Editing STS-1 (section)

=== Mission anomalies ===
[[File:EM-0084-01.ogg|thumb|upright=1.0|right|STS-1 touches down at [[Edwards Air Force Base]],]]
[[File:Columbia STS-1 training.jpg|thumb|upright=1.0|right|STS-1 crew in Space Shuttle ''Columbia''{{'}}s cabin. This is a view of training in 1980 in the [[Orbiter Processing Facility]].]]

STS-1 was the first orbital test flight of what NASA claims was, at the time, the most complex flying machine ever built.<ref name="NASAOkolski">{{cite web |url=https://history.nasa.gov/sts25th/tech.html|publisher=NASA|title=Shuttle Technology|first=Gabriel|last=Okolski}}</ref> Roughly 70 anomalies were observed during and after the flight, owing to the many components and systems that could not otherwise be adequately tested. These included:

* Similar to the [[Apollo 4|first Saturn V launch]] in 1967, engineers underestimated the amount of noise and vibration produced by the Space Shuttle.<ref name=drop/> Shock waves from the SRB thrust were deflected up into the orbiter's tail section, which flexed the wing flaps and bent several fuel tank supports; Columbia could have had trouble landing if the flaps had been damaged.<ref>{{cite news |title=Cushioning System Tested for Space Shuttle |url=https://www.nytimes.com/1981/09/18/us/cushioning-system-tested-for-space-shuttle.html |work=The New York Times |issue=45075 |volume= 131|date=18 September 1981 |archive-url= https://web.archive.org/web/20180125053119/https://www.nytimes.com/1981/09/18/us/cushioning-system-tested-for-space-shuttle.html |archive-date=25 January 2018}}</ref> An improved [[sound suppression system]] was later installed in LC-39A to damp vibrations.<ref name=drop>{{cite web |url=http://quest.nasa.gov/qna/questions/FAQ_Shuttle_Launch.htm|title=FAQ: Why do you drop water under the shuttle as the engines start?|publisher=NASA|date=January 5, 1999|url-status=dead|archive-url=https://web.archive.org/web/20130515113630/http://quest.nasa.gov/qna/questions/FAQ_Shuttle_Launch.htm|archive-date=May 15, 2013}} {{PD-notice}}</ref>
* Pilot Crippen reported that, throughout the first stage of the launch up to SRB separation, he saw "white stuff" coming off the External Tank and splattering the windows, which was probably the white paint covering the External Tank's thermal foam.<ref name="STS-1 Technical Crew Debriefing page 4-4"/>
* The astronauts' on-orbit visual inspection showed significant damage to the thermal protection tiles on the [[Orbital Maneuvering System|OMS/RCS]] pods at the orbiter's aft end, and John Young reported that two tiles on the nose looked like someone had taken "big bites out of them".<ref name="STS-1 Technical Crew Debriefing page 4-4">STS-1 Technical Crew Debriefing, page 4-4</ref> The [[United States Air Force|U.S. Air Force]] also photographed the orbiter's tiles using a secret KH-11 KENNEN reconnaissance satellite controlled by [[Blue Cube]]. Only the prime and backup crews and a few other NASA employees were aware of this. Young and Crippen were instructed to perform maneuvers to align ''Columbia'' so that the KH-11 could photograph it; because of the preplanned required trajectory, the launch window was far narrower than the publicized six hours.<ref name="white20170412">{{Cite magazine |last=White |first=Rowland |date=2017-04-12 |title=The Spysat and the Shuttle |url=https://www.smithsonianmag.com/air-space-magazine/spysat-and-shuttle-180962872/ |access-date=2024-12-02 |magazine=Air & Space |language=en}}</ref> Images obtained confirmed that damage to ''Columbia'' was not serious.<ref>{{cite web|url=http://www.thespacereview.com/article/3219/1|title=The Space Review: Passing in silence, passing in shadows|website=thespacereview.com}}</ref><ref name="king19810413">{{cite news |url=https://news.google.com/newspapers?id=4rRkAAAAIBAJ&pg=5544%2C1256886|title=NASA says missing tiles no threat to shuttle|newspaper=The Madison Courier|date=April 13, 1981|agency=Associated Press|access-date=January 22, 2013|author=King, James R.}}</ref> Post-flight inspection of ''Columbia'' confirmed that approximately 16 undensified tiles near the OMS pod had been lost during ascent.<ref name=STS-1-AR>{{cite news|url=http://www.jsc.nasa.gov/news/columbia/anomaly/STS1.pdf|title=STS-1 Anomaly Report|date=February 27, 2003|publisher=NASA|access-date=July 14, 2006|archive-url=https://web.archive.org/web/20061007035617/http://www.jsc.nasa.gov/news/columbia/anomaly/STS1.pdf|archive-date=October 7, 2006|url-status=dead}} {{PD-notice}}</ref>
