flight to the ISS. SpaceX attached [[Launch vehicle landing gear|landing legs]] to the first stage, decelerated it over the ocean and attempted a simulated landing over the water, following the ignition of the second stage on the [[SpaceX CRS-3|third cargo resupply mission]] contracted to NASA. The first stage was successfully slowed down enough for a soft landing over the Atlantic Ocean.<ref name="ut20140419" /> SpaceX announced in February 2014 the intent to continue the tests to land the first-stage booster in the ocean until precision control from hypersonic all the way through subsonic regimes has been proven.<ref name=dn20140224>{{cite news |last=Klotz |first=Irene |title=SpaceX Falcon Rocket to Test Landing Legs |url=http://news.discovery.com/space/private-spaceflight/spacex-falcon-rocket-to-test-precision-landing-legs-140224.htm |accessdate=February 25, 2014 |newspaper=Discovery News |date=February 24, 2014}}</ref>
Five additional controlled-descent tests were conducted in the remainder of 2014 through April 2015, including two attempts to land on a [[floating landing platform]]—a SpaceX-built [[Autonomous Spaceport Drone Ship]]—on the [[Atlantic Ocean]] east of the launch site, both of which brought the vehicle to the landing platform, but neither of which resulted in a successful landing.
==== First landing on ground pad ====
[[File:ORBCOMM-2_First-Stage_Landing_(23271687254).jpg|thumb|Falcon 9 Flight 20's first stage landing viewed from a helicopter, December 22, 2015.]]
During the [[SpaceX CRS-7|2015 launch hiatus]], SpaceX requested regulatory approval from the [[FAA]] to attempt returning their [[Falcon 9 Flight 20|next flight]] to [[CCAFS|Cape Canaveral]] instead of targeting a floating platform in the ocean. The goal was to [[VTVL|land the booster vertically]] at the leased ''[[Landing Zone 1]]'' facility—the former [[Launch Complex 13]] where SpaceX had recently built a large rocket landing pad.<ref name=ft201511201>
{{cite news |last1=Dean |first1=James |title=SpacexSpaceX wants to land next booster at Cape Canaveral |url=http://www.floridatoday.com/story/tech/science/space/spacex/2015/12/01/spacex-wants-land-next-booster-cape-canaveral/76576142/ |accessdate=December 2, 2015 |work=Florida Today |date=December 1, 2015}}</ref>
The FAA approved the safety plan for the ground landing on December 18, 2015.<ref name=os20151220>{{cite news |title=SpaceX aims for Sunday launch and ground landing |url=http://www.orlandosentinel.com/news/space/go-for-launch/os-spacex-engine-testing-sunday-launch-20151218-post.html |work=Orlando Sentinel |date=December 20, 2015 |accessdate=December 20, 2015}}</ref> The first stage landed successfully on target at 20:38 local time on December 21 (01:38 UTC on December 22).<ref>{{cite news |url=https://www.theverge.com/2015/12/21/10640306/spacex-elon-musk-rocket-landing-success |title=SpaceX successfully landed its Falcon 9 rocket after launching it to space |work=[[The Verge]] |first=Loren |last=Grush |date=December 21, 2015 |accessdate=April 9, 2016}}</ref><ref name=nsf20151231/>
