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Space Shuttle Challenger disaster

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   The iconic image of Space Shuttle Challenger's smoke plume after its
   breakup 73 seconds after launch. The accident caused the death of all
   seven members of the STS-51-L mission.
   Enlarge
   The iconic image of Space Shuttle Challenger's smoke plume after its
   breakup 73 seconds after launch. The accident caused the death of all
   seven members of the STS-51-L mission.

   The Space Shuttle Challenger disaster was a space disaster that
   occurred at 11:39 a.m. EST on January 28, 1986, when the NASA Space
   Shuttle Challenger disintegrated 73 seconds into its flight after an
   O-ring seal in its right solid rocket booster (SRB) failed. The seal
   failure caused a flame leak from the solid rocket booster that impinged
   upon the adjacent external propellant tank. Within seconds, the flame
   caused structural failure of the external tank, and the orbiter broke
   up abruptly due to aerodynamic forces. The shuttle was destroyed and
   all seven crew members were killed, probably when the crew compartment
   hit the surface of the ocean. The crew compartment and many other
   vehicle fragments were eventually recovered from the ocean floor after
   a lengthy search and rescue operation.

   The disaster resulted in a 32-month hiatus in the shuttle program and
   the formation of the Rogers Commission, a special commission appointed
   by President Ronald Reagan to investigate the accident. The Rogers
   Commission found that NASA's organizational culture and decision-making
   processes had been a key contributing factor to the accident. NASA
   managers had failed to deal with the flawed design of the O-rings, had
   ignored warnings from engineers about the dangers of launching on such
   a cold day, and had failed to adequately report these technical
   concerns to their superiors. The Rogers Commission offered NASA nine
   recommendations that were to be implemented before shuttle flights
   resumed.

   Many schoolchildren saw the launch live due to the presence on the crew
   of Christa McAuliffe, the first member of the Teacher in Space Project.
   Media coverage of the accident was extensive: one study reported that
   85 percent of Americans surveyed in a poll had heard the news within an
   hour of the accident. The Challenger disaster has been used as a case
   study in many discussions of engineering safety and workplace ethics
   and has inspired a television movie, Challenger, which was made in
   1990.

Pre-launch conditions and delays

   Ice on the launch tower on the morning of the Challenger launch.
   Enlarge
   Ice on the launch tower on the morning of the Challenger launch.

   Challenger's launch was originally set for 2:43 pm Eastern Standard
   Time (EST) on January 22. However, delays suffered by the previous
   mission, STS-61-C, caused the launch date to be pushed back to the 23rd
   and then to the 24th. Launch was then rescheduled for the 25th due to
   bad weather at the Transoceanic Abort Landing (TAL) site in Dakar,
   Senegal. NASA decided to use Casablanca as the TAL site, but because it
   was not equipped for night landings, the launch had to be moved to the
   morning ( Florida time). Predictions of unacceptable weather at Kennedy
   Space Centre (KSC) caused the launch to be rescheduled for 9:37 am EST
   on the 27th. Launch was then delayed 24 hours when the pad technicians
   could not remove a closing fixture from the orbiter's hatch. When the
   fixture was finally sawn off, cross winds at the Shuttle Landing
   Facility exceeded the limits for a Return to Launch Site (RTLS) abort,
   and thus the launch was delayed once again.

   The morning of the 28th dawned unusually cold, with temperatures having
   dropped into the low twenties overnight. The low temperatures had
   prompted concern from engineers at Morton Thiokol, the contractor
   responsible for the construction and maintenance of the shuttle's solid
   rocket boosters. At a teleconference which took place on the evening of
   the 27th, Thiokol engineers and managers discussed the weather
   conditions with NASA managers from Kennedy Space Centre and Marshall
   Space Flight Centre. Although several engineers—most notably Roger
   Boisjoly—expressed their concern about the effect of the temperature on
   the resilience of the rubber O-rings that sealed the joints of the
   solid rocket boosters, Morton Thiokol managers in the end decided to
   recommend that the launch should go ahead.

