Editing Space Shuttle Columbia disaster (section)

=== Reentry ===
''Columbia'' was scheduled to reenter the atmosphere and land on February 1, 2003. At 3:30{{spaces}}am EST the Entry [[flight controller|Flight Control Team]] started its shift at the [[Christopher C. Kraft Jr. Mission Control Center|Mission Control Center]].{{r|caib_report}}{{Reference page|page=38}} On board the orbiter, the crew stowed loose items and prepared their equipment for reentry.<ref name="survival_report">{{cite web
  | title = Columbia Crew Survival Investigation Report
  | publisher = NASA
  | date = 2008
  | url = https://www.nasa.gov/pdf/298870main_SP-2008-565.pdf
  | id = SP-2008-565
  | access-date = February 11, 2022
| archive-date = July 25, 2021
| archive-url = https://web.archive.org/web/20210725011744/https://www.nasa.gov/pdf/298870main_SP-2008-565.pdf
  | url-status = live
  }}</ref>{{Reference page|page=1.5}}

At 45 minutes before the deorbit burn, Husband and McCool began working through the entry checklist.{{r|survival_report}}{{Reference page|page=1.6}} At 8:10{{spaces}}am the [[Flight controller#Spacecraft communicator (CAPCOM)|Capsule Communicator (CAPCOM)]], [[Charles O. Hobaugh|Charlie Hobaugh]],<ref name="latimes_capcom">{{cite web
  | last = Hotz
  | first = Robert Lee
  | title = Decoding Columbia: A detective story
  | work = [[The Los Angeles Times]]
  | date = January 31, 2013
| url = https://www.latimes.com/nation/la-sci-shuttle21dec21-1-story.html
  | accessdate = July 24, 2023
| archive-date = June 4, 2023
| archive-url = https://web.archive.org/web/20230604152132/https://www.latimes.com/nation/la-sci-shuttle21dec21-1-story.html
  | url-status = live
  }}</ref> informed the crew that they were approved to conduct the deorbit burn. At 8:15:30{{spaces}}the crew successfully executed the deorbit burn, which lasted 2{{spaces}}minutes and 38{{spaces}}seconds. At 8:44:09{{spaces}}''Columbia'' reentered the atmosphere at an altitude of {{convert|400000|ft|km}}, a point named entry interface. The damage to the TPS on the orbiter's left wing allowed hot air to enter and begin melting the aluminum structure.{{r|caib_report|p=9}} Four and a half minutes after entry interface, a sensor began recording greater-than-normal amounts of strain on the left wing; the sensor's data was recorded to internal storage and not transmitted to the crew or ground controllers.{{r|caib_report|p=38}} The orbiter began to turn ([[Aircraft principal axes#Vertical axis (yaw)|yaw]]) to the left as a result of the increased drag on the left wing, but this was not noticed by the crew or mission control because of corrections from the orbiter's flight control system.{{r|survival_report}}{{Reference page|page=1.8}} This was followed by sensors in the left wheel well reporting a rise in temperature.{{r|survival_report}}{{Reference page|page=1.10}}
[[File:STS-107 Columbia entry imaged from ground.jpg|thumb|''Columbia'' at about 08:57. Debris is visible coming from the left wing (bottom). The image was taken at [[Starfire Optical Range]] at [[Kirtland Air Force Base]].|alt=Fuzzy black-and-white photo of the orbiter during reentry]]

At 8:53:46 am, ''Columbia'' crossed over the [[California]] coast; it was traveling at Mach{{spaces}}23 at an altitude of {{convert|231600|ft|km}}, and the temperature of its wings' leading edges was estimated to be {{convert|2800|F|C}}.{{r|caib_report}}{{Reference page|page=38}} Soon after it entered California airspace, the orbiter shed several pieces of debris, events observed on the ground as sudden increases in brightness of the air around the orbiter. The [[List_of_NASA's_flight_control_positions#MMACS|MMACS]] officer reported that the hydraulic sensors in the left wing had readings below the sensors' minimum detection thresholds at 8:54:24{{spaces}}am. ''Columbia'' continued its reentry and traveled over [[Utah]], [[Arizona]], [[New Mexico]], and [[Texas]], where observers would report seeing signs of debris being shed.{{r|caib_report}}{{Reference page|page=39}}

