View source for Launch vehicle system tests

{{Short description|Preparation procedures for verifying carrier rocket performance}}{{Globalize|date=July 2021}}[[File:COTS 2 Falcon 9 - WDR.1.cropped.jpg|A [[Falcon 9]] rocket during a Wet Dress Rehearsal on 1 March 2012|right|thumb]]
'''Launch vehicle  system tests''' assess the readiness of a launch system to safely reach orbit. Launch vehicles undergo [[system testing|system tests]] before they launch. Wet dress rehearsals (WDR) and more extensive static fire tests prepare fully assembled [[launch vehicle|launch vehicles]] and their associated [[ground support equipment]] (GSE) prior to <!-- "spacecraft integration and" -- wdr may or may not be done with the spacecraft/payload already integrated to the launch vehicle; they have been, and still continue to be, done both ways.  No source here showing it to be only the one way. -->launch. The spacecraft/payload may or may not be attached to the launch vehicle during the WDR or static fire, but sufficient elements of the rocket and all relevant ground support equipment are in place to help verify that the rocket is ready for flight.
Propellant load tests and static fire tests may also be done on [[test article (aerospace)|prototype]] rocket stages, in which case no fully assembled launch vehicle is involved, as is the case of the SpaceX Starship stages, the booster [[SpaceX Super Heavy|Super Heavy]] and the second stage [[SpaceX Starship (spacecraft)|Starship]].<!-- many examples exist, but the test of just the Starship second stage (aka [[Starship (spacecraft)]]) and just the "Super Heavy" booster of the SpaceX Starship system have both seen static fire tests -->
==Wet dress rehearsal ==
A wet dress rehearsal<ref>{{Cite web |last=Harbaugh |first=Jennifer |date=December 4, 2020 |title=NASA ‘Go’ for Green Run Wet Dress Rehearsal – Artemis |url=https://blogs.nasa.gov/artemis/2020/12/04/nasa-go-for-green-run-wet-dress-rehearsal/ |url-status=live |archive-url=https://web.archive.org/web/20210715163642/https://blogs.nasa.gov/artemis/2020/12/04/nasa-go-for-green-run-wet-dress-rehearsal/ |archive-date=2021-07-15 |access-date=2021-07-15 |website=[[NASA]] |language=en-US}}</ref> is called "wet" because the liquid [[rocket propellant|propellant]] components (such as [[liquid oxygen]], [[liquid hydrogen]], etc.) are loaded into the rocket during the test. In a pure wet dress rehearsal the rocket engines are not ignited. Wet dress rehearsals may be used on production launch vehicles before each flight<ref>{{cite web|title=GPS IIF-2 Wet Dress Rehearsal – SpacePod 2011.06.09|url=http://www.spacevidcast.com/2011/06/09/gps-iif-2-wet-dress-rehearsal-spacepod-2011-06-09/|accessdate=6 July 2011|archive-date=2011-07-03|archive-url=https://web.archive.org/web/20110703162449/http://www.spacevidcast.com/2011/06/09/gps-iif-2-wet-dress-rehearsal-spacepod-2011-06-09/|url-status=live}}</ref> or on prototypes under [[new product development|development]].<ref name=trati20200512>{{cite news |url=https://www.teslarati.com/spacex-starship-first-triple-raptor-prototype/ |title=SpaceX’s first high-flying, triple-Raptor Starship is almost finished |last=Ralph |first=Eric |work=Teslarati |date=12 May 2020 |access-date=1 October 2021 |archive-date=19 January 2021 |archive-url=https://web.archive.org/web/20210119114250/https://www.teslarati.com/spacex-starship-first-triple-raptor-prototype/ |url-status=live }}</ref>
== Static fire ==
A static fire test includes a wet dress rehearsal and adds the step of firing the engines at full thrust.<ref name=trati20200512/>  The engine(s) are fired for a few seconds while the [[launch vehicle]] is held firmly attached to the [[launch mount]]. This tests engine startup while measuring pressure, temperature and propellant-flow gradients, and can be performed with or without payload.  The data gathered in such tests may be used to form a unique (rocket- and engine-specific) set of criteria as part of the [[Launch status check|go/no-go]] [[decision tree]] in the launch software that is used on launch day.  