   Due to the low temperatures, a significant amount of ice built up on
   the fixed service structure that stood beside the shuttle. Although the
   KSC ice team had worked through the night removing ice, engineers at
   Rockwell International, the shuttle's prime contractor, still expressed
   concern. They warned that ice might be shaken loose during launch, and
   might either strike the shuttle or be aspirated by its main engines.
   Managers at Rockwell told shuttle program manager Arnold Aldrich that
   they could not completely assure that the shuttle was safe to launch,
   but failed to communicate a firm recommendation against launching. As a
   result of these discussions, Aldrich decided to postpone the shuttle
   launch by an hour in order to give the ice team the time to perform
   another inspection. After that last inspection, during which the ice
   appeared to be melting, Challenger was finally cleared to launch at
   11:38 am EST.

January 28 launch and failure

Liftoff and initial ascent

   Camera captures grey smoke emitting from the right-hand SRB
   Enlarge
   Camera captures grey smoke emitting from the right-hand SRB

   The following account of the accident is derived from real time
   telemetry data and photographic analysis, as well as from transcripts
   of air-to-ground and mission control voice communications.All times are
   given in seconds after launch and correspond to the telemetry
   time-codes from the closest instrumented event to each described event.

   At 6.6 seconds before liftoff, the three space shuttle main engines
   (SSME) ignited. Until liftoff actually occurs, the SSMEs can be safely
   shut down and the launch aborted if necessary. At liftoff time (T=0,
   which was at 11:38:00.010 EST), the three SSMEs were at 100% of their
   original rated performance, and began throttling up to 104% under
   computer control. At this moment, the two SRBs were ignited and
   hold-down bolts were released with explosives, freeing the vehicle from
   the pad. With the first vertical motion of the vehicle, the gaseous
   hydrogen vent arm retracted from the External Tank (ET) but failed to
   latch back. Review of film shot by pad cameras showed that the arm did
   not re-contact the vehicle, and thus it was ruled out as a contributing
   factor in the accident. The post-launch inspection of the pad also
   revealed that kick springs on four of the hold-down bolts were missing,
   but they were similarly ruled out as a possible cause. Later review of
   launch film showed that at T+0.678, strong puffs of dark grey smoke
   were emitted from the right-hand SRB near the aft strut that attaches
   the booster to the ET. The last smoke puff occurred at about T+2.733.
   The last view of smoke around the strut was at T+3.375.
   Challenger lifts off.
   Enlarge
   Challenger lifts off.

   As the vehicle cleared the tower, the SSMEs were operating at 104%
   their rated maximum thrust, and control switched from the Launch
   Control Centre (LCC) at KSC to the Mission Control Centre (MCC) in
   Houston, Texas. To prevent aerodynamic forces from tearing the shuttle
   apart, at T+28 the SSMEs began throttling down to limit the velocity of
   the shuttle in the dense lower atmosphere. At T+35.379, the SSMEs
   throttled back further to the planned 65%. Five seconds later, at about
   19,000 feet, Challenger passed through Mach 1. At T+51.860, the SSMEs
   began throttling back up to 104% as the vehicle approached Max Q, the
   period of maximum aerodynamic pressure on the vehicle.

Plume

   Camera captures plume on right SRB
   Enlarge
   Camera captures plume on right SRB

   At T+58.788, a tracking film camera captured the beginnings of a plume
   near the aft attach strut on the right SRB. Unknown to those on
   Challenger or in Houston, ignited gas had begun to leak through a
   growing hole in one of the right-hand SRB's joints. Within a second,
   the plume became well defined and intense. Internal pressure in the
   right SRB began to drop because of the rapidly enlarging hole in the
   failed joint, and at T+60.238 there was evidence of flame through the
   rupture impinging on the external tank.

