|Date||February 1, 2003|
|Time||08:59 EST (13:59 UTC)|
|Location||Over Texas and Louisiana|
|Cause||Wing damage from debris during launch|
|Outcome||Loss of seven crew and Columbia; Space Shuttle fleet grounded for 29 months|
|Inquiries||Columbia Investigation Board|
The Space Shuttle Columbia disaster was a fatal incident in the United States space program that occurred on February 1, 2003, when the Space Shuttle Columbia (OV-102) disintegrated as it reentered the atmosphere, killing all seven crew members. The disaster was the second fatal accident in the Space Shuttle program, after the 1986 breakup of Challenger soon after liftoff.
During the STS-107 launch, a piece of the insulative foam broke off from the Space Shuttle external tank and struck the thermal protection system tiles on the orbiter's left wing. Similar foam shedding had occurred during previous Space Shuttle launches, causing damage that ranged from minor to nearly catastrophic,: 121 but some engineers suspected that the damage to Columbia was more serious. Before reentry, NASA managers had limited the investigation, reasoning that the crew could not have fixed the problem if it had been confirmed. When Columbia reentered the atmosphere of Earth, the damage allowed hot atmospheric gases to penetrate the heat shield and destroy the internal wing structure, which caused the orbiter to become unstable and break apart.
After the disaster, Space Shuttle flight operations were suspended for more than two years, as they had been after the Challenger disaster. Construction of the International Space Station (ISS) was put on hold; the station relied entirely on the Russian Roscosmos State Space Corporation for resupply for 29 months until Shuttle flights resumed with STS-114 and for crew rotation for 41 months until STS-121.
NASA made several technical and organizational changes to subsequent missions, including adding a thorough on-orbit inspection to determine how well the shuttle's thermal protection system (TPS) had endured the ascent, and keeping a designated rescue mission ready in case irreparable damage was found. Except for one final mission to repair the Hubble Space Telescope, subsequent shuttle missions were flown only to the ISS to allow the crew to use it as a haven if damage to the orbiter prevented safe reentry.
Main article: Space Shuttle
The Space Shuttle was a partially-reusable spacecraft operated by the U.S. National Aeronautics and Space Administration (NASA).: 5, 195 It flew for the first time in April 1981,: III–24 and was used to conduct in-orbit research,: III–188 and deploy commercial,: III–66 military,: III–68 and scientific payloads.: III–148 At launch, it consisted of the orbiter, which contained the crew and payload, the external tank (ET), and the two solid rocket boosters (SRBs).: 363 The orbiter was a reusable, winged vehicle that launched vertically and landed as a glider.: II-1 Five operational orbiters were built during the Space Shuttle program.: 5 Columbia was the first space-rated orbiter constructed, following atmospheric test vehicle Enterprise. The orbiter contained the crew compartment, where the crew predominantly lived and worked throughout a mission.: II-5 Three Space Shuttle main engines (SSMEs) were mounted at the aft end of the orbiter and provided thrust during launch.: II-170 Once in space, the crew maneuvered using the two smaller, aft-mounted Orbital Maneuvering System (OMS) engines.: II-79
The orbiter was protected from heat during reentry by the thermal protection system (TPS), a thermal soaking protective layer around the orbiter. In contrast with previous US spacecraft, which had used ablative heat shields, the reusability of the orbiter required a multi-use heat shield.: 72–73 During reentry, the TPS experienced temperatures up to 1,600 °C (3,000 °F), but had to keep the orbiter vehicle's aluminum skin temperature below 180 °C (350 °F). The TPS primarily consisted of four types of tiles. The nose cone and leading edges of the wings experienced temperatures above 1,300 °C (2,300 °F), and were protected by reinforced carbon-carbon tiles (RCC). Thicker RCC tiles were developed and installed in 1998 to prevent damage from micrometeoroid and orbital debris.: II–112–113 The entire underside of the orbiter vehicle, as well as the other hottest surfaces, were protected with high-temperature reusable surface insulation. Areas on the upper parts of the orbiter vehicle were coated in a white low-temperature reusable surface insulation, which provided protection for temperatures below 650 °C (1,200 °F). The payload bay doors and parts of the upper wing surfaces were coated in reusable felt surface insulation, as the temperature there remained below 370 °C (700 °F).: 395
Two solid rocket boosters (SRBs) were connected to the ET, and burned for the first two minutes of flight.: II-222 The SRBs separated from the ET once they had expended their fuel and fell into the Atlantic Ocean under a parachute.: II-289 NASA retrieval teams recovered the SRBs and returned them to the Kennedy Space Center, where they were disassembled and their components were reused on future flights.: II-292
When the Space Shuttle launched, the orbiter and SRBs were connected to the external tank, which held the fuel for the SSMEs.: II-222 The ET consisted of a larger tank for liquid hydrogen (LH2), stored at −253 °C (−423 °F) and a smaller tank for liquid oxygen (LOX), stored at −183 °C (−297 °F). It was covered in insulative foam to keep the liquids cold and prevent ice forming on the tank's exterior. The orbiter connected to the ET via two umbilicals near its bottom and a bipod near its top section.: 50−51 After its fuel had been expended, the ET separated from the orbiter and reentered the atmosphere, where it would break apart during reentry and its pieces would land in the Indian or Pacific Ocean.: II-238