SpaceX does not plan to fly the ''[[Falcon 9 Flight 20]]'' first stage again.<ref>{{cite news |url=https://www.theverge.com/2015/12/21/10642028/spacex-falcon-9-landing-elon-musk-wont-fly |title=SpaceX’s 'reusable' Falcon 9 rocket won’t fly again, Elon Musk says |work=[[The Verge]] |first=Sean |last=O'Kane |date=December 21, 2015 |access-date=December 23, 2015}}</ref> Rather, the rocket was moved a few miles north to the SpaceX hangar facilities at [[Launch pad 39A]], recently refurbished by SpaceX at the adjacent [[Kennedy Space Center]], where it was inspected before being used on January 15, 2016, to conduct a [[static fire]] test on its original launchpad, [[Launch Complex 40]].<ref>{{Cite news |url=http://www.universetoday.com/126837/spacex-test-fires-recovered-falcon-9-booster-major-step-reusable-rockets/ |title=SpaceX Test Fires Recovered Falcon 9 Booster in Major Step To Reusable Rockets - Universe Today |date=January 16, 2016 |newspaper=Universe Today |language=en-US |access-date=January 28, 2017}}</ref> This test aimed to assess the health of the recovered booster and the capability of this rocket design to fly repeatedly in the future.<ref name=f20-static-fire>{{cite web |url=http://spaceflight101.com/returned-falcon-9-booster-fires-up-for-static-fire-test/ |work=Spaceflight 101 |title=Returned falcon 9 booster fires up for static fire test |date=January 15, 2016 |accessdate=January 18, 2016}}</ref><ref name=nsf20151231/> The tests delivered good overall results except for one of the outer engines experiencing thrust fluctuations.<ref name=f20-static-fire /> Elon Musk reported that this may have been due to debris ingestion.<ref>{{cite news |title=SpaceX Tests Recovered Falcon 9 Stage and Prepares for Next Launch |url=http://spacenews.com/spacex-tests-recovered-falcon-9-stage-and-prepares-for-next-launch/ |date=January 15, 2016 |accessdate=January 15, 2016}}</ref>
[[File:First stage of Jason-3 rocket (24423604506).jpg|thumb|First stage of [[Falcon 9 Flight 21]] descending over the floating landing platform, January 17, 2016, immediately prior to a soft touchdown followed by [[deflagration]] of the rocket after a landing leg failed to latch, causing the rocket to tip over.]]
==== Near-misses on the oceans ====
[[Falcon 9 Flight 21]] launched the [[Jason-3]] satellite on January 17, 2016, and attempted to land on the [[autonomous spaceport drone ship|floating platform]] ''Just Read the Instructions'',<ref name=nbc20160107>
{{cite news |url=http://www.nbcnews.com/tech/innovation/spacex-plans-drone-ship-rocket-landing-jan-17-launch-n492471 |title=SpaceX Plans Drone Ship Rocket Landing for Jan. 17 Launch |publisher=[[NBC News]] |first=Devin |last=Coldewey |date=January 7, 2016 |access-date=January 8, 2016}}</ref> located for the first time about {{convert|200|mi|km}} out in the [[Pacific Ocean]].
<!-- press conference, Hans Koenigsmann speaking for SpaceX: they are not attempting the landing on the land landing site at VAFB SLC4W because they have not yet received approval from the regulatory authorities; will find a secondary source before adding to the article prose... --><!-- HK: they may try to give video coverage of the landing, but unsure they can do it from over the horizon, satellite links, etc. -->
Approximately 9 minutes into the flight, the live video feed from the drone ship went down due to the losing its lock on the uplink satellite.