   At T+64.660, the plume suddenly changed shape, indicating that a leak
   had begun in the liquid hydrogen tank, located in the aft portion of
   the external tank. The nozzles of the main engines pivoted under
   computer control to compensate for the unbalanced thrust produced by
   the booster burn-through. The pressure in the shuttle's external liquid
   hydrogen tank began to drop at T+66.764, indicating the effect of the
   leak.

   At this stage the situation still seemed normal both to the astronauts
   and to flight controllers. At T+68, the CAPCOM informed the crew that
   they were "go at throttle up," and Commander Dick Scobee confirmed the
   call. His response, "Roger, go at throttle up," was the last
   communication from Challenger on the air-to-ground loop.

Vehicle breakup

   View of the Space Shuttle Challenger disaster from Cocoa Beach.
   Enlarge
   View of the Space Shuttle Challenger disaster from Cocoa Beach.

   At T+72.284, the right SRB apparently pulled away from the aft strut
   attaching it to the external tank. Later analysis of telemetry data
   showed a sudden lateral acceleration to the right at T+72.525, which
   may have been felt by the crew. The last statement captured by the crew
   cabin recorder came just half a second after this acceleration, when
   Pilot Michael J. Smith said "Uh oh". Smith may also have been
   responding to onboard indications of main engine performance, or to
   falling pressures in the external fuel tank.

   At T+73.124, the aft dome of the liquid hydrogen tank failed, producing
   a propulsive force that pushed the hydrogen tank into the liquid oxygen
   tank in the forward part of the ET. At the same time, the right SRB
   rotated about the forward attach strut, and struck the intertank
   structure.

   The breakup of the vehicle began at T+73.162 seconds and at an altitude
   of 48,000  feet (15  km). With the external tank disintegrating,
   Challenger veered from its correct attitude with respect to the local
   air flow and was immediately torn apart by aerodynamic forces. The two
   SRBs, which can withstand greater aerodynamic loads, separated from the
   ET and continued in uncontrolled powered flight for another 37 seconds.
   The SRB casings were one-half-inch thick steel and much stronger than
   the orbiter and ET; thus, both SRBs survived the breakup of the space
   shuttle stack, even though the right SRB was still suffering the
   effects of the joint burn-through that had set the destruction of
   Challenger in motion.

Post-breakup flight controller dialog

   In Mission Control, there was silence for a few seconds after the
   accident. Television screens showed a cloud of smoke and vapor where
   Challenger had been, with pieces of debris falling toward the ocean. At
   about T+89, flight director Jay Greene prompted his flight dynamics
   officer for information. The response was that "filters [radar] got
   discreting sources," a further indication that Challenger had broken
   into multiple pieces. The ground controller reported "negative contact,
   loss of downlink" of radio and telemetry data from Challenger.

   At T+110.250, the Range Safety Officer (RSO) at the Cape Canaveral Air
   Force Station sent radio signals that activated the range safety
   system's "destruct" packages on board both solid rocket boosters. This
   was a normal contingency procedure, undertaken because the RSO judged
   the free-flying SRBs a possible threat to land or sea. The same
   destruct signal would have destroyed the External Tank had it not
   already disintegrated.

   "Flight controllers here are looking very carefully at the situation,"
   reported the public affairs officer. "Obviously a major malfunction."
   Shortly afterwards, the flight dynamics officer relayed the range
   safety officer's report that the vehicle had exploded. Flight director
   Jay Greene then ordered that contingency procedures be put into effect
   at Mission Control; these procedures included locking the doors of the
   control centre, shutting down telephone communications with the outside
   world, and following checklists that ensured that the relevant data was
   correctly recorded and preserved.

No "explosion"

   Challenger begins to disintegrate.
   Enlarge
   Challenger begins to disintegrate.

