{{Short description|Spacecraft launch-escape system}}
{{Infobox rocket stage|name=Crew Dragon Launch Abort System|manufacturer=SpaceX|country=United States|status=Operational|engines=8 × SuperDraco (4 × pairs of 2)<ref>{{Cite web |last=Rauf |first=Jim |date=2023-10-19 |title=SpaceX Dragon Spacecraft |url=https://www.uc.edu/content/dam/refresh/cont-ed-62/olli/fall-23-class-handouts/SpaceX%205Dragon%20Capsules.pdf |url-status=live |archive-url=https://web.archive.org/web/20240819152114/https://www.uc.edu/content/dam/refresh/cont-ed-62/olli/fall-23-class-handouts/SpaceX%205Dragon%20Capsules.pdf |archive-date=2024-08-19 |access-date=2024-10-02 |website=uc.edu}}</ref>|thrust=71 kN|time=25 seconds|fuel={{chem2|N2O4|link=Dinitrogen tetroxide}} / {{chem2|CH6N2|link=Monomethylhydrazine}}|image=Crew Dragon Pad Abort Test (16814592054).jpg|caption=Crew Dragon prototype DragonFly<ref>{{Cite news |date=2014-05-21 |title=Elon Musk's SpaceX Plans DragonFly Landing Tests |url=https://www.nbcnews.com/science/space/elon-musks-spacex-plans-dragonfly-landing-tests-n111386 |url-status=live |archive-url=https://web.archive.org/web/20240820202210/https://www.nbcnews.com/science/space/elon-musks-spacex-plans-dragonfly-landing-tests-n111386 |archive-date=2024-08-20 |access-date=2024-10-02 |website=NBC News |language=en}}</ref> performing a pad abort demonstration.}}
The '''Crew Dragon Launch Abort System''' is designed to propel the SpaceX Crew Dragon spacecraft away from a failing launch vehicle. It is equipped with 8 SuperDraco engines, each capable of generating 71 kN of thrust.<ref name=":0">{{Cite web |last=SpaceX |title=SpaceX Dragon Overview |url=https://www.spacex.com/vehicles/dragon/ |url-status=live |archive-url=https://web.archive.org/web/20240930203607/https://www.spacex.com/vehicles/dragon/ |archive-date=2024-09-30 |access-date=2024-10-02 |website=SpaceX.com}}</ref><ref>{{Cite news|last=Berger |first=Eric |date=2016-04-30 |title=From zero to 100mph in 1.2 seconds, the SuperDraco thruster delivers |url=https://arstechnica.com/science/2016/04/meet-spacexs-superdraco-thruster-the-key-to-landing-a-dragon-on-mars/ |url-status=live |archive-url=https://web.archive.org/web/20240926003158/https://arstechnica.com/science/2016/04/meet-spacexs-superdraco-thruster-the-key-to-landing-a-dragon-on-mars/ |archive-date=2024-09-26 |access-date=2024-10-02 |website=Ars Technica |language=en-us}}</ref>
The abort system has several modes, or procedures for performing an abort in different phases of flight, including a pad abort, an in-flight abort, and the ability to use the abort system to fly into a lower than expected orbit should a failure occur late in flight.