The vehicle landed smoothly onto the vessel but one of the four landing legs failed to lock properly, reportedly due to ice from the heavy pre-launch [[fog]] preventing a lockout [[collet]] from latching.<ref name=sfn20160118>
{{cite web |title=SpaceX narrowly misses booster landing at sea |work=Spaceflight Now |url=https://spaceflightnow.com/2016/01/18/spacex-narrowly-misses-booster-landing-at-sea/ |date=January 18, 2016 |access-date=January 18, 2016 |first=Stephen |last=Clark}}</ref>
Consequently the booster fell over shortly after touchdown and was destroyed in a [[deflagration]] upon impact with the pad.<ref name=gw20160117>
{{cite news |last=Boyle |first=Alan |url=http://www.geekwire.com/2016/spacex-launches-jason-3-satellite-then-tries-landing-falcon-9-rocket-at-sea/ |title=SpaceX rocket launches satellite, but tips over during sea landing attempt |work=GeekWire |date=January 17, 2016 |accessdate=January 18, 2016}}</ref><ref name=rud>{{cite web |url=https://www.instagram.com/p/BAqirNbwEc0/ |title=Flight 21 landing and breaking a leg |work=Instagram |first=Elon |last=Musk |author-link=Elon Musk |date=January 17, 2016}}</ref>
[[Falcon 9 Flight 22|Flight 22]] was carrying a heavy payload of {{convert|5271|kg|sigfig=2}} to [[geostationary transfer orbit]] (GTO). This was heavier than previously advertised maximum lift capacity to GTO being made possible by going slightly [[subsynchronous orbit|subsynchronous]]. Following delays caused by failure of [[Falcon 9 Flight 19|Flight 19]] SpaceX agreed to provide extra thrust to the [[SES-9]] satellite to take it [[supersynchronous orbit|supersynchronous]].<ref name=sfn20160224>
{{cite news |last=Clark |first=Stephen |url=http://spaceflightnow.com/2016/02/24/falcon-9-rocket-to-give-ses-9-telecom-satellite-an-extra-boost/ |title=Falcon 9 rocket to give SES 9 telecom satellite an extra boost |work=Spaceflight Now |date=February 24, 2016 |accessdate=March 7, 2016 |quote=''SES’s contract with SpaceX called for the rocket to deploy SES 9 into a “sub-synchronous” transfer orbit with an apogee around 16,155 miles (26,000 kilometers) in altitude. Such an orbit would require SES 9 to consume its own fuel to reach a circular 22,300-mile-high perch, a trek that Halliwell said was supposed to last 93 days. The change [SpaceX offered] in the Falcon 9’s launch profile will put SES 9 into an initial orbit with an apogee approximately 24,419 miles (39,300 kilometers) above Earth, a low point 180 miles (290 kilometers) up, and a track tilted about 28 degrees to the equator''}}</ref>
As a result of these factors, there was little propellant left to execute a full reentry and landing test with normal margins. Consequently the Falcon 9 first stage followed a [[ballistic trajectory]] after separation and re-entered the atmosphere at high velocity, making it less likely to land successfully.<ref name=sxPressKit20160223>{{cite web |url=http://www.spacex.com/sites/spacex/files/spacex_ses9_press_kit_final.pdf |format=PDF |title=SES-9 Mission |work=Press Kit |publisher=SpaceX |date=February 23, 2016 |accessdate=February 24, 2016 |quote=This mission is going to a Geostationary Transfer Orbit. Following stage separation, the first stage of the Falcon 9 will attempt an experimental landing on the “Of Course I Still Love You” droneship. Given this mission’s unique GTO profile, a successful landing is not expected.}}</ref><ref name=sfn20160224/> The [[atmospheric re-entry]] and controlled descent were successful despite the higher aerodynamical constraints on the first stage due to extra speed. However the rocket was moving too fast and was destroyed when it collided with the drone ship. SpaceX collected valuable data on the extended flight envelope required to recover boosters from GTO missions.
