Columbia Space Shuttle Disaster

views updated

14 Columbia Space Shuttle Disaster

Excerpts from Columbia Accident Investigation Board Report,

Volume 1

Published in 2003; available at Columbia Accident Investigation Board

(CAIB) and NASA (Web sites)

On February 1, 2003, the National Aeronautics and Space Agency (NASA) was dealt a severe blow. The space shuttle Columbia, carrying a crew of seven, broke up while attempting to reenter Earth's atmosphere after a sixteen-day mission. It was the first major accident since 1986, when the space shuttle Challenger exploded less than two minutes after takeoff, with most of the nation watching on television. The space shuttle program, which had been regarded by many Americans as engaging in "routine" missions, came under intense examination. A thorough investigation was initiated the day following the explosion. The final report, issued on August 26, 2003, faulted NASA for the explosion because the agency had overlooked problems that had been plaguing the aging Columbia for years.

Since its founding in 1958, NASA has been successful in accomplishing its missions. Sending human beings into outer space is never a routine exercise, and the space agency has generally been credited with maintaining a good record. In fact, by the turn of the twenty-first century, NASA had made space travel seem to be an everyday occurrence. Nevertheless, for many years critics have charged that NASA officials and engineers have frequently been guilty of arrogance or indifference, which have cost astronauts their lives. Some accidents, such as the fire in the cockpit of the Apollo 1 spacecraft that killed three astronauts in 1967, were not due to negligence on the part of NASA scientists. Other fatal accidents, such as the Challenger disaster in 1986 and the Columbia explosion in 2003, were preventable. NASA officials claim that a lack of funding prevented them from performing some necessary repairs, but Congressional reports have found differently.

The Columbia mission began amidst problems on launch day, January 16, 2003. When the shuttle lifted off from Cape Canaveral, Florida, a piece of hardened foam insulation dislodged from its external fuel tank and struck the underside of its left wing. The next day, while the Columbia was in orbit, NASA engineers discussed whether the foam could have damaged heat-resistant tiles that were necessary to prevent a fire upon reentry. On January 21 and 22, NASA engineer Alan Rodney Rocha begged NASA officials to request spy satellite photos of Columbia to evaluate the extent of the damage. His requests were denied. On January 29, senior NASA official William Readdy (1952–) inquired about taking photos, but he did not make a formal request. Consequently, no photos were ever taken by NASA while the Columbia was in orbit.

On February 1, Columbia attempted reentry into the atmosphere. At 5:53 a.m. PST (Pacific Standard Time; 8:53 a.m. Eastern Standard Time [EST]), sensors on the shuttle indicated that there was trouble. An astronomer in San Francisco, California, shot five photos of the craft as it was breaking up in the atmosphere. One of the photos showed a mysterious "purple streak" trailing the craft. It was later determined to be part of Columbia's on-board camera. One minute later, at 5:54 a.m. PST, a news photographer in California observed pieces of the Columbia flying overhead. He also saw a red flare coming from the shuttle. Meanwhile, in Houston, Texas, site of NASA Mission Control, officials had lost radio contact with Columbia at 9:00 a.m. EST (6:00 a.m. PST). At the time transmission was lost, NASA engineers were attempting to explain to the crew the nature of the warning signals. The craft was scheduled to land at Cape Canaveral at 9:16 a.m. EST (6:16 a.m. PST). At 9:05 a.m. EST (6:05 a.m. PST) residents in north-central Texas

reported hearing a faint boom and then seeing trails of smoke and debris in the sky. After receiving these reports, the NASA flight director declared a contingency (emergency) and contacted search and rescue teams in the area. None of the astronauts were found. (Later, over 2,000 pieces of debris, including human remains, were found.)

President Mourns Columbia Crew

The American public responded to the Columbia explosion with shock and disbelief. For many, the Challenger explosion was still a vivid memory that haunted them every time NASA launched a shuttle. President George W. Bush (1946–; served 2001–) addressed the grieving nation approximately five hours after the Columbia broke apart over the southwestern United States. He expressed remorse for the loss of the seven astronauts: Commander Rick D. Husband (1957–2003), a U.S. Air Force colonel and mechanical engineer, had piloted the first shuttle mission to dock with the International Space Station (ISS). Pilot William C. McCool (1961–2003) was a U.S. Navy commander. Payload commander Michael P. Anderson (1959–2003), a U.S. Air Force lieutenant colonel and physicist, was in charge of the onboard science mission. Payload specialist Ilan Ramon (1954–2003) was a colonel in the Israeli Air Force and the first Israeli astronaut. Kalpana Chawla (1961–2003), an Indian-born aerospace engineer, was flying her second mission. Mission specialist David M. Brown (1956–2003) was a U.S. Navy captain and a flight surgeon. Mission specialist Laurel Clark (1961–2003), a U.S. Navy commander and flight surgeon, worked on biological experiments. President Bush reminded the American people that space flight is never "routine" and that "it is easy to overlook … the difficulties of navigating the fierce outer atmosphere of Earth."