At 8:58:03, the orbiter's [[Flight control surfaces#Rudder and aileron trim|aileron trim]] changed from the predicted values because of the increasing drag caused by the damage to the left wing. At 8:58:21, the orbiter shed a TPS tile that would later land in [[Littlefield, Texas]]; it would become the westernmost piece of recovered debris.{{r|survival_report}}{{Reference page|page=1.12}} The crew first received an indication of a problem at 8:58:39, when the Backup Flight Software monitor began displaying fault messages for a loss of pressure in the tires of the left landing gear. The pilot and commander then received indications that the status of the left landing gear was unknown, as different sensors reported the gear was down and locked or in the stowed position.{{r|survival_report}}{{Reference page|page=1.13}} The drag of the left wing continued to yaw the orbiter to the left until it could no longer be corrected using aileron trim. The orbiter's [[Space Shuttle orbiter#Attitude control system|Reaction Control System]] (RCS) thrusters began firing continuously to correct its orientation.{{r|survival_report}}{{Reference page|page=1.14}}

The loss of signal (LOS) from ''Columbia'' occurred at 8:59:32. Mission control stopped receiving information from the orbiter at this time, and Husband's last radio call of "Roger, uh{{spaces}}..." was cut off mid-transmission.{{r|caib_report}}{{Reference page|page=39}}{{r|survival_report}}{{Reference page|page=1.14}} One of the channels in the flight control system was bypassed as the result of a failed wire, and a Master Alarm began sounding on the flight deck.{{r|survival_report}}{{Reference page|page=1.15}} Loss of control of the orbiter is estimated to have begun several seconds later with a loss of hydraulic pressure and an uncontrolled [[Aircraft principal axes#Transverse axis (pitch)|pitch]]-up maneuver.{{r|survival_report}}{{Reference page|page=1.16}} The orbiter began flying along a [[ballistic trajectory]], which was significantly steeper and had more drag than the previous gliding trajectory.{{r|survival_report}}{{Reference page|page=1.17}} The orbiter, while still traveling faster than Mach 15, entered into a [[Flat spin (aviation)|flat spin]] of 30° to 40° per second. The acceleration that the crew was experiencing increased from approximately 0.8 [[g-force|g]] to 3{{spaces}}g, which would have likely caused dizziness and disorientation, but not incapacitation.{{r|survival_report}}{{Reference page|page=1.18}} The autopilot was switched to manual control and reset to automatic mode at 9:00:03; this would have required the input of either Husband or McCool, indicating that they were still conscious and able to perform functions at the time. All hydraulic pressure was lost, and McCool's final switch configurations indicate that he had tried to restore the hydraulic systems at some time after 9:00:05.{{r|survival_report}}{{Reference page|page=1.20}}

[[File:ColumbiaFLIR2003.gif|thumb|Breakup of the Space Shuttle Columbia as seen from an Apache helicopter FLIR camera at Fort Hood, Texas<ref name="aviationist-20140201">{{Cite news |last=Cenciotti |first=David |date=February 1, 2014 |title=Space Shuttle Columbia Disaster as seen through AH-64 Apache camera |work=The Aviationist |url=https://theaviationist.com/2014/02/01/sts-107-disaster-video/ |url-status=live |archive-url=https://web.archive.org/web/20230331125749/https://theaviationist.com/2014/02/01/sts-107-disaster-video/ |archive-date=March 31, 2023 }}</ref>]]
At 9:00:18, the orbiter began a catastrophic breakup, and all on-board data recording soon ceased.{{r|survival_report}}{{Reference page|page=1.20}} Ground observers noted a sudden increase in debris being shed, and all on-board systems lost power. By 9:00:25, the orbiter's fore and aft sections had separated from one another.{{r|survival_report}}{{Reference page|page=1.21}} The sudden [[Jerk (physics)|jerk]] caused the crew compartment to collide with the interior wall of the fuselage, resulting in the start of depressurization of the crew compartment by 9:00:35.{{r|survival_report}}{{Reference page|page=1.22}} The pieces of the orbiter continued to break apart into smaller pieces, and within a minute after breakup were too small to be detected by ground-based videos. A NASA report estimates that by 9:35, all crew remains and a majority of debris had hit the ground.{{r|survival_report}}{{Reference page|page=1.77}}

The loss of signal occurred at a time when the Flight Control Team expected brief communication outages as the orbiter stopped communication via the west [[tracking and data relay satellite]] (TDRS). Personnel in Mission Control were unaware of the in-flight break-up, and continued to try to reestablish contact with the orbiter.{{r|caib_report}}{{Reference page|page=43}} At around 9:12:39, when ''Columbia'' would have been conducting its final maneuvers to land, a Mission Control member received a phone call concerning news coverage of the orbiter breaking up. This information was immediately passed on to the Entry Flight Director, [[LeRoy E. Cain|LeRoy Cain]], who initiated contingency procedures.{{r|caib_report}}{{Reference page|page=44}} At KSC, where ''Columbia'' had been expected to land at 9:16, NASA Associate Administrator and former astronaut [[William Readdy]] also began contingency procedures after the orbiter did not land as scheduled.{{r|columbia_home|p=5}}