==== Landings at sea ====
{{main| Autonomous spaceport drone ship | SpaceX CRS-8 | JCSAT-2B}}
[[File:CRS-8 (26239020092).jpg|thumb|right|First stage of Falcon 9 Flight 23 landed on autonomous droneship]]
Starting in January 2015, SpaceX positioned stable floating platforms a few hundred miles off the coast along the rocket trajectory; those transformed barges were called [[autonomous spaceport drone ship]]s.<ref name=nsf20141124>{{cite news |last1=Bergin |first1=Chris |title=SpaceX's Autonomous Spaceport Drone Ship ready for action |url=http://www.nasaspaceflight.com/2014/11/spacex-autonomous-spaceport-drone-ship/ |accessdate=24 November 2014 |work=NasaSpaceFlight.com |date=24 November 2014}}</ref> On April 8, 2016, Falcon 9 Flight 23, the third flight of [[Falcon 9 full thrust|the full-thrust version]], delivered the [[SpaceX CRS-8]] cargo on its way to the [[International Space Station]] while the [[Falcon 9 booster B1021|first stage]] conducted a boostback and re-entry maneuver over the Atlantic ocean. Nine minutes after liftoff, the booster landed vertically on the drone ship ''[[Of Course I Still Love You]]'', 300 km from the Florida coastline, achieving a long-sought-after milestone for the SpaceX reusability development program.<ref name=flight23>{{cite news |url=http://phenomena.nationalgeographic.com/2016/04/08/spacex-rocket-makes-spectacular-landing-on-drone-ship/ |title=SpaceX Rocket Makes Spectacular Landing on Drone Ship |publisher=[[National Geographic Society|National Geographic]] |first=Nadia |last=Drake |date=April 8, 2016 |accessdate=April 8, 2016 |quote=To space and back, in less than nine minutes? Hello, future.}}</ref>
A second successful drone ship landing occurred on May 6, 2016, with the next flight which launched [[JCSAT-14]] to GTO. This second landing at sea was more difficult than the previous one because the booster at separation was traveling about {{convert|8350|km/h|abbr=on}} compared to {{convert|6650|km/h|abbr=on}} on the CRS-8 launch to [[low Earth orbit]].<ref>[https://www.youtube.com/watch?v=7pUAydjne5M You tube JCSat 14 hosted webcast]</ref><ref>[https://www.youtube.com/watch?v=7pUAydjne5M You tube CRS8 hosted webcast]</ref> Pursuing their experiments to test the limits of the flight envelope, SpaceX opted for a shorter landing burn with three engines instead of the single-engine burns seen in earlier attempts; this approach consumes less fuel by leaving the stage in free fall as long as possible and decelerating more sharply, thereby minimizing the amount of energy expended to counter gravity.<ref name=musk-tweet-20160506>
{{cite tweet |user=elonmusk |author-link=Elon Musk |number=728462267893698561 |date=May 6, 2016 |access-date=May 8, 2016 |title=Yeah, this was a three engine landing burn, so triple deceleration of last flight. That's important to minimize gravity losses.}}</ref> Elon Musk indicated this first stage may not be flown again instead being used as a life leader for ground tests to confirm others are good.<ref>[http://www.floridatoday.com/story/tech/science/space/spacex/2016/05/16/landed-spacex-rocket-suffered-max-damage/84454230/ Florida Today Landed spacex rocket suffered max damage]</ref>
A third successful landing followed on 27 May, again following deceleration from the high speed required for a GTO launch. The landing crushed a "crush core" in one leg, leading to a notable tilt to the stage as it stood on the drone ship.<ref name="space.com"/>
==== Routine procedure ====
{{Main|List of Falcon 9 and Falcon Heavy launches}}
Over the subsequent missions, landing of the first stage gradually became a routine procedure, and since January 2017 SpaceX ceased to refer to their landing attempts as "experimental". Low-energy missions to the [[ISS]] fly back to the launch site and land at [[Landing Zone 1|LZ-1]], whereas more demanding satellite missions land on drone ships a few hundred miles downrange. Occasional missions with heavy payloads, such as [[EchoStar 23]], do not attempt to land, flying in [[Expendable launch system|expendable]] configuration without fins and legs.