During the design process of the Space Shuttle, a requirement of the ET was that it would not release any debris that could potentially damage the orbiter and its TPS. The integrity of the TPS components was necessary for the survival of the crew during reentry, and the tiles and panels were only built to withstand relatively minor impacts. On STS-1, the first flight of the Space Shuttle, the orbiter Columbia was damaged during its launch from a foam strike. Foam strikes occurred regularly during Space Shuttle launches; of the 79 missions with available imagery during launch, foam strikes occurred on 65 of them.: 121–122
The bipod, which connects near the top of the ET to the front underside of the orbiter via a ramp at the end of each strut, was also covered in foam to prevent ice from forming that could damage the orbiter. The foam on each bipod ramp was approximately 30 by 14 by 12 inches (76 by 36 by 30 cm), and was carved by hand from the original foam application. Bipod ramp foam from the left strut had been observed falling off the external tank on six flights prior to STS-107, and had created some of the largest foam strikes that the orbiter experienced. The first bipod ramp foam strike occurred during STS-7; the orbiter's TPS was repaired after the mission but no changes were made to address the cause of the bipod foam loss.: 123 After bipod foam loss on STS-32, NASA engineers, under the assumption that the foam loss was due to pressure buildup within the insulation, added vent holes to the foam to allow gas to escape. After a bipod foam strike damaged the TPS on STS-50, internal NASA investigations concluded it was an "accepted flight risk" and that it should not be treated as a flight safety issue. Bipod foam loss occurred on STS-52 and STS-62, but neither events were noticed until the investigation following Columbia's destruction.: 124
During STS-112, which flew in October 2002, a 4 by 5 by 12 inches (10 by 13 by 30 cm) chunk of bipod ramp foam broke away from the ET bipod ramp and hit the SRB-ET attachment ring near the bottom of the left SRB, creating a dent 4 inches (10 cm) wide and 3 inches (8 cm) deep.: 124 Following the mission, the Program Requirements Control Board declined to categorize the bipod ramp foam loss as an in-flight anomaly. The foam loss was briefed at the STS-113 Flight Readiness Brief, but it was stated that the ET was safe to fly.: 125
A debris strike from the ablative material on the right SRB caused significant damage to Atlantis during the STS-27 launch on December 2, 1988. On the second day of the flight, the crew inspected the damage using a camera on the remote manipulator system. The debris strike removed a tile; the exposed orbiter skin was a reinforced section, and a burn-through may have occurred if the damage was in a different location. After the mission, the NASA Program Requirements Control Board designated the issue as an in-flight anomaly that was corrected with the planned improvement for the SRB ablator.: 127
Main article: STS-107
For STS-107, Columbia carried the SpaceHab Research Double Module, the Orbital Acceleration Research Experiment, and an Extended Duration Orbiter pallet.: 30 The mission passed its pre-launch certifications and reviews, and began with the launch. The mission was originally scheduled to launch on January 11, 2001, but it was delayed 13 times, until its launch on January 16, 2003.: 28
The seven-member crew of STS-107 were selected in July 2000.: 28 The mission was commanded by Rick D. Husband, who was a colonel in the U.S. Air Force and a test pilot. He has previously flown on STS-96. The mission's pilot was William C. McCool, a U.S. Navy commander who was on his first spaceflight. The payload commander was Michael P. Anderson, a U.S. Air Force lieutenant colonel who had previously flown on STS-89. Kalpana Chawla, served as the flight engineer; she had previously flown on STS-87. David M. Brown and Laurel Blair Salton Clark, both U.S. Navy captains, flew as the mission specialists on their first spaceflights. Ilan Ramon, a colonel in the Israeli Air Force and the first Israeli astronaut, flew as a payload specialist.: 29
At T+0, Columbia launched from the Kennedy Space Center Launch Complex 39A (LC-39A) at 10:39:00 a.m. At T+81.7 seconds, a piece of foam approximately 21 to 27 inches (53 to 69 cm) long and 12 to 18 inches (30 to 46 cm) wide broke off from the left bipod on the ET. At T+81.9 seconds, the foam struck the reinforced carbon-carbon (RCC) panels on Columbia's left wing at relative velocity of 625 to 840 feet per second (426 to 573 mph; 686 to 922 km/h).: 34 The debris strike was not noticed by the mission or ground crew at the time.: 140 The SRBs separated from the ET at T+2 minutes and 7 seconds, followed by the ET separating from the orbiter at T+8 minutes 30 seconds.: 35 The ET separation was photographed by Anderson and recorded by Brown, but they did not record the bipod with missing foam.: 148 At T+43 minutes, Columbia completed its orbital insertion as planned.: 35
After Columbia entered orbit, the NASA Intercenter Photo Working Group conducted a routine review of videos of the launch. The group's analysts did not notice the debris strike until the second day of the mission. None of the cameras recording the launch had a clear view of the debris striking the wing, resulting in the group being unable to determine the level of damage sustained by the orbiter. The group's chair contacted Wayne Hale, the program manager for launch integration, to request on-orbit imagery of Columbia's wing to assess its damage. After receiving notification of the debris strike, engineers at NASA, United Space Alliance, and Boeing created the Debris Assessment Team and began working to determine the damage to the orbiter.: 140, 143 Intercenter Photo Working Group believed that the orbiter's RCC tiles were possibly damaged, while NASA program managers were less concerned over the danger caused by the debris strike.: 141