   Contrary to the flight dynamics officer’s initial statement, the
   shuttle and external tank did not actually " explode"; there was no
   detonation. Instead they rapidly disintegrated under tremendous
   aerodynamic forces, since the shuttle was near " Max Q", or maximum
   aerodynamic pressure. When the external tank disintegrated, the fuel
   and oxidizer stored within it were released, producing the appearance
   of a massive fireball. However, according to the NASA team that
   analyzed imagery after the accident, there was only "localized
   combustion" of propellant. Instead, the visible cloud was primarily
   composed of vapor and gases resulting from the release of the shuttle's
   liquid oxygen and liquid hydrogen propellant. Stored in cryogenic
   conditions, the liquid hydrogen could not have ignited rapidly enough
   to trigger an "explosion" in the traditional sense. Had there been a
   true explosion, the entire shuttle would have been instantly destroyed,
   killing the crew at that moment. The more robustly constructed crew
   cabin and SRBs survived the breakup of the launch vehicle; while the
   SRBs were subsequently detonated remotely, the detached cabin continued
   along a ballistic trajectory, and was observed exiting the cloud of
   gases at T+75.237. Twenty-five seconds after the breakup of the
   vehicle, the trajectory of the crew compartment peaked at a height of
   65,000 feet (21.5 km); the breakup had occurred at only 48,000 feet
   (16 km).

Cause and time of death

   During vehicle breakup, the robustly constructed crew cabin detached in
   one piece and slowly tumbled. NASA estimated separation forces at about
   12 to 20 times the force of gravity (g) very briefly; however, within
   two seconds, the magnitude of the forces on the cabin had already
   dropped to below 4 g, and within ten seconds the cabin was undergoing
   free fall. These forces were likely insufficient to cause major injury.
   At least some of the astronauts were likely alive and briefly conscious
   after the breakup, because three of the four personal egress air packs
   (PEAPs) on the flight deck were found to have been activated.
   Investigators found their remaining unused air supply roughly
   consistent with the expected consumption during the 2 minute 45 second
   post-breakup trajectory. Whether the astronauts remained conscious long
   after the breakup is unknown, and largely depends on whether the
   detached crew cabin maintained pressure integrity. If it did not, time
   of useful consciousness at that altitude is just a few seconds; the
   PEAPs supplied only unpressurized air, and hence would not have helped
   the crew retain consciousness. The crew cabin impacted the ocean
   surface at roughly 207 miles per hour (333 km/hour), causing an
   instantaneous deceleration of over 200 g, far beyond the structural
   limits of the crew compartment or crew survivability levels.

   On July 28, 1986, Rear Admiral Richard H. Truly, NASA's Associate
   Administrator for Space Flight and a former astronaut, released a
   report from Joseph P. Kerwin, biomedical specialist from the Johnson
   Space Centre in Houston, Texas, relating to the deaths of the
   astronauts in the accident. Dr. Kerwin, a veteran of the Skylab 2
   mission, had been commissioned to undertake the study soon after the
   accident. According to the Kerwin Report:


   Space Shuttle Challenger disaster

   The findings are inconclusive. The impact of the crew compartment with
    the ocean surface was so violent that evidence of damage occurring in
       the seconds which followed the explosion was masked. Our final
                              conclusions are:
     * the cause of death of the Challenger astronauts cannot be
       positively determined;

     * the forces to which the crew were exposed during Orbiter breakup
       were probably not sufficient to cause death or serious injury; and

     * the crew possibly, but not certainly, lost consciousness in the
       seconds following Orbiter breakup due to in-flight loss of crew
       module pressure.


   Space Shuttle Challenger disaster

Crew escape was not possible

   During powered flight of the space shuttle, crew escape was not
   possible. While launch escape systems were considered several times
   during shuttle development, NASA's conclusion was that the shuttle's
   expected high reliability would preclude the need for one. Modified
   SR-71 Blackbird ejection seats and full pressure suits were used on the
   first four shuttle orbital missions, which were considered test
   flights, but they were removed for the operational missions that
   followed. Providing a launch escape system for larger crews was
   considered undesirable due to "limited utility, technical complexity
   and excessive cost in dollars, weight or schedule delays."