Further successful landings occurred:
* on the LZ-1 ground pad: [[CRS-9]] on 18 July 2016, [[CRS-10]] on 19 February 2017, [[NROL]]-76 on 1 May, [[CRS-11]] on 3 June, [[CRS-12]] on 14 August, [[Boeing X-37B|Boeing X-37B OTV-5]] on 7 September, [[CRS-13]] on 15 December, and [[Zuma (satellite)|Zuma]] on 8 January 2018.<!-- UPDATE after each recovery on land -->
* on drone ships: [[JCSAT-16]] on 14 August 2016, [[Iridium NEXT]]-1 on 14 January 2017, [[SES-10]] on 30 March and [[BulgariaSat-1]] on 23 June (first and second recoveries of re-flown boosters), [[Iridium NEXT]]-2 on 25 June, [[Formosat-5]] on 24 August, [[Iridium NEXT]]-3 on 9 October, [[SES-11]]/[[EchoStar 105]] on 11 October, and [[Koreasat 5A]] on 30 October 2017.<!-- UPDATE after each recovery at sea -->
==== Future tests ====
{{main article| List of Falcon 9 first-stage boosters | List of Falcon 9 and Falcon Heavy launches#Future launches}}
During 2016 and 2017, SpaceX has recovered a number of first stages to both land and drone ships, helping them optimize the procedures needed to re-use the boosters rapidly. In January 2016 Elon Musk estimated the likelihood of success at 70 percent for all landing attempts in 2016, hopefully rising to 90 percent in 2017; he also cautioned that we should expect "a few more RUDs" (''Rapid Unscheduled Disassembly'', Musk's euphemism to denote destruction of the vehicle on impact).<ref>{{cite tweet |user=elonmusk |author-link=Elon Musk |number=689299216607232000 |date=January 19, 2016 |title=My best guess for 2016: ~70% landing success rate (so still a few more RUDs to go), then hopefully improving to ~90% in 2017}}</ref> Musk's prediction was vindicated, as 5 out of 8 flown boosters ({{percent|5|8}}) were recovered in 2016, and 14 out of 14 ({{percent|14|14}}) in 2017. Three GTO missions for heavy payloads ([[EchoStar#Satellite fleet|EchoStar 23]] in March 2017, [[Inmarsat-5 F4]] in May 2017 and [[Intelsat 35e]] in July 2017) were flown in an [[expendable launch system|expendable]] configuration, not equipped for landing. One booster which could have been recovered was intentionally flown without legs and left to sink after a soft touchdown in the ocean (booster B1036 for the [[Iridium NEXT]] 31–40 mission in December 2017).
Since late 2017, incremental testing with refinements to the fairing recovery design have been conducted. SpaceX has indicated that they expected to recover an intact fairing in 2017, and to fly a recovered fairing in 2018.<ref name=issR&Dconf20170719-14:15/> {{As of|December 2017}}, no official information on progress in the fairing recovery process was available.
=== First-stage reuse ===
{{As of|2018|02|06}}, SpaceX had [[List of Falcon 9 first-stage boosters|recovered 17 first-stage boosters from previous missions]], of which six were recovered twice, yielding a total 23 landings. In 2017, SpaceX flew a total of 5 missions out of 20 with re-used boosters ({{percent|5|20}}). In total, eight boosters have been re-flown {{as of|February 2018|lc=y}}.