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== Design == thumb|328x328px|A figure showing the Apollo spacecraft's launch abort system. [[File:Dragon 2 DM-2 03.jpg|thumb|425x425px|A diagram showing the configuration of Crew Dragon ''Endeavor'' during the Demo-2 mission.]] Traditionally, spacecraft like Apollo and Soyuz have utilized solid-fueled "puller" launch escape systems, with the main spacecraft beneath a protective fairing attached to the escape system. Once in space, the escape system and the fairing are jettisoned, with the spacecraft's mode of abort switched to using its orbital maneuvering thrusters or upper stages.<ref>{{cite web|last=Gilbert |first=Michael G. |date=2015-01-09 |title=THE MAX LAUNCH ABORT SYSTEM – CONCEPT, FLIGHT TEST, AND EVOLUTION |url=https://ntrs.nasa.gov/api/citations/20150000590/downloads/20150000590.pdf |url-status=live |archive-url=https://web.archive.org/web/20240930220430/https://ntrs.nasa.gov/api/citations/20150000590/downloads/20150000590.pdf |archive-date=2024-09-30 |access-date=2024-10-02 |website=NASA Technical Reports Server |language=en}}</ref><ref>{{Cite news|last=Weitering |first=Hanneke |date=2019-04-24 |title=The Emergency Launch Abort Systems of SpaceX and Boeing Explained |url=https://www.space.com/launch-abort-systems-of-spacex-boeing.html |url-status=live |archive-url=https://web.archive.org/web/20240926003158/https://www.space.com/launch-abort-systems-of-spacex-boeing.html |archive-date=2024-09-26 |access-date=2024-10-02 |website=Space.com |language=en}}</ref> Crew Dragon, however, has its abort system permanently attached to the sides of the spacecraft.<ref name=":0" />
Part of the reasoning behind this design is that it was originally planned to land dragon propulsively using the launch abort system.<ref>{{cite web|last1=Karcz |last2=Davis |last3=Aftosmis |last4=Allen |last5=Bakhtian |last6=Dyakanov |last7=Glass |last8=Gonzales |last9=Heldmann |last10=Lemke |last11=Marinova |last12=McKay |last13=Stoker |last14=Wooster |last15=Zarchi |date=2012-05-10 |title=RED DRAGON: LOW-COST ACCESS TO THE SURFACE OF MARS USING COMMERCIAL CAPABILITIES |url=https://ntrs.nasa.gov/api/citations/20120013431/downloads/20120013431.pdf |url-status=live |archive-url=https://web.archive.org/web/20240521011014/https://ntrs.nasa.gov/api/citations/20120013431/downloads/20120013431.pdf |archive-date=2024-05-21 |access-date=2024-10-02 |website=NASA Technical Reports Server}}</ref> These plans were dropped after skepticism from NASA and the cancellation of SpaceX's Red Dragon capsule.<ref>{{Cite news|last=Foust |first=Jeff |date=2017-07-19 |title=SpaceX drops plans for powered Dragon landings |url=https://spacenews.com/spacex-drops-plans-for-powered-dragon-landings/ |access-date=2024-10-02 |website=SpaceNews |language=en-US}}</ref> However, the capability was introduced on Crew-8, though only in the event of a parachute failure.<ref>{{Cite news|last=Clark |first=Stephen |date=2024-09-28 |title=SpaceX launches mission to bring Starliner astronauts back to Earth |url=https://arstechnica.com/space/2024/09/spacex-set-to-launch-mission-to-bring-starliner-astronauts-back-to-earth/ |access-date=2024-10-23 |website=Ars Technica |language=en-US}}</ref> Additionally, the ability to keep the abort system attached to the rocket throughout the entire ascent rather than jettisoning the launch escape system after stage separation allows for an abort capability in all stages of flight, increasing crew safety.<ref>{{Cite news|last=Harwood |first=William |date=2020-05-27 |title=SpaceX Crew Dragon abort system a major boost for crew safety - CBS News |url=https://www.cbsnews.com/news/spacex-nasa-launch-abort-rescue-scenarios/ |url-status=live |archive-url=https://web.archive.org/web/20240930224608/https://www.cbsnews.com/news/spacex-nasa-launch-abort-rescue-scenarios/ |archive-date=2024-09-30 |access-date=2024-10-02 |website=cbsnews.com |language=en-US}}</ref>