   After the loss of Challenger, the question was re-opened, and NASA
   considered several different options, including ejector seats, tractor
   rockets and bailing out through the bottom of the orbiter. However,
   NASA once again concluded that all of the launch escape systems
   considered would be impractical due to the sweeping vehicle
   modifications that would have been necessary and the resultant
   limitations on crew size. A bail-out system was designed to give the
   crew the option to leave the shuttle during gliding flight; however,
   this system would not have been available in the Challenger scenario.

Aftermath

Tributes

   The Space Shuttle Challenger Memorial, where some remains were buried.
   Enlarge
   The Space Shuttle Challenger Memorial, where some remains were buried.

   On the night of the disaster, President Ronald Reagan had been
   scheduled to give his annual State of the Union address. He initially
   announced that the address would go on as scheduled, but under mounting
   pressure he postponed the State of the Union address for a week and
   gave a national address on the Challenger disaster from the Oval Office
   of the White House. It was written by Peggy Noonan, and finished with
   the following statement, which quoted from the poem "High Flight" by
   John Gillespie Magee, Jr.:


   Space Shuttle Challenger disaster

   We will never forget them, nor the last time we saw them, this morning,
    as they prepared for their journey and waved goodbye and 'slipped the
              surly bonds of earth' to 'touch the face of God.'


   Space Shuttle Challenger disaster

   Three days later, Reagan and his wife Nancy traveled to the Johnson
   Space Centre to be present at a memorial service honoring the
   astronauts. It was attended by six thousand NASA employees, as well as
   by the families of the crew.

Funeral ceremonies

   The remains of the crew that were identifiable were returned to their
   families on April 29, 1986. Two of the crewmembers, Dick Scobee and
   Michael Smith, were buried by their families at Arlington National
   Cemetery at individual grave sites. Other crew remains were buried at
   the Space Shuttle Challenger Memorial in Arlington on May 20, 1986.

Recovery of debris

   In the first minutes after the accident, recovery efforts were begun by
   NASA's Launch Recovery Director, who ordered the ships used by NASA for
   recovery of the solid rocket boosters to be sent to the location of the
   water impact. Search and rescue aircraft were also dispatched. At this
   stage, however, debris was still falling, and the Range Safety Officer
   (RSO) held both aircraft and ships out of the impact area until it was
   safe for them to enter. It was about an hour until the RSO allowed the
   recovery forces to begin their work.
   Part of the left solid rocket booster, salvaged by search and recovery
   teams.
   Enlarge
   Part of the left solid rocket booster, salvaged by search and recovery
   teams.

   The search and rescue operations which took place in the first week
   after the Challenger accident were managed by the Department of Defense
   on behalf of NASA, with assistance from the United States Coast Guard,
   and mostly involved surface searches. According to the Coast Guard,
   "the operation was the largest surface search in which they had
   participated." This phase of operations lasted until February 7.
   Thereafter, recovery efforts were managed by a Search, Recovery and
   Reconstruction team; its aim was to salvage debris that would help in
   determining the cause of the accident. Sonar, divers, remotely-operated
   submersibles and manned submersibles were all used during the search,
   which covered an area of 480 square nautical miles, and took place at
   depths of up to 1200 feet. By May 1, enough of the right solid rocket
   booster had been recovered to determine the original cause of the
   accident, and the major salvage operations were concluded. While some
   shallow-water recovery efforts continued, this was unconnected with the
   accident investigation; it aimed to recover debris for use in NASA's
   studies of the properties of materials used in spacecraft and launch
   vehicles.

   On board Challenger was an American flag that was sponsored by Boy
   Scout Troop 514 of Monument, Colorado. It was recovered intact, still
   sealed in its cargo bag. Debris from Challenger washed up on Florida
   beaches for years after the incident. On December 17, 1996, ten years
   after the incident, two large pieces of the shuttle were found at Cocoa
   Beach.