Some static fire tests have fired the engines for twelve<ref>{{cite news |url=https://www.nasaspaceflight.com/2018/01/spacex-static-fire-falcon-heavy-1/ |title=Falcon Heavy comes to life as SpaceX conduct Static Fire test |author=Chris Gebhardt |date=24 January 2018 |publisher=NASASpaceFlight.com |access-date=12 January 2018 |archive-date=10 January 2018 |archive-url=https://web.archive.org/web/20180110050733/https://www.nasaspaceflight.com/2018/01/spacex-static-fire-falcon-heavy-1/ |url-status=live }}</ref> and even twenty seconds,<ref>{{Cite web|url=https://www.americaspace.com/2015/09/19/firing-up-the-shuttle-looking-back-at-the-flight-readiness-firings-part-1/|last=Evans|first=Ben|date=19 September 2015|title=Firing Up the Shuttle: Looking Back at the Flight Readiness Firings|publisher=AmericaSpace|access-date=10 July 2021|archive-date=10 July 2021|archive-url=https://web.archive.org/web/20210710074524/https://www.americaspace.com/2015/09/19/firing-up-the-shuttle-looking-back-at-the-flight-readiness-firings-part-1/|url-status=live}}</ref> although shorter firings are more typical.<ref name=nsf20160112>{{cite news |url=http://www.nasaspaceflight.com/2016/01/spacex-preparing-west-coast-jason-3-launch-with-last-falcon-9-v1-1/ |title=SpaceX Falcon 9 v1.1 conducts static fire test ahead of Jason-3 mission |author=Chris Gebhardt |date=12 January 2016<!-- article date still shows as 8 Jan, but article was updated in early am UTC on 12 Jan following successful evening local California time static fire test --> |publisher=NASASpaceFlight.com |access-date=12 January 2016 |archive-date=7 June 2017 |archive-url=https://web.archive.org/web/20170607080444/https://www.nasaspaceflight.com/2016/01/spacex-preparing-west-coast-jason-3-launch-with-last-falcon-9-v1-1/ |url-status=live }}</ref><ref>{{cite web|url=https://www.nasaspaceflight.com/2017/03/ses-10-static-fire-spacex-first-core-re-flight/|title=SES-10 F9 static fire – SpaceX for history books & first core stage re-flight – NASASpaceFlight.com|website=www.nasaspaceflight.com|access-date=2017-03-30|archive-date=2017-03-28|archive-url=https://web.archive.org/web/20170328064007/https://www.nasaspaceflight.com/2017/03/ses-10-static-fire-spacex-first-core-re-flight/|url-status=live}}</ref>
== Use ==
Many [[launch service provider]]s do not regularly perform wet dress rehearsals on new launch vehicles; {{asof|2018|lc=y}} some regularly perform wet dress rehearsals or even full static fire tests on the [[launch mount]]. For example, [[SpaceX]] typically performs a full static fire on every new booster and also on each [[SpaceX reusable rocket|reflown booster]] before every launch, sometimes more than once. In January 2018, SpaceX did two wet dress rehearsals on the [[Zuma (satellite)|Zuma]] [[Falcon 9]] mission, and conducted multiple wet dress rehearsals on the [[Falcon Heavy]] launch vehicle which had its [[maiden flight|maiden launch]] on 6 February 2018. Both were explicitly booked as wet dress rehearsals, but with the option to proceed to a static fire test. The second wet dress rehearsal on 24 January 2018 led to a full 12-second static fire test of the 27 engines of the Falcon Heavy — a much longer static fire test than the typical 3–7 second duration tests SpaceX uses for the Falcon 9.<ref name=nsf20180109>{{cite news|last=Gebhardt|first=Chris|url=https://www.nasaspaceflight.com/2018/01/spacex-static-fire-falcon-heavy-1/|title=Falcon Heavy comes to life as SpaceX conduct Static Fire test|work=[[NASASpaceFlight.com]]|date=2018-01-24|access-date=2018-01-12|archive-date=2018-01-10|archive-url=https://web.archive.org/web/20180110050733/https://www.nasaspaceflight.com/2018/01/spacex-static-fire-falcon-heavy-1/|url-status=live}}</ref><!-- nasaspaceflight.com often keep the same URL, and update their articles rather substantially; so this is the new title with new prose that followed the successful static fire test; if want the earlier title and article prose the preceded and then followed the first wet dress rehearsal of the Falcon Heavy, would have to go the internet archive for this URL -->
== Anomalies ==