Crew Dragon's "trunk", or cargo bay, also plays an important role in the abort sequence. Rather than leaving the trunk with the rocket like Apollo or Soyuz, Dragon keeps the trunk attached during an abort for aerodynamic stability.<ref>{{Cite web |last1=Jordan |first1=Gary |last2=Reed |first2=Benji |date=2019-09-27 |title=The SpaceX Crew Dragon - NASA |url=https://www.nasa.gov/podcasts/houston-we-have-a-podcast/the-spacex-crew-dragon/ |url-status=live |archive-url=https://web.archive.org/web/20240927053240/https://www.nasa.gov/podcasts/houston-we-have-a-podcast/the-spacex-crew-dragon/ |archive-date=2024-09-27 |access-date=2024-10-02 |website=NASA - Houston, we have a podcast |language=en-US}}</ref>
== History ==
=== Pad Explosion === On 20 April 2019, Crew Dragon C204 was destroyed in an incident while testing its SuperDraco engines. A video leaked shortly after the incident shows the capsule exploding on a launch mount.<ref>{{Cite news|last=Berger |first=Eric |date=2019-04-22 |title=Here's what we know, and what we don't, about the Crew Dragon accident |url=https://arstechnica.com/science/2019/04/heres-what-we-know-and-what-we-dont-about-the-crew-dragon-accident/ |url-status=live |archive-url=https://web.archive.org/web/20240819032640/https://arstechnica.com/science/2019/04/heres-what-we-know-and-what-we-dont-about-the-crew-dragon-accident/ |archive-date=2024-08-19 |access-date=2024-10-02 |website=Ars Technica |language=en-us}}</ref><ref>{{Cite news|author1=Mathewson |first=Samantha |date=2019-05-01 |title=NASA Workers Warned About Sharing Images After SpaceX Explosion Video Leak: Report |url=https://www.space.com/spacex-crew-dragon-explosion-nasa-memo.html |url-status=live |archive-url=https://web.archive.org/web/20240613101133/https://www.space.com/spacex-crew-dragon-explosion-nasa-memo.html |archive-date=2024-06-13 |access-date=2024-10-02 |website=Space.com |language=en}}</ref> NASA and SpaceX confirmed the explosion and stated that there were no injuries.<ref>{{Cite news|last=Ryan |first=Jackson |date=2019-04-25 |title=NASA urges patience as SpaceX investigates the Crew Dragon explosion |url=https://www.cnet.com/science/nasa-urges-patience-as-spacex-investigates-the-crew-dragon-explosion/ |url-status=live |archive-url=https://web.archive.org/web/20231130211317/https://www.cnet.com/science/nasa-urges-patience-as-spacex-investigates-the-crew-dragon-explosion/ |archive-date=2023-11-30 |access-date=2024-10-02 |website=CNET |language=en}}</ref> [[File:Vertical Ball check valve.jpg|thumb|A diagram demonstrating a check valve.]] Following an investigation, SpaceX stated that the explosion was the result of a faulty valve. During a nominal ignition sequence, valves keeping helium inside COPVs (Composite Overwrapped Pressure Vessels) are opened, causing the helium to flow through one-way check valves into the propellant tanks, pushing the fuel into the combustion chamber.<ref>{{cite web|last=Cannon |first=James L. |date=2010-10-05 |title=Liquid Propulsion: Propellant Feed System Design |url=https://ntrs.nasa.gov/api/citations/20100035254/downloads/20100035254.pdf |url-status=live |archive-url=https://web.archive.org/web/20240930204424/https://ntrs.nasa.gov/api/citations/20100035254/downloads/20100035254.pdf |archive-date=2024-09-30 |access-date=2024-10-02 |website=NASA Technical Reports Server}}</ref> {{See also|Pressure-fed engine}} In this incident, however, the one-way oxidizer valve had allowed nitrogen tetroxide (NTO) to leak back through the helium tube.<ref>{{Cite news|last=Harwood |first=William |date=2019-07-15 |title=SpaceX: Explosion that destroyed Crew Dragon spacecraft in April was caused by leaking valve - CBS News |url=https://www.cbsnews.com/news/spacex-explosion-destroyed-crew-dragon-spacecraft-blamed-on-leaking-valve/ |url-status=live |archive-url=https://web.archive.org/web/20240225135153/https://www.cbsnews.com/news/spacex-explosion-destroyed-crew-dragon-spacecraft-blamed-on-leaking-valve/ |archive-date=2024-02-25 |access-date=2024-10-02 |website=cbsnews.com |language=en-US}}</ref> When the helium valve was opened, the "blobs" of NTO inside the helium line were accelerated at high speeds, slamming into and nearly instantaneously destroying the one-way oxidizer valve. The internal titanium components of the destroyed valve were then exposed to the NTO, resulting in combustion and the loss of the vehicle.