SpaceX reusable launch system development program: Difference between revisions

Revision as of 01:27, 30 November 2024

Revision as of 11:14, 13 December 2024

Line 92:

* New [[Spacecraft attitude control|attitude control]] technology for the booster 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 |url=https://www.youtube.com/watch?v=XtNgWK4mm0M |title=Singapore Satellite Industry Forum 2013 – Opening Keynote |date=June 17, 2013 |language=en |access-date=April 9, 2016 |people=Gwynne Shotwell}}</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 |url=http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 |title=Broadcast 2212: Special Edition, interview with Gwynne Shotwell |date=March 21, 2014 |medium=audio file |language=en |publisher=The Space Show |time=51;50–52;55 |access-date=March 22, 2014 |archive-url=https://web.archive.org/web/20140322013556/http://archived.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 |archive-date=March 22, 2014 |url-status=dead |format=mp3 |id=2212 |people=Gwynne Shotwell}}</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|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 webnews |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 |publishernewspaper=SpaceX |access-date=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. |archive-date=December 17, 2014 |archive-url=https://web.archive.org/web/20141217062424/http://www.spacex.com/news/2014/12/16/x-marks-spot-falcon-9-attempts-ocean-platform-landing |url-status=live |last1=Post |first1=Hannah }}<!-- 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 have been used on all reusable Block 5 Falcon 9 first stages since May 2018.<ref>{{cite web|url=https://www.nasaspaceflight.com/2017/06/spacex-falcon-9-iridium-next-2-launch/|title=SpaceX Doubleheader Part 2 – Falcon 9 conducts Iridium NEXT-2 launch – NASASpaceFlight.com|website=www.nasaspaceflight.com|date=June 25, 2017|access-date=July 4, 2017|archive-date=November 11, 2020|archive-url=https://web.archive.org/web/20201111202928/https://www.nasaspaceflight.com/2017/06/spacex-falcon-9-iridium-next-2-launch/|url-status=live}}</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]]

* The [[Rocket engine throttling|rocket engine needs to be throttleable]] to achieve zero velocity at the same time the rocket reaches the ground. Even the lowest possible thrust of a single [[Merlin 1D]] engine exceeds the weight of the nearly empty Falcon 9 booster core, therefore the rocket cannot hover.<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/ |access-date=March 18, 2014 |newspaper=Flightglobal |date=March 21, 2013 |archive-date=October 30, 2013 |archive-url=https://web.archive.org/web/20131030135922/http://www.flightglobal.com/news/articles/spacex-merlin-1d-qualified-for-flight-383738/ |url-status=live }}</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 |access-date=March 18, 2014 |date=March 12, 2014 |archive-date=November 11, 2020 |archive-url=https://web.archive.org/web/20201111220657/https://www.spacelaunchreport.com/falcon9v1-1.html |url-status=live }}</ref><ref name=blackmore2016/>

Line 100:

* A large [[floating landing platform]] for launches where the first stage does not have sufficient fuel to return to the launch site. As of 2022, SpaceX built three [[autonomous spaceport drone ship]]s, one operating the West coast and two on the East coast of the United States.

* A [[thermal protection system]] to avoid damage to the first stage when re-entering the atmosphere.<ref>{{cite news|url=https://spaceflightnow.com/2018/05/11/spacex-debuts-an-improved-human-rated-model-of-the-falcon-9-rocket/|title=SpaceX debuts new model of the Falcon 9 rocket designed for astronauts|date=11 May 2018|access-date=August 23, 2019|archive-date=April 1, 2021|archive-url=https://web.archive.org/web/20210401055341/https://spaceflightnow.com/2018/05/11/spacex-debuts-an-improved-human-rated-model-of-the-falcon-9-rocket/|url-status=live}}</ref>

* 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 |access-date=January 15, 2017 |archive-date=January 10, 2017 |archive-url=https://web.archive.org/web/20170110121559/http://web.mit.edu/larsb/www/nae_bridge_2016.pdf |url-status=live }}</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 webnews |url=http://www.spacex.com/news/2013/03/26/landing-leg |title=Landing Legs |work=SpaceX.com |date=July 29, 2013 |access-date=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. |archive-date=May 20, 2015 |archive-url=https://web.archive.org/web/20150520100337/http://www.spacex.com/news/2013/03/26/landing-leg |url-status=live |last1=Shanklin |first1=Emily }}</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 |access-date=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. |archive-date=June 11, 2015 |archive-url=https://web.archive.org/web/20150611163359/http://www.spacex.com/news/2013/04/12/falcon-heavy-landing-legs |url-status=dead }}</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 |access-date=May 2, 2013 <!--REMOVED https://archive.today/ 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 -->|archive-url=https://archive.today/20130630001715/http://www.newspacewatch.com/articles/spacex-shows-a-leg-for-the-quotf-ninerquot.html |archive-date=June 30, 2013 |url-status=live |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. |url-access=subscription}}</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/ |access-date=May 10, 2014 |newspaper=NASAspaceflight.com |date=February 28, 2014 |archive-date=June 1, 2014 |archive-url=https://web.archive.org/web/20140601134441/http://www.nasaspaceflight.com/2014/02/spacex-crs-3-landing-legs-plan-first-stage-recovery-ambitions/ |url-status=live }}</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 |access-date=June 7, 2016 |date=June 7, 2016 |archive-date=June 8, 2016 |archive-url=https://web.archive.org/web/20160608132146/http://www.space.com/33102-spacex-leaning-rocket-comes-ashore-photos.html |url-status=live }}</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. |archive-date=September 3, 2017 |archive-url=https://web.archive.org/web/20170903090316/https://twitter.com/elonmusk/status/736328917317910528?lang=en |url-status=live }}</ref>

== Economics of rocket reuse ==