Investigation

   In the aftermath of the accident, NASA was criticized for its lack of
   openness with the press. The New York Times noted on the day after the
   accident that "neither Jay Greene, flight director for the ascent, nor
   any other person in the control room, was made available to the press
   by the space agency". In the absence of reliable sources, the press
   turned to speculation; both the New York Times and United Press
   International ran stories suggesting that a fault with the space
   shuttle external tank had caused the accident, despite the fact that
   NASA's internal investigation had quickly focused in on the solid
   rocket boosters. "The space agency," wrote space reporter William
   Harwood, "stuck to its policy of strict secrecy about the details of
   the investigation, an uncharacteristic stance for an agency that long
   prided itself on openness."

Rogers Commission

   The Presidential Commission on the Space Shuttle Challenger Accident,
   also known as the Rogers Commission (after its chairman), was formed to
   investigate the disaster. The commission members were Chairman William
   P. Rogers, Vice Chairman Neil Armstrong, David Acheson, Eugene Covert,
   Richard Feynman, Robert Hotz, Donald Kutyna, Sally Ride, Robert Rummel,
   Joseph Sutter, Arthur Walker, Albert Wheelon, and Chuck Yeager. The
   commission worked for several months and published a report of its
   findings. It found that the Challenger accident was caused by a failure
   in the O-rings sealing a joint on the right solid rocket booster, which
   allowed pressurized hot gases and eventually flame to "blow by" the
   O-ring and make contact with the adjacent external tank, causing
   structural failure. The failure of the O-rings was attributed to a
   faulty design, whose performance could be too easily compromised by
   factors including the low temperature on the day of launch.
   Members of the Rogers Commission arrive at Kennedy Space Center.
   Enlarge
   Members of the Rogers Commission arrive at Kennedy Space Centre.

   More broadly, the report also considered the contributing causes of the
   accident. Most salient was the failure of both NASA and its contractor
   Morton Thiokol to respond adequately to the danger posed by the
   deficient joint design; rather than redesigning the joint, they came to
   define the problem as an acceptable flight risk. The report also
   strongly criticized the decision making process that led to the launch
   of Challenger, saying that it was seriously flawed.


   Space Shuttle Challenger disaster

    ...failures in communication... resulted in a decision to launch 51-L
    based on incomplete and sometimes misleading information, a conflict
        between engineering data and management judgments, and a NASA
   management structure that permitted internal flight safety problems to
                        bypass key Shuttle managers.


   Space Shuttle Challenger disaster

   One of the commission's most well-known members was theoretical
   physicist Richard Feynman. During a televised hearing, he famously
   demonstrated how the O-rings became less resilient and subject to seal
   failures at ice-cold temperatures by immersing a sample of the material
   in a glass of ice water. He was so critical of flaws in NASA's "safety
   culture" that he threatened to remove his name from the report unless
   it included his personal observations on the reliability of the
   shuttle, which appeared as Appendix F. In the appendix, he argued that
   the estimates of reliability offered by NASA management were wildly
   unrealistic, differing as much as a thousandfold from the estimates of
   working engineers. "For a successful technology," he concluded,
   "reality must take precedence over public relations, for nature cannot
   be fooled."

U.S. House Committee hearings

   The U.S. House Committee on Science and Technology also conducted
   hearings, and on October 29, 1986 released its own report on the
   Challenger accident. The committee reviewed the findings of the Rogers
   Commission as part of its investigation, and agreed with the Rogers
   Commission as to the technical causes of the accident. However, it
   differed from the committee in its assessment of the accident's
   contributing causes.


   Space Shuttle Challenger disaster

     ...the Committee feels that the underlying problem which led to the
   Challenger accident was not poor communication or underlying procedures
   as implied by the Rogers Commission conclusion. Rather, the fundamental
     problem was poor technical decision-making over a period of several
        years by top NASA and contractor personnel, who failed to act
     decisively to solve the increasingly serious anomalies in the Solid
                           Rocket Booster joints.