* ''Columbia'''s aerodynamics at high [[Mach number]]s during reentry were found to differ significantly in some respects from those estimated in pre-flight testing. A misprediction of the [[Atmospheric reentry#Real (equilibrium) gas model|location of the center of pressure]] (due to using an [[ideal gas]] model instead of a [[real gas]] model) caused the computer to have to extend the body flap by sixteen degrees rather than the expected eight or nine. The first roll maneuver resulted in lateral and directional oscillations during which side slip angles of up to 4° were reached, twice as high as predicted.<ref name=STS-1-AR/><ref>{{cite web|url=https://docs.google.com/viewer?a=v&q=cache:4E51uFAP7IQJ:ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19940006365_1994006365.pdf+&hl=en&gl=us&pid=bl&srcid=ADGEESjwyAKkS0Wa0VG5mRVHma6eLMmiDlY0K-rMbA2v4A9nbj4mp-3H5Sulcz4xbKV7nHIurn6w8bqFjEgJpKcRkTUZeJP7GAmPB36OxGpaJCNtFDmDaRwsgtmH5z1XpHp6OGHFGuco&sig=AHIEtbTZaunOq2H9MFtGoFCgmN6sMxN0Jw|title=Space Shuttle Hypersonic Aerodynamic and Aerothermodynamic Flight Research and the Comparison to Ground Test Results|first1=Kenneth|last1=Iliff|first2=Mary|last2=Shafer|pages=5–6|date=June 1993|access-date=February 16, 2013|publisher=Google Docs}} {{PD-notice}}</ref> Analysis attributed the cause to unexpectedly large rolling moments due to yaw RCS jet firings. During the early stages of entry, orbiter roll control is achieved as a result of [[Slip (aerodynamics)|sideslip]] modulation.
* The orbiter's heat shield was damaged when an [[overpressure]] wave from the [[Space Shuttle Solid Rocket Booster|solid rocket booster]] caused a forward RCS oxidizer strut to fail.<ref name=STS-1-AR/>
* The same overpressure wave also forced the [[orbiter body flap]] – an extension on the orbiter's underbelly that helps to control pitch during reentry – into an angle well beyond the point where cracking or rupture of its [[hydraulic]] system would have been expected. Such damage would have made a controlled descent impossible, with John Young later admitting that had the crew known about this, they would have flown the shuttle up to a safe altitude and ejected, causing ''Columbia'' to be lost on the first flight. Young had reservations about ejection as a safe abort mode due to the fact that the SRBs were firing throughout the ejection window, but he justified taking this risk because, in his view, an inoperative body flap would have made landing and descent "extremely difficult if not impossible."<ref name="boyle">{{cite news|author=Boyle, Alan (quoting a recollection of James Oberg)|title=Cosmic Log: April 8-14, 2006|url=https://www.nbcnews.com/id/wbna12243173|access-date=January 8, 2018|agency=NBC News|quote=After the flight, mission commander John Young was shown those videos. His reaction was severe. 'Had I known the body flap had been deflected so far off position', he told associates, 'I'd have concluded the hydraulic lines had been ruptured and the system was inoperative'. Without a working body flap, a controlled descent and landing would have been extremely difficult if not impossible. The pitch control thrusters might or might not have been enough to provide control. The shuttle might have tumbled out of control and disintegrated at very high speed and altitude ... 'I'd have ridden the vehicle up to a safe altitude', he later stated, 'and while still in the ejection envelope [the range of speed and altitude for safely firing the ejection seats] I'd have pulled the ring'.}}</ref><ref>{{cite web|url=http://www.collectspace.com/news/news-041006a.html|title=L+25 Years: STS-1's Young and Crippen |publisher=collectSPACE}}</ref>
* The strike plate next to the forward latch of ''Columbia''{{'}}s [[external tank]] door was melted and distorted due to excess heat exposure during reentry. This heat was attributed to an improperly installed tile adjacent to the plate.<ref name=STS-1-AR/>
* During remarks at a 2003 gathering, John Young stated that a protruding tile gap filler ducted hot gas into the right main landing gear well, which caused significant damage, including the buckling of the landing gear door.<ref>{{cite web |author=Foust |first=Jeff |date=April 14, 2003 |title=John Young's shuttle secret |url=http://www.thespacereview.com/article/15/1 |access-date=August 22, 2010 |publisher=Space Review}}</ref> He said that neither he nor Crippen were told about this incident and he was not aware that it had happened until reading the postflight mission report for STS-1, also adding that the gas leak was noted in the report, but not the buckling of the landing door. (The buckling of the door is in fact in the anomaly report, anomaly STS-1-V-49).<ref name=STS-1-AR/>

Despite these problems, the STS-1 mission was completed successfully, and in most respects ''Columbia'' performed optimally. After some modifications to the Shuttle and to the launch and reentry procedures,<ref>{{cite book |author=A. |first=Cohen |title=STS-1 Orbiter Final Mission Report |date=1981 |publisher=NASA JSC Mission Evaluation Team |pages=152–237}} {{PD-notice}}</ref> ''Columbia'' flew the next four Shuttle missions.