Boeing analysts attempted to model the damage caused to the orbiter's TPS from the foam strike. The software models predicted damage that was deeper than the thickness of the TPS tiles, indicating that the orbiter's aluminum skin would be unprotected in that area. The Debris Assessment Team dismissed this conclusion as inaccurate, due to previous instances of predictions of damage greater than the actual damage. Additional modeling specific to the RCC panels used software calibrated to predict damage caused by falling ice. The software predicted only one of 15 scenarios that ice would cause damage, leading the Debris Assessment Team to conclude there was minimal damage due the lower density of foam to ice.: 143–145
To assess the possible damage to Columbia's wing, members of the Debris Assessment Team made multiple requests to get imagery of the orbiter from the Department of Defense (DoD). Imagery requests were channeled through both the DoD Manned Space Flight Support Office and the Johnson Space Center Engineering Directorate.: 150–151 Wayne Hale, the Shuttle Program Manager for Launch Integration, coordinated the request through a DoD representative at KSC. The request was relayed to the U.S. Strategic Command (USSTRATCOM), which began identifying imaging assets that could observe the orbiter. The imagery request was soon rescinded by NASA Mission Management Team Chair Linda Ham after she investigated the origin of it; she had asked about the imaging requirement from a flight director but not the Debris Assessment Team.: 152–153 Maneuvering the orbiter to allow its left wing to be imaged would have interrupted ongoing science operations, and Ham dismissed the DoD imaging capabilities as insufficient to assess damage to the orbiter.: 153–154 Following the rejection of their imagery request, the Debris Assessment Team did not make additional requests for the orbiter to be imaged.: 157
Through the flight, members of the Mission Management Team were less concerned than the Debris Assessment Team about the potential risk of a debris strike. The loss of bipod foam on STS-107 was compared to previous foam strike events, none of which caused the loss of an orbiter or crew. Ham, scheduled to work as an integration manager for STS-114, was concerned with the potential delays that may be caused by a foam loss event.: 147–148 Mission management also downplayed the risk of the debris strike in communications with the crew.: 161 On January 23, flight director Steve Stich sent an e-mail to Husband and McCool to tell them about the foam strike and inform them there was no cause for concern about damage to the TPS, as foam strikes has occurred on previous flights.: 159
During ascent at approximately 80 seconds, photo analysis shows that some debris from the area of the -Y ET Bipod Attach Point came loose and subsequently impacted the orbiter left wing, in the area of transition from Chine to Main Wing, creating a shower of smaller particles. The impact appears to be totally on the lower surface and no particles are seen to traverse over the upper surface of the wing. Experts have reviewed the high speed photography and there is no concern for RCC or tile damage. We have seen this same phenomenon on several other flights and there is absolutely no concern for entry.: 159
The crew were also sent a 15-second video of the debris strike in preparation for a press conference, but were reassured that there were no safety concerns.: 161
On January 26, the Debris Assessment Team concluded that there were no safety concerns from the debris strike. The team's report was critical of the Mission Management Team for asserting that there were no safety concerns before the Debris Assessment Team's investigation had been completed.: 164 On January 29, William Readdy, the Associate Administrator for Space Flight, agreed to DoD imaging of the orbiter, but on the condition that it would not interfere with flight operations; ultimately, the orbiter was not imaged by the DoD during the flight. At a Mission Management Team on January 31, the day before Columbia reentered the atmosphere, the Launch Integration Office voiced Ham's intention to review on-board footage to view the missing foam, but concerns of crew safety were not discussed.: 166
Columbia was scheduled to reenter the atmosphere and land on February 1, 2003. At 08:30 am UTC (02:30 am EST), the Entry Flight Control Team started its shift at the Mission Control Center.: 38 On board the orbiter, the crew stowed loose items and prepared their equipment for reentry.: 1.5 At 45 minutes prior to the deorbit burn, Husband and McCool began working through the entry checklist.: 1.6 At 01:10 pm (UTC), the Capsule Communicator (CAPCOM) informed the crew that they were approved to conduct the deorbit burn. At 1:15:30 pm UTC, the crew successfully executed the deorbit burn, which lasted for 2 minutes and 38 seconds. At 1:44:09 pm UTC, Columbia reentered the atmosphere at an altitude of 400,000 feet (120 km), a point named Entry Interface (EI). Four and a half minutes after EI, a sensor began recording greater-than-normal amounts of strain on the left wing; the sensor's data was recorded to an internal recorder and not transmitted to the crew or ground controllers.: 38 The orbiter began to 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.: 1.8 This was followed by sensors in the left wheel well reporting a rise in temperature.: 1.10
At 1:53:46 pm UTC, Columbia crossed over the California coast; it was traveling at Mach 23 at an altitude of 231,600 feet (70.6 km), and the temperature of its wings' leading edges was estimated to be 2,800 °F (1,540 °C).: 38 Soon after it entered California airspace, the orbiter shed several pieces of debris, which were observed on the ground as sudden increases in brightness of the air around the orbiter. The MMACS officer reported that the hydraulic sensors in the left wing had readings below the sensors' minimum detection thresholds at 1:54:24 pm UTC. Columbia continued its reentry and traveled over Utah, Arizona, New Mexico, and Texas, where observers would report seeing signs of debris being shed.: 39