Wet rehearsal and static fire tests can fail catastrophically, such as that which resulted in a pad explosion of a [[SpaceX]] [[Falcon 9]] on September 1, 2016.<ref name=lat20160909>[http://www.latimes.com/business/la-fi-spacex-investigation-20160909-snap-story.html Elon Musk: Launch pad explosion is 'most difficult and complex' failure in SpaceX's 14 years] {{Webarchive|url=https://web.archive.org/web/20170216212623/http://www.latimes.com/business/la-fi-spacex-investigation-20160909-snap-story.html |date=2017-02-16 }} LA Times September 9, 2016</ref> The failure resulted from a major breach of the cryogenic helium system of the [[second stage]] during propellant-loading operations. The explosion destroyed the [[Falcon 9|rocket]] and its payload - the [[AMOS-6]] satellite. Furthermore, due to extensive fire, the [[Cape Canaveral Air Force Station Space Launch Complex 40|SLC-40]] [[launch pad]] was heavily damaged and had to be rebuilt.<ref name=tc20160923>{{Cite web|url=https://techcrunch.com/2016/09/23/spacex-investigation-suggests-helium-breach-caused-its-falcon-9-explosion/|title=SpaceX investigation suggests helium breach caused its Falcon 9 explosion|last=Etherington|first=Darrell|website=TechCrunch|access-date=2016-09-26|archive-date=2016-09-26|archive-url=https://web.archive.org/web/20160926194820/https://techcrunch.com/2016/09/23/spacex-investigation-suggests-helium-breach-caused-its-falcon-9-explosion/|url-status=live}}</ref><ref name=bb20160923>{{Cite news|url=https://www.bloomberg.com/news/articles/2016-09-23/spacex-says-it-will-return-to-rocket-flight-as-early-as-november|title=SpaceX Sees Clue to Rocket Blast in Super-Chilled Helium Breach|last=Hull|first=Dana|date=2016-09-23|newspaper=Bloomberg.com|access-date=2016-09-26|archive-date=2016-09-26|archive-url=https://web.archive.org/web/20160926075250/http://www.bloomberg.com/news/articles/2016-09-23/spacex-says-it-will-return-to-rocket-flight-as-early-as-november|url-status=live}}</ref>
Static fire test failures have resulted in the unintentional launch of the test vehicle. On June 6th, 1952, [[Viking (rocket)#Second_model_RTV-N-12a_(Vikings_8-12)|Viking 8]] broke loose of its moorings during a static fire test. After 55 seconds of flight, a command was sent to cut propulsion, and the rocket crashed  {{convert|4|mi|0}} or {{convert|5|mi|0}} downrange.<ref>{{cite book|author=Milton W. Rosen|title=The Viking Rocket Story|publisher=Harper & Brothers|location=New York|date=1955|oclc=317524549}}</ref>{{rp|172–181}} On June 30th, 2024, during a static fire test of the first stage of the [[Space Pioneer]] [[Tianlong-3]], a structural failure between the rocket and test stand resulted in an unintentional launch.<ref>{{cite tweet |author=Andrew Jones |user=AJ_FI |number=1807339807640518690 |title=Wow. This is apparently what was supposed to be a STATIC FIRE TEST today of a Tianlong-3 first stage by China's Space Pioneer. That's catastrophic, not static. Firm was targeting an orbital launch in the coming months. https://m.weibo.cn/detail/5050998629862652 |date=30 June 2024}}</ref><ref>{{cite web |title=关于天龙三号大型液体运载火箭一子级动力系统试车的情况说明 |url=https://mp.weixin.qq.com/s/6K2mdDWviOlk30oU-JH90Q |access-date=30 June 2024 |archive-url= https://web.archive.org/web/20240630112213/https://mp.weixin.qq.com/s/6K2mdDWviOlk30oU-JH90Q |archive-date=2024-06-30 |language=zh-cn}}</ref> The rocket landed and exploded in the nearby mountains.
== References ==
{{Portal|Spaceflight}}
{{Reflist|30em}}
== External links ==
* [https://www.aiaa.org/uploadedFiles/Events/Conferences/2012_Conferences/2012-Complex-Aerospace-Systems-Exchange-Event/Detailed_Program/CASE2012_2-4_Muratore_presentation.pdf SpaceX Systems Engineering presentation from CASE 2012], 28 September 2012. <!-- time context is after only the first three Falcon 9 v1.0 flights had occurred; SpaceX was still, at that time, flying rather infrequently yet had spent a great deal of time in all five levels of system engineering integration of hardware and software for verification and validation testing--> Includes description of SpaceX approach to fifth-level hardware-software integration testing during their wet dress rehearsal and/or static fire testing.
[[Category:Aerospace system testing]]
[[Category:Spaceflight concepts]]
[[Category:Tests]]