   Space Shuttle Challenger disaster

NASA response

   After the Challenger accident, further shuttle flights were suspended,
   pending the results of the Rogers Commission investigation. Whereas
   NASA had held an internal inquiry into the Apollo 1 fire, its actions
   after Challenger were more constrained by the judgments of outside
   bodies. The Rogers Commission offered nine recommendations on improving
   safety in the space shuttle program, and NASA was directed by President
   Ronald Reagan to report back within thirty days as to how it planned to
   implement those recommendations.

   In response to the commission's recommendation, NASA initiated a total
   redesign of the space shuttle's solid rocket boosters, which was
   watched over by an independent oversight group as stipulated by the
   commission. NASA's contract with Morton Thiokol, the contractor
   responsible for the solid rocket boosters, included a clause stating
   that in the event of a failure leading to "loss of life or mission,"
   Thiokol would forfeit $10 million of its incentive fee and formally
   accept legal liability for the failure. After the Challenger accident,
   Thiokol agreed to "voluntarily accept" the monetary penalty in exchange
   for not being forced to accept liability.

   NASA also created a new Office of Safety, Reliability and Quality
   Assurance, headed as the commission had specified by a NASA associate
   administrator who reported directly to the NASA administrator. George
   Martin, formerly of Martin Marietta, was appointed to this position.
   Former Challenger flight director Jay Greene became chief of the Safety
   Division of the directorate.

   The unrealistically optimistic launch schedule pursued by NASA had been
   criticized by the Rogers Commission as a possible contributing cause to
   the accident. After the accident, NASA attempted to aim at a more
   realistic shuttle flight rate: it added another orbiter, Endeavour, to
   the space shuttle fleet in order to replace Challenger, and it worked
   with the Department of Defense in order to put more satellites in orbit
   using expendable launch vehicles rather than the shuttle. In August
   1986, President Reagan also announced that the shuttle would no longer
   carry commercial satellite payloads. After a 32-month hiatus, the next
   shuttle mission, STS-26, was launched on September 29, 1988.

   Although significant changes were made by NASA after the Challenger
   accident, many commentators have argued that the changes in its
   management structure and organizational culture were neither deep nor
   long-lasting. After the Space Shuttle Columbia disaster in 2003,
   attention once again focused on the attitude of NASA management towards
   safety issues. The Columbia Accident Investigation Board (CAIB)
   concluded that NASA had failed to learn many of the lessons of
   Challenger. In particular, the agency had not set up a truly
   independent office for safety oversight; the CAIB felt that in this
   area, "NASA's response to the Rogers Commission did not meet the
   Commission's intent". The CAIB believed that "the causes of the
   institutional failure responsible for Challenger have not been fixed,"
   saying that the same "flawed decision making process" that had resulted
   in the Challenger accident was responsible for Columbia's destruction
   seventeen years later.

Popular impact

Use as case study

   The Challenger accident has frequently been used as a case study in the
   study of subjects such as engineering safety, the ethics of
   whistleblowing, communications and group decision-making. Roger
   Boisjoly, the engineer who had warned about the effect of cold weather
   on the O-rings, left his job at Morton Thiokol and became a speaker on
   workplace ethics. He argues that the caucus called by Morton Thiokol
   managers, which resulted in a recommendation to launch, "constituted
   the unethical decision-making forum resulting from intense customer
   intimidation." Universities such as Texas A&M and the University of
   Texas have also used the accident in classes on the ethics of
   engineering.

   The graphic designer Edward Tufte has used the Challenger accident as
   an example of the problems that can occur when information is
   incorrectly presented. He argues that if Morton Thiokol engineers had
   more clearly presented the data that they had on the relationship
   between cold temperatures and burn-through in the solid rocket booster
   joints, they might have succeeded in persuading NASA managers to cancel
   the launch.
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