At 1:58:03 pm UTC, the orbiter's aileron trim changed from the predicted values from the increasing drag caused by the damage to the left wing. At 1:58:21 pm UTC, the orbiter shed a TPS tile that would later land in Littlefield, Texas; it would become the westernmost piece of recovered debris.: 1.12 The crew first received an indication of a problem at 1:58:39 pm 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, as well as still in the stowed position.: 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 Reaction Control System (RCS) thrusters began firing continuously to correct its orientation.: 1.14
The loss of signal (LOS) from Columbia occurred at 1:59:32 pm. Mission control stopped receiving information from the orbiter at this time, and Husband's last radio call of "Roger, uh..." was cut off mid-transmission.: 39 : 1.14 One of the channels in the flight control software was bypassed as the result of a failed wire, and a Master Alarm began sounding on the flight deck.: 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 pitch-up maneuver.: 1.16 The orbiter began flying along a ballistic trajectory, which was significantly steeper and had more drag than the previous gliding trajectory.: 1.17 The orbiter, while still traveling faster than Mach 15, entered into a flat spin of 30° to 40° per second. The acceleration that the crew was experiencing increased from approximately 0.8 g to 3 g, which would have likely caused dizziness and disorientation, but not incapacitation.: 1.18 The autopilot was switched to manual control and reset to automatic mode at 2:00:03 pm; 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 2:00:05 pm.: 1.20
At 2:00:18 pm, the orbiter began a catastrophic breakup, and all on-board data recording soon ceased.: 1.20 Ground observers noted a sudden increase in debris being shed, and all on-board systems lost power. By 2:00:25 pm, the orbiter's fore and aft sections had separated from one another.: 1.21 The sudden jerk caused the crew compartment to collide with the interior wall of the fuselage, resulting in a depressurization of the crew compartment by 2:00:35 pm.: 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 from ground-based videos. By 2:35 pm, all debris and crew remains were estimated to have impacted the ground.: 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 and reestablish contact with the orbiter.: 43 At approximately 2:12 pm, when Columbia would be conducting its final maneuvers to land, a Mission Control member received a phone call that discussed news coverage of the orbiter breaking up. This information was passed onto the Entry Flight Director, LeRoy Cain, who initiated contingency procedures.: 44
During reentry, all seven of the STS-107 crew members were killed, but the exact time of their deaths could not be determined. The level of acceleration they experienced during crew module breakup was not lethal.: 77 The first lethal event the crew experienced was the depressurization of the crew module. The rate and exact time of depressurization could not be determined, but occurred no later than 2:00:59 pm. The remains of the crew members indicated they all experienced depressurization. The astronauts' helmets have a visor that, when closed, can temporarily protect the crew member from depressurization. Some of the crew members had not closed their visor, and one was not wearing a helmet, indicating that depressurization occurred quickly before they could take protective measures.: 1.24 : 103
During and after the breakup of the crew module, the crew, either unconscious or dead, experienced rotation on all three axes. The astronauts' shoulder harnesses were unable to prevent trauma to their upper bodies, as the inertia reel system failed to retract sufficiently to secure them, leaving them only restrained by their lap belts. Additionally, the helmets were not conformal to the crew members' heads, allowing for head injuries inside of the helmet. The neck ring of the helmet may have also acted as a fulcrum that caused spine and neck injuries. The physical trauma to the astronauts, who were not able to brace to prevent such injuries, could have also resulted in their deaths.: 1.25 : 103-105
The astronauts also likely suffered from significant thermal trauma. Hot gas entered the disintegrating crew module, burning the crew members, whose bodies were still somewhat protected by their ACES suits. Once the crew module fell apart, the astronauts were violently exposed to windblast and a possible shock wave, which stripped their suits from their bodies. The crews' remains were exposed to hot gas and molten metal as they fell away from the orbiter.: 106-108
After separation from the crew module, the bodies of the crew members entered an environment with almost no oxygen, very low atmospheric pressure, and both high temperatures caused by deceleration, and extremely low ambient temperatures.: 93 Ultimately, the bodies of the crew impacted the ground with lethal levels of force.: 1.29
At 14:04 EST (19:04 UTC), President George W. Bush said in a televised address to the nation, "My fellow Americans, this day has brought terrible news, and great sadness to our country. At 9 o'clock this morning, Mission Control in Houston lost contact with our Space Shuttle Columbia. A short time later, debris was seen falling from the skies above Texas. The Columbia is lost; there are no survivors."
Pieces of the spacecraft were found in more than 2,000 separate debris fields in eastern Texas, western Louisiana and the southwestern counties of Arkansas. A large amount of debris was recovered between Tyler, Texas, and Palestine, Texas. One field stretched from south of Fort Worth to Hemphill, Texas, and into Louisiana.