<ref>{{Cite web |last=SpaceX |date=2019-07-15 |title=UPDATE: IN-FLIGHT ABORT STATIC FIRE TEST ANOMALY INVESTIGATION {{!}} SpaceX |url=https://www.spacex.com/news/2019/07/15/update-flight-abort-static-fire-anomaly-investigation |url-status=live |archive-url=https://web.archive.org/web/20190715213628/https://www.spacex.com/news/2019/07/15/update-flight-abort-static-fire-anomaly-investigation |archive-date=2019-07-15 |access-date=2024-10-02 |website=SpaceX.com}}</ref><ref>{{Cite news|author1=Foust |first=Jeff |date=2019-07-16 |title=SpaceX Says Faulty Valve Led to Crew Dragon Test Accident |url=https://www.space.com/spacex-crew-dragon-explosion-faulty-valve.html |url-status=live |archive-url=https://web.archive.org/web/20240304011335/https://www.space.com/spacex-crew-dragon-explosion-faulty-valve.html |archive-date=2024-03-04 |access-date=2024-10-02 |website=Space.com |language=en}}</ref>
=== In-Flight Abort Test === thumb|356x356px|A video of the in-flight abort test. {{Main articles|Crew Dragon In-Flight Abort Test}}
On 19 January 2020, SpaceX conducted a test of Crew Dragon's launch abort system.<ref>{{Cite news|author1=Thompson |first=Amy |date=2020-01-19 |title=SpaceX aces Crew Dragon launch abort test, destroys rocket on purpose |url=https://www.space.com/spacex-crew-dragon-launch-abort-test-success.html |url-status=live |archive-url=https://web.archive.org/web/20240728021045/https://www.space.com/spacex-crew-dragon-launch-abort-test-success.html |archive-date=2024-07-28 |access-date=2024-10-02 |website=Space.com |language=en}}</ref>
After a successful liftoff, the launch abort sequence was initiated 1 minute and 26 seconds into flight. Crew Dragon C205 successfully separated with the Falcon 9 rocket, with the rocket breaking up seconds later under the intense aerodynamic forces of max-q.<ref>{{Cite web |last=ScienceAlert |date=2020-01-19 |title=With a Spectacular Explosion, SpaceX's Crew Dragon Just Passed a Crucial Safety Test |url=https://www.sciencealert.com/spacex-s-crew-dragon-just-passed-a-crucial-safety-test-with-a-spectacular-launch |url-status=live |archive-url=https://web.archive.org/web/20220813041223/https://www.sciencealert.com/spacex-s-crew-dragon-just-passed-a-crucial-safety-test-with-a-spectacular-launch |archive-date=2022-08-13 |access-date=2024-10-02 |website=ScienceAlert |language=en-US}}</ref>
After separating the trunk, Crew Dragon reached an apogee of 42 kilometers before splashing down in the Atlantic Ocean.<ref>{{Cite web |author1=Malik |first=Tariq |date=2020-01-19 |title=How SpaceX's Crew Dragon launch abort test today works in 10 not-so-easy steps |url=https://www.space.com/spacex-crew-dragon-in-flight-abort-test-step-by-step.html |url-status=live |archive-url=https://web.archive.org/web/20240616155331/https://www.space.com/spacex-crew-dragon-in-flight-abort-test-step-by-step.html |archive-date=2024-06-16 |access-date=2024-10-02 |website=Space.com |language=en}}</ref><ref>{{Cite web |last=Atkinson |first=Ian |date=2020-01-17 |title=SpaceX conducts successful Crew Dragon In-Flight Abort Test |url=https://www.nasaspaceflight.com/2020/01/spacex-crew-dragon-in-flight-abort-test/ |url-status=live |archive-url=https://web.archive.org/web/20240725001143/https://www.nasaspaceflight.com/2020/01/spacex-crew-dragon-in-flight-abort-test/ |archive-date=2024-07-25 |access-date=2024-10-02 |website=NASASpaceFlight.com |language=en-US}}</ref>
== Abort modes == The Crew Dragon has multiple abort modes for different phases of flight, each with its own landing zones and procedures. As the flight progresses, SpaceX mission control calls out switches between abort modes.