On July 28, 2016, the first stage from the [[JCSAT-2B]] mission was successfully test-fired for a full duration at the SpaceX McGregor facility.<ref>{{cite video |url=https://www.youtube.com/watch?v=SZQY902xQcw |title=Landed Falcon 9 First Stage Test Firing |publisher=SpaceX |date=July 28, 2016}}</ref> The first reuse attempt occurred on 30 March 2017<ref name="SpaceflightNowSchedule">{{Cite web|url=https://spaceflightnow.com/2017/03/30/ses-10-mission-status-center/|title=Live coverage: SpaceX aims for Thursday launch of previously-flown rocket - Spaceflight Now|last=|first=|date=|website=|access-date=March 31, 2017}}</ref> with the launch of [[SES-10]],<ref>{{cite news |url=http://www.latimes.com/business/la-fi-spacex-rocket-20160829-snap-story.html |title=SpaceX signs first customer for launch of a reused rocket |newspaper=[[Los Angeles Times]] |first=Samantha |last=Masunaga |date=August 30, 2016}}</ref> resulting in a successful flight and second landing of the [[Falcon 9 booster B1021|B1021 first stage]] recovered from the [[SpaceX CRS-8|CRS-8]] mission of April 2016.<ref>{{cite news |url=http://www.satellitetoday.com/nextspace/2016/08/30/ses-becomes-first-reusable-rocket-customer-spacex/ |title=SES Becomes First Reusable Rocket Customer for SpaceX |work=Via Satellite |first=Caleb |last=Henry |date=August 30, 2016}}</ref> Another reflight succeeded in June 2017 with [[BulgariaSat-1]] riding the [[B1029]] booster from the January 2017 [[Iridium NEXT]] mission.<ref name=nsf-20170623>{{cite news |url=https://www.nasaspaceflight.com/2017/06/spacex-falcon-9-second-flight-bulgariasat-1-mission/ |title=SpaceX Falcon 9 success with second flight involving BulgariaSat-1 mission |work=[[NASASpaceFlight.com]] |first=William |last=Graham |date=June 23, 2017 |access-date=June 25, 2017}}</ref> Booster B1031 flew the [[CRS-10]] mission to the [[ISS]] in February 2017 and helped loft communications satellite [[SES-11]] to [[geostationary orbit]] in October 2017. Boosters B1035 and B1036 were flown twice each for the same customer, B1035 for [[NASA]] missions [[CRS-11]] and [[CRS-13]] in June and December 2017, and B1036 for two batches of 10 [[Iridium NEXT]] satellites, also in June and December 2017. B1032 was re-used for [[GovSat-1]] in January 2018 after [[NROL-76]] in May 2017. Finally, B1023 and B1025 were re-used as side boosters on the [[Falcon Heavy test flight]] in February 2018.
SpaceX spent four months refurbishing the first booster to be re-used, [[B1021]], and launched it again after approximately one year.<ref>{{cite news|url= https://spaceflightnow.com/2017/03/27/hotfire-test-completed-ahead-of-milestone-falcon-9-launch-thursday/ |work= Spaceflight Now |title= Hotfire test completed ahead of milestone Falcon 9 launch Thursday |first= Stephen |last= Clark |date= 2017-03-27 |accessdate= 2017-04-01 }}</ref> The second booster to be flown again, [[B1029]], was refurbished in "only a couple of months"<ref name=sir-20170626 /> and re-launched after five months.<ref name=nsf-20170623 /> Elon Musk has stated a goal to turn around a first stage within 24 hours before the end of 2017,<ref>{{cite news |url= http://www.telegraph.co.uk/news/2017/03/31/spacex-makes-history-successfully-launching-first-recycled-rocket/ |newspaper= [[The Daily Telegraph]] |agency= [[Reuters]] |title= SpaceX makes history by successfully launching first recycled rocket booster |date= 2017-03-31 |accessdate= 2017-04-01}}</ref> but that did not happen.
Boosters [[B1019]] and [[B1021]] were retired and put on display. [[B1029]] was also retired after the [[BulgariaSat-1]] mission.<ref>{{cite web|title=List of Falcon 9 first-stage boosters|url=https://en.wikipedia.org/wiki/List_of_Falcon_9_first-stage_boosters|accessdate=26 November 2017}}</ref>{{Better source|reason=per WP:CIRCULAR|date=February 2018}} B1023, B1025, B1031 and B1035 were recovered a second time, while B1032 and B1036 was voluntarily sunk at sea after a soft ocean touchdown.