Along with pieces of the shuttle and bits of equipment, searchers also found human body parts, including arms, feet, a torso, and a heart. These recoveries occurred along a line south of Hemphill, Texas, and west of the Toledo Bend Reservoir. Much of the terrain being searched for the crew was densely forested and difficult to traverse. The bodies of five of the seven crew of Columbia were found within three days of the shuttle's breakup; the last two were found 10 days after that.
In the months after the disaster, the largest-ever organized ground search took place. Thousands of volunteers descended upon Texas to participate in the effort to gather the Shuttle's remains. According to Michael Ciannilli, who served as Project Manager of the Columbia Research and Preservation Office, the searchers "put their life on hold to help out the nation's space program," showing "what space means to people." NASA issued warnings to the public that any debris could contain hazardous chemicals, that it should be left untouched, its location reported to local emergency services or government authorities, and that anyone in unauthorized possession of debris would be prosecuted. Some firefighters used Geiger counters to test those who had picked up debris. These same people were also asked to put their clothes into medical waste bags and use anti-microbial soap. Because of the widespread area, volunteer amateur radio operators accompanied the search teams to provide communications support.
A group of small (one-millimeter or 0.039-inch) adult Caenorhabditis elegans worms, living in petri dishes enclosed in aluminum canisters, survived reentry and impact with the ground and were recovered weeks after the disaster. The culture was found to be alive on April 28, 2003. The worms were part of a biological research in canisters experiment designed to study the effect of weightlessness on physiology; the experiment was conducted by Cassie Conley, NASA's planetary protection officer.
Debris Search Pilot Jules F. Mier Jr. and Debris Search Aviation Specialist Charles Krenek died in a helicopter crash that injured three others during the search.
Some Texas residents ignored the warnings and attempted to sell Columbia debris on eBay. At least one auction was quickly removed, but prices for Columbia merchandise such as programs, photographs and patches, went up dramatically following the disaster, creating a surge of Columbia-related listings. A three-day amnesty offered for "looted" shuttle debris brought in hundreds of illegally recovered pieces. During the amnesty period, "quite a few" individuals called about turning in property to NASA, including some who had debris from the Challenger accident.
About 40,000 recovered pieces of debris have never been identified. The largest pieces recovered include the front landing gear and a window frame.
On May 9, 2008, it was reported that data from a disk drive on board Columbia had survived the shuttle accident, and while part of the 340 MB drive was damaged, 99% of the data was recovered. The drive was used to store data from an experiment on the properties of shear thinning.
On July 29, 2011, Nacogdoches authorities told NASA that a four-foot-diameter (1.2 m) piece of debris had been found in a lake. NASA identified the piece as a power reactant storage and distribution tank.
All recovered non-human Columbia debris is stored in unused office space at the Vehicle Assembly Building, except for parts of the crew compartment, which are kept separate.
Among the recovered items was a videotape recording made by the astronauts during the start of reentry. The 13-minute recording shows the flight crew astronauts conducting routine reentry procedures and joking with each other. No crew member gives any indication of a problem. In the video, the flight-deck crew puts on their gloves and passes the video camera around to record plasma and flames visible outside the windows of the orbiter, a normal occurrence during reentry. At one point on the tape, Mission Control asked Clark to perform some small task. She replied that she was currently occupied but would get to it in a minute. "Don't worry about it," she was told. "You have all the time in the world." The recording ends about four minutes before the shuttle began to disintegrate and 11 minutes before Mission Control lost the signal from the orbiter.
NASA Space Shuttle Program Manager Ron Dittemore reported that "The first indication was loss of temperature sensors and hydraulic systems on the left wing. They were followed seconds and minutes later by several other problems, including loss of tire pressure indications on the left main gear and then indications of excessive structural heating". Analysis of 31 seconds of telemetry data which had initially been filtered out because of data corruption within it showed the orbiter fighting to maintain its orientation, eventually using maximum thrust from its Reaction Control System jets.
The investigation focused on the foam strike from the very beginning. Incidents of debris strikes from ice and foam causing damage during take-off were already well known, and had damaged orbiters, most noticeably during STS-45, STS-27, and STS-87. After the loss of Columbia, NASA incorrectly concluded that mistakes during installation were the likely cause of foam loss, and retrained employees at Michoud Assembly Facility in Louisiana to apply foam without defects. Later Michoud would discover that thermal stresses from filling and emptying the cryogenic fuel tanks caused correctly installed foam to crack, especially where multiple layers were present, leading to revised installation procedures for STS-121.
Main article: Columbia Accident Investigation Board
Following protocols established after the loss of Challenger, an independent investigating board was created immediately after the accident. The Columbia Accident Investigation Board, or CAIB, was chaired by retired U.S. Navy Admiral Harold W. Gehman, Jr., and consisted of expert military and civilian analysts who investigated the accident in detail.