For typical launches, recovery zones are placed along the 51.64-degree inclination<ref>{{Cite web |last=NASA |title=International Space Station - NASA |url=https://www.nasa.gov/reference/international-space-station/ |url-status=live |archive-url=https://web.archive.org/web/20241001193821/https://www.nasa.gov/reference/international-space-station/ |archive-date=2024-10-01 |access-date=2024-10-02 |website=NASA.gov |language=en-US}}</ref> of the ISS, and can be targeted with higher levels of precision than spacecraft such as Orion<ref>{{cite web|last=Jones |first=Daniel L. |date=2015-03-03 |title=Orion Launch Abort System (LAS) {{!}} Propulsion on Pad Abort 1 (PA-1) |url=https://ntrs.nasa.gov/api/citations/20150002697/downloads/20150002697.pdf |url-status=live |archive-url=https://web.archive.org/web/20240930153704/https://ntrs.nasa.gov/api/citations/20150002697/downloads/20150002697.pdf |archive-date=2024-09-30 |access-date=2024-10-02 |website=NASA Technical Reports Server}}</ref> and Shenzhou due to the throttling abilities of the SuperDraco engines. The recovery areas for a 2a type abort are along the East Coast of the United States and The Maritimes on Canada's Atlantic coast, with a 2b abort landing the Crew Dragon capsule near Nova Scotia and the 2c and 2d abort modes resulting in a landing in Western Ireland.<ref name=":1">{{Cite web |last=Gebhardt |first=Chris |date=2020-05-21 |title=Examining Crew Dragon's launch abort modes and splashdown locations |url=https://www.nasaspaceflight.com/2020/05/examining-crew-dragons-launch-abort-modes-and-splashdown-locations/ |url-status=live |archive-url=https://web.archive.org/web/20240926005947/https://www.nasaspaceflight.com/2020/05/examining-crew-dragons-launch-abort-modes-and-splashdown-locations/ |archive-date=2024-09-26 |access-date=2024-10-02 |website=NASASpaceFlight.com |language=en-US}}</ref> 1a and 1b aborts result in landings near the American East Coast. {| class="wikitable" |+ !Time !Phase !Recovery zone<ref name=":1" /><ref name="Launch Day Timeline">{{Cite web |last=DeSisto |first=Austin |date=2020-05-24 |title=Crew Dragon Launch Day Timeline: From Suit Up to Docking with the ISS |url=https://everydayastronaut.com/crew-dragon-timeline/ |url-status=live |archive-url=https://web.archive.org/web/20240926003159/https://everydayastronaut.com/crew-dragon-timeline/ |archive-date=2024-09-26 |access-date=2024-10-02 |website=Everyday Astronaut |language=en-US}}</ref> |- |''T'' − 37 minutes |Pad abort |Launch abort armed; recovery zone in Florida coast |- |''T'' + 00 minutes 00 seconds |Stage 1a |Recovery zones from Florida coast to North Carolina |- |''T'' + 01 minutes 15 seconds |Stage 1b |Recovery zones along Virginia coast |- |''T'' + 02 minutes 32 seconds |Stage 2a |Stage separation; recovery zones along North American east coast |- |''T'' + 08 minutes 05 seconds |Stage 2b |Retrograde burn to land near Nova Scotia |- |''T'' + 08 minutes 28 seconds |Stage 2c |Prograde burn to land west of Ireland |- |''T'' + 08 minutes 38 seconds |Stage 2d |Retrograde burn to land west of Ireland |- |''T'' + 08 minutes 44 seconds |Stage 2e |Uses SuperDracos and Dracos to abort to orbit |}
== See also ==
* Crew Dragon in-flight abort test, a post-launch abort test of the SpaceX Crew Dragon spacecraft * Crew Dragon pad abort test, a test of Dragon's abort system while on the launch pad * SpaceX Dragon, a family of SpaceX spacecraft
== References ==
{{reflist}} Category:Crew Dragon Category:Spacecraft components