=== Fairing reuse ===
On March 30, 2017 as part of the [[SES-10]] mission, SpaceX for the first time performed a controlled landing of the payload fairing, using thrusters to properly orient the fairing during atmospheric reentry and a steerable parachute to achieve an intact splashdown.<ref name=verge20170330/><ref name=sn20170330/> With the aim of full reuse, it is planned that fairings will land on a structure jokingly described by Musk as a "floating bouncy-castle".<ref name=floridatoday_26216836069515264/>
With successive tests and refinements on a number of flights, intact fairing recovery was stated as a goal for 2017, with reflight of a recovered fairing planned in 2018.<ref name=issR&Dconf20170719-14:15/>
The "bouncy castle" idea has been superseded by a net strung between large arms. This system, installed on ''Mr. Steven'' (a fast [[platform supply vessel]] equipped with [[dynamic positioning]] systems), was tested on the launch of the [[Paz (satellite)|Paz]] satellite from [[Vandenberg Air Force Base]] [[Vandenberg AFB Space Launch Complex 4#SLC-4E|Space Launch Complex 4E]] in February 2018.<ref name=techcrunch20180220>{{cite news|last1=Etherington|first1=Darrell|title=SpaceX to use a net boat called ‘Mr. Steven’ to recover next rocket fairing|url=https://techcrunch.com/2018/02/20/spacex-to-use-a-net-boat-called-mr-steven-to-recover-next-rocket-fairing/|accessdate=February 20, 2018|work=TechCrunch|date=February 20, 2018|language=en}}</ref><ref name="nsf-20180225">{{cite news|last1=Baylor|first1=Michael|title=SpaceX’s Mr. Steven, the FSV fairing catcher – NASASpaceFlight.com|url=https://www.nasaspaceflight.com/2018/02/spacexs-mr-steven-fsv-fairing-catcher/|accessdate=February 26, 2018|work=NASASpaceFlight.com|date=February 25, 2018}}</ref> This mission also introduced a version 2 fairing, explicitly designed to "improve survivability for post-launch recovery attempts, and to be reusable on future missions".<ref name="nsf-20180220">{{cite news|last1=Graham|first1=William|title=SpaceX Falcon 9 set for PAZ launch with Starlink demo and new fairing – NASASpaceFlight.com|url=https://www.nasaspaceflight.com/2018/02/spacex-falcon-9-paz-launch-starlink-demo-new-fairing/|accessdate=February 21, 2018|work=NASASpaceFlight.com|date=February 20, 2018}}</ref>. This recovery attempt was not fully successful; the fairing missed the boat by a few hundred meters but landed intact in the water<ref>{{cite web|last1=Musk|first1=Elon|title=Missed by a few hundred meters, but fairing landed intact in water. Should be able catch it with slightly bigger chutes to slow down descent.|url=https://twitter.com/elonmusk/status/966692641533390848|publisher=Twitter|accessdate=22 February 2018|language=en|date=2018}}</ref> before being recovered and taken back to port.<ref name="nsf-20180225" />
=== Second-stage reuse ===
SpaceX also intends to experiment with second stage recovery on selected Falcon 9 flights. Together with the recovery of the payload fairing, this achievement would eventually enable full reusability of the rocket family.<ref name=issR&Dconf20170719-14:15/>
== Operational flow ==
In the first year of successful stage return from the experimental test flights, SpaceX performed ''[[ad hoc]]'' and flight-specific evaluation and component testing on each successfully landed stage. Stages were processed and initially evaluated in either launch hangars, or for Cape Canaveral landings, in the new hangar SpaceX recently completed at [[Kennedy Space Center Launch Complex 39]]. Returned rocket parts have also been transported to [[SpaceX Hawthorne]] and [[SpaceX McGregor]] for engineering evaluation and testing.
In February 2017, after eight rocket cores had successfully landed — seven of them having launched from Cape Canaveral — SpaceX announced plans to expand their physical facilities to process and refurbish rockets. They will do so in both leased space and in a new building to be built in [[Port Canaveral]], [[Florida]], near the location where the Atlantic [[Autonomous Spaceport Drone Ship]] is berthed, and where stages that land on the [[East Coast of the United States|east-coast]] droneship are now removed from the ship.<ref name=ft20160824>
{{cite news |url=http://www.floridatoday.com/story/tech/science/space/spacex/2016/08/24/spacex-lease-building-port-canaveral-build-another-one/89230076/ |title=SpaceX to lease building at Port Canaveral, build another one |work=[[Florida Today]] |date=August 24, 2016 |accessdate=August 24, 2016}}</ref>
== See also ==
{{Portal|Spaceflight}}
* [[Blue Origin]] [[New Shepard]], a sub-orbital VTVL system
== References ==
{{Reflist|30em}}' |