Columbia's flight data recorder was found near Hemphill, Texas, on March 19, 2003. Unlike commercial jet aircraft, the space shuttles did not have flight data recorders intended for after-crash analysis. Instead, the vehicle data were transmitted in real time to the ground via telemetry. Since Columbia was the first shuttle, it had a special flight data OEX (Orbiter EXperiments) recorder, designed to help engineers better understand vehicle performance during the first test flights. The recorder was left in Columbia after the initial Shuttle test-flights were completed, and it was still functioning on the crashed flight. It recorded many hundreds of parameters, and contained very extensive logs of structural and other data, which allowed the CAIB to reconstruct many of the events during the process leading to breakup. Investigators could often use the loss of signals from sensors on the wing to track how the damage progressed. This was correlated with forensic debris analysis conducted at Lehigh University and other tests to obtain a final conclusion about the probable course of events.
Beginning on May 30, 2003, foam impact tests were performed by Southwest Research Institute. They used a compressed air gun to fire a foam block of similar size and mass to that which struck Columbia, at the same estimated speed. To represent the leading edge of Columbia's left wing, RCC panels from NASA stock, along with the actual leading-edge panels from Enterprise , which were fiberglass, were mounted to a simulating structural metal frame. At the beginning of testing, the likely impact site was estimated to be between RCC panel 6 and 9, inclusive. Over many days, dozens of the foam blocks were shot at the wing leading edge model at various angles. These produced only cracks or surface damage to the RCC panels.
During June, further analysis of information from Columbia's flight data recorder narrowed the probable impact site to one single panel: RCC wing panel 8. On July 7, in a final round of testing, a block fired at the side of an RCC panel 8 created a hole 16 by 16.7 inches (41 by 42 cm) in that protective RCC panel. The tests demonstrated that a foam impact of the type Columbia sustained could seriously breach the thermal protection system on the wing leading edge.
On August 26, 2003, the CAIB issued its report on the accident. The report confirmed the immediate cause of the accident was a breach in the leading edge of the left wing, caused by insulating foam shed during launch. The report also delved deeply into the underlying organizational and cultural issues that led to the accident. The report was highly critical of NASA's decision-making and risk-assessment processes. It concluded the organizational structure and processes were sufficiently flawed that a compromise of safety was expected, no matter who was in the key decision-making positions. An example was the position of Shuttle Program Manager, where one individual was responsible for achieving safe, timely launches and acceptable costs, which are often conflicting goals. The CAIB report found that NASA had accepted deviations from design criteria as normal when they happened on several flights and did not lead to mission-compromising consequences. One of those was the conflict between a design specification stating that the thermal protection system was not designed to withstand significant impacts and the common occurrence of impact damage to it during flight. The board made recommendations for significant changes in processes and organizational culture.
On December 30, 2008, NASA released a further report, titled Columbia Crew Survival Investigation Report, produced by a second commission, the Spacecraft Crew Survival Integrated Investigation Team (SCSIIT). NASA had commissioned this group, "to perform a comprehensive analysis of the accident, focusing on factors and events affecting crew survival, and to develop recommendations for improving crew survival for all future human space flight vehicles." The report concluded that: "The Columbia depressurization event occurred so rapidly that the crew members were incapacitated within seconds, before they could configure the suit for full protection from loss of cabin pressure. Although circulatory systems functioned for a brief time, the effects of the depressurization were severe enough that the crew could not have regained consciousness. This event was lethal to the crew."
The report also concluded:
The key recommendations of the report included that future spacecraft crew survival systems should not rely on manual activation to protect the crew.
Upgrades to the leading edge proposed in the early 1990s were not funded because NASA was working on the later-cancelled VentureStar single-stage-to-orbit shuttle replacement. Additionally, the original white paint on the fuel tanks was removed to save 600 lb (270 kg), exposing the rust-orange-colored foam; this was considered as a potential contributing factor, but was ultimately unlikely to have contributed to the foam shedding.
In 2008, NASA released a detailed report on survivability aspects of the Columbia reentry. In 2014, NASA released a further report detailing the aeromedical aspects of the disaster.
One question of special importance was whether NASA could have saved the astronauts had they known of the danger. This would have to involve either rescue or repair – docking at the International Space Station for use as a haven while awaiting rescue (or to use the Soyuz to systematically ferry the crew to safety) would have been impossible due to the different orbital inclination of the vehicles.
The CAIB determined that a rescue mission, though risky, might have been possible provided NASA management had taken action soon enough. Normally, a rescue mission is not possible, due to the time required to prepare a shuttle for launch, and the limited consumables (power, water, air) of an orbiting shuttle. Atlantis was well along in processing for a planned March 1 launch on STS-114, and Columbia carried an unusually large quantity of consumables due to an Extended Duration Orbiter package. The CAIB determined that this would have allowed Columbia to stay in orbit until flight day 30 (February 15). NASA investigators determined that Atlantis processing could have been expedited with no skipped safety checks for a February 10 launch. Hence, if nothing went wrong, there was a five-day overlap for a possible rescue. As mission control could deorbit an empty shuttle, but could not control the orbiter's reentry and landing, it is likely that it would have sent Columbia into the Pacific Ocean; NASA later developed the Remote Control Orbiter system to permit mission control to land a shuttle.
NASA investigators determined that on-orbit repair by the astronauts was possible but overall considered "high risk", primarily due to the uncertain resiliency of the repair using available materials and the anticipated high risk of doing additional damage to the Orbiter. Columbia did not carry the Canadarm, or Remote Manipulator System, which would normally be used for camera inspection or transporting a spacewalking astronaut to the wing. Therefore, an unusual emergency extra-vehicular activity (EVA) would have been required. While there was no astronaut EVA training for maneuvering to the wing, astronauts are always prepared for a similarly difficult emergency EVA to close the external tank umbilical doors located on the orbiter underside, which is necessary for reentry in the event of failure. Similar methods could have reached the shuttle left wing for inspection or repair.
For the repair, the CAIB determined that the astronauts would have had to use tools and small pieces of titanium, or other metal, scavenged from the crew cabin. These metals would help protect the wing structure and would be held in place during reentry by a water-filled bag that had turned into ice in the cold of space. The ice and metal would help restore wing leading edge geometry, preventing a turbulent airflow over the wing and therefore keeping heating and burn-through levels low enough for the crew to survive reentry and bail out before landing. The CAIB could not determine whether a patched-up left wing would have survived even a modified reentry, and concluded that the rescue option would have had a considerably higher chance of bringing Columbia's crew back alive.
Following the loss of Columbia, the Space Shuttle program was suspended. The further construction of the International Space Station (ISS) was also delayed, as the space shuttles were the only available delivery vehicle for station modules. The station was supplied using Russian uncrewed Progress ships, and crews were exchanged using Russian-crewed Soyuz spacecraft, and forced to operate on a skeleton crew of two.
Less than a year after the accident, President Bush announced the Vision for Space Exploration, calling for the Space Shuttle fleet to complete the ISS, with retirement by 2010 following the completion of the ISS, to be replaced by a newly developed Crew Exploration Vehicle for travel to the Moon and Mars. NASA planned to return the Space Shuttle to service around September 2004; that date was pushed back to July 2005.
On July 26, 2005, at 10:39 EST, Space Shuttle Discovery cleared the tower on the "Return to Flight" mission STS-114, marking the shuttle's return to space. Overall the STS-114 flight was highly successful, but a similar piece of foam from a different portion of the tank was shed, although the debris did not strike the Orbiter. Due to this, NASA once again grounded the shuttles until the remaining problem was understood and a solution implemented. After delaying their reentry by two days due to adverse weather conditions, Commander Eileen Collins and Pilot James M. Kelly returned Discovery safely to Earth on August 9, 2005. Later that same month, the external tank construction site at Michoud was damaged by Hurricane Katrina. At the time, there was concern that this would set back further shuttle flights by at least two months and possibly more.
The actual cause of the foam loss on both Columbia and Discovery was not determined until December 2005, when x-ray photographs of another tank showed that thermal expansion and contraction during filling, not human error, caused cracks that led to foam loss. NASA's Hale formally apologized to the Michoud workers who had been blamed for the loss of Columbia for almost three years.
The second "Return to Flight" mission, STS-121, was launched on July 4, 2006, at 14:37:55 (EDT), after two previous launch attempts were scrubbed because of lingering thunderstorms and high winds around the launch pad. The launch took place despite objections from its chief engineer and safety head. This mission increased the ISS crew to three. A 5-inch (130 mm) crack in the foam insulation of the external tank gave cause for concern, but the Mission Management Team gave the go for launch. Space Shuttle Discovery touched down successfully on July 17, 2006, at 09:14:43 (EDT) on Runway 15 at the Kennedy Space Center.
On August 13, 2006, NASA announced that STS-121 had shed more foam than they had expected. While this did not delay the launch for the next mission—STS-115, originally set to lift off on August 27—the weather and other technical glitches did, with a lightning strike, Hurricane Ernesto, and a faulty fuel tank sensor combining to delay the launch until September 9. On September 19, landing was delayed an extra day to examine Atlantis after objects were found floating near the shuttle in the same orbit. When no damage was detected, Atlantis landed successfully on September 21.
The Columbia Crew Survival Investigation Report released by NASA on December 30, 2008, made further recommendations to improve a crew's survival chances on future space vehicles, such as the then planned Orion spacecraft. These included improvements in crew restraints, finding ways to deal more effectively with catastrophic cabin depressurization, more "graceful degradation" of vehicles during a disaster so that crews will have a better chance at survival, and automated parachute systems.
After the Space Shuttle program was ended in 2011, no further crewed spacecraft were launched from American soil to the ISS until 2020 when SpaceX's Crew Dragon Demo-2 mission successfully carried a test crew of two NASA astronauts to the International Space Station.
On February 4, 2003, President George W. Bush and his wife Laura led a memorial service for the astronauts' families at the Lyndon B. Johnson Space Center. Two days later, Vice President Dick Cheney and his wife Lynne led a similar service at Washington National Cathedral. Patti LaBelle sang "Way Up There" as part of the service.
On March 26, the United States House of Representatives' Science Committee approved funds for the construction of a memorial at Arlington National Cemetery for the STS-107 crew. A similar memorial was built at the cemetery for the last crew of Challenger. On October 28, 2003, the names of the astronauts were added to the Space Mirror Memorial at the Kennedy Space Center Visitor Complex in Merritt Island, Florida, alongside the names of several astronauts and cosmonauts who have died in the line of duty.
A tree for each astronaut was planted in NASA's Astronaut Memorial Grove at the Johnson Space Center in Houston, Texas, not far from the Saturn V building, along with trees for each astronaut from the Apollo 1 and Challenger disasters. Tours of the space center pause briefly near the grove for a moment of silence, and the trees can be seen from nearby NASA Road 1.
On April 1, 2003, the Opening Day of baseball season, the Houston Astros honored the Columbia crew by having seven simultaneous first pitches thrown by family and friends of the crew. For the National Anthem, 107 NASA personnel carried a U.S. flag onto the field. The Astros wore the mission patch on their sleeves the entire season.
On February 1, 2004, the first anniversary of the Columbia disaster, Super Bowl XXXVIII held in Houston's Reliant Stadium began with a pregame tribute to the crew of the Columbia by singer Josh Groban performing "You Raise Me Up", with the crew of STS-114, the first post-Columbia Space Shuttle mission, in attendance.
In 2004, Bush conferred posthumous Congressional Space Medals of Honor to all 14 crew members lost in the Challenger and Columbia accidents.
NASA named several places in honor of Columbia and the crew. Seven asteroids discovered in July 2001 at the Mount Palomar observatory were officially given the names of the seven astronauts: 51823 Rickhusband, 51824 Mikeanderson, 51825 Davidbrown, 51826 Kalpanachawla, 51827 Laurelclark, 51828 Ilanramon, 51829 Williemccool. On Mars, the landing site of the rover Spirit was named Columbia Memorial Station, and included a memorial plaque to the Columbia crew mounted on the back of the high gain antenna. A complex of seven hills east of the Spirit landing site was dubbed the Columbia Hills; each of the seven hills was individually named for a member of the crew, and Husband Hill in particular was ascended and explored by the rover. In 2006, the IAU approved naming of a cluster of seven small craters in the Apollo basin on the far side of the Moon after the astronauts. Back on Earth, NASA's National Scientific Balloon Facility was renamed the Columbia Scientific Balloon Facility. Columbia Colles, a range of hills on Pluto discovered by the New Horizons spacecraft in July 2015, was named in honor of the victims of the disaster.
The airport in Amarillo, Texas was renamed to the Rick Husband Amarillo International Airport. A mountain peak in the Sangre de Cristo Range was renamed Columbia Point, and a dedication plaque was placed on the point in August 2003.
The first dedicated meteorological satellite launched by the Indian Space Research Organisation (ISRO) on September 2, 2002, named Metsat-1, was later renamed Kalpana-1 by Indian Prime Minister Atal Bihari Vajpayee in memory of India-born Kalpana Chawla.
In October 2004, both houses of Congress passed a resolution authored by U.S. Representative Lucille Roybal-Allard and co-sponsored by the entire contingent of California representatives to Congress changing the name of Downey, California's Space Science Learning Center to the Columbia Memorial Space Center. The facility is located at the former manufacturing site of the Space Shuttle orbiters.
NASA named a supercomputer "Columbia" in the crew's honor in 2004. It was located at the NASA Advanced Supercomputing Division at Ames Research Center on Moffett Federal Airfield near Mountain View, California. The first part of the system, built in 2003, known as "Kalpana" was dedicated to Chawla, who worked at Ames prior to joining the Space Shuttle program.
The Challenger Columbia Stadium in League City, Texas is named in honor of the victims of both the Columbia disaster as well as the Challenger disaster in 1986.
The 2005 album Ultimatum by The Long Winters contains the song "The Commander Thinks Aloud", which was songwriter/singer John Roderick's musing on the crew's perspective of the unexpected catastrophe. In addition, the January 30, 2015 episode of Hrishikesh Hirway's Song Exploder podcast presented an interview with John Roderick about the songwriting and recording process for "The Commander Thinks Aloud".
Taijin Kyofusho, the second song of the 2005 album Golevka by the post-rock band The Evpatoria Report, includes samples of the last communications between CAPCOM Hobaugh and commander Husband during reentry.
The Hungarian composer Peter Eötvös wrote a piece named Seven for solo violin and orchestra in 2006 in memory of the crew of Columbia. Seven was premiered in 2007 by violinist Akiko Suwanai, conducted by Pierre Boulez, and it was recorded in 2012 with violinist Patricia Kopatchinskaja and the composer conducting.
The 2008 album Columbia: We Dare to Dream by Anne Cabrera was written as a tribute to Space Shuttle Columbia STS-107, the crew, support teams, recovery teams, and the crew's families. A copy of the album on compact disc was flown aboard Space Shuttle Discovery mission STS-131 to the International Space Station by astronaut Clayton Anderson in April 2010.
The Scottish Celtic-Rock band Runrig included a song titled "Somewhere" on their album The Story (2016); the song was dedicated to Laurel Clark (who had become a fan of the band during her Navy service in Scotland), and includes a piece of her wake-up song, followed by some radio chatter, at the end.
During the moratorium quite a few individuals called about turning in property to NASA, including individuals who had debris from the Challenger accident.