On February 2, NASA administrator Sean O'Keefe (1956–) appointed retired U.S. Navy Admiral Harold Gehman Jr. (1942–) to head the Columbia Accident Investigation Board (CAIB). On February 3, the American public was informed that foam shed from Columbia's external tank was likely the "root cause" of the tragedy. Two days later, however, NASA reversed this statement and stated that the debris likely was not the cause of the accident. On February 7, in the face of public protest, NASA was forced to allow individuals outside of NASA to participate in the investigation. On February 8, NASA announced that it was examining a picture of Columbia taken two days after launch, which showed an object

coming off the craft. On February 10, NASA admitted that dozens of scientists had voiced concern about problems with the Columbia, particularly in regard to the foam from the external tank. On February 11, Congress began its official investigation, headed by the CAIB. Throughout the following months, NASA was forced to admit it had not heeded the advice of its own engineers. For instance, satellite photos might have provided crucial information for the rescue of Columbia's crew, though a rescue attempt most likely would have failed. NASA continued to undergo intense examination, and on August 26, 2003, the CAIB released its official findings.

The CAIB found that a joint, known as a T-seal, was shifted after foam debris from the external tank hit the left wing. Although the gap was small—.24 × 21.7 inches (0.6 × 55 centimeters)—it was large enough to rip open upon reentry. The report was highly critical of NASA's actions during the Columbia flight. The board called into question NASA's organizational techniques used to promote safety. The report called for sweeping changes in NASA's organization and the way it conducts its flights. The space shuttles remain grounded until safety changes are made.

Things to remember while reading excerpts from the Columbia Accident Investigation Board Report:

It took seven months from the time of the accident until the issue of the report. However, the government's report was highly critical of how NASA handled the shuttle flight. For instance, ground controllers did not effectively communicate information to the Columbia crew. Although nothing will bring back the seven crew members who died, the U.S. government is serious about preventing another such accident.
The investigators found that, although NASA frequently complains that the American public finds space flight to be "routine," NASA itself failed to perform the basic preparations necessary for a safe flight. Objections and warnings raised by knowledgeable scientists were largely ignored. The report cited that this was largely due to an overall arrogance on part of NASA officials.
Although the Columbia tragedy affected the American public, there is still support for NASA. According to an Associated Press poll, a majority of Americans are still in favor of space missions.

Columbia Accident Investigation Board Report, Volume 1

Report Synopsis

Designated STS-l07, this was the Space Shuttle Program's 113th flight and Columbia's 28th. The flight was close to trouble-free. Unfortunately, there were no indications to either the crew onboard Columbia or to engineers in Mission Control that the mission was in trouble as a result of a foam strike duringascent. Mission management failed to detect weak signals that the Orbiter was in trouble and take corrective action. Columbia was the first space-rated Orbiter. It made the Space Shuttle Program's first four orbital test flights. Because it was the first of its kind, Columbia differed slightly from Orbiters Challenger, Discovery, Atlantis, and Endeavour. Built to an earlier engineering standard, Columbia was slightly heavier, and, although it could reach the high-inclination orbit of the International Space Station, itspayload was insufficient to make Columbia cost-effective for Space Station missions. Therefore, Columbia was not equipped with a Space Stationdocking system, which freed up space in the pay-load bay for longer cargos, such as the sciencemodules Spacelab and Spacehab. Consequently, Columbia generally flew science missions and serviced the Hubble Space Telescope.

STS-107 was an intense science mission that required the seven-member crew to form two teams, enabling round-the-clock shifts. Because the extensive science cargo and its extra power sources required additional checkout time, the launch sequence and countdown were about 24 hours longer than normal. Nevertheless, the countdown proceeded as planned, and Columbia was launched from Launch Complex 39-A on January 16, 2003, at 10:39 a.m. Eastern Standard Time (EST).

At 81.7 seconds after launch, when the Shuttle was at about 65,820 feet and traveling at Mach 2.46 (1,650 miles per hour), a large piece of hand-crafted insulating foam came off an area where the Orbiter attaches to the External Tank. At 81.9 seconds, it struck the leading edge of Columbia's left wing. This event was not detected by the crew on board or seen by ground support teams until the next day, during detailed reviews of all launch camera photography and videos. This foam strike had no apparent effect on the daily conduct of the 16-day mission, which met all its objectives.

The de-orbit burn to slow Columbia down for re-entry into Earth's atmosphere was normal, and the flight profile throughout re-entry was standard. Time during re-entry is measured in seconds from "Entry Interface," anarbitrarily determined altitude of 400,000 feet where the Orbiter begins to experience the effects of Earth's atmosphere. Entry Interface for STS-107 occurred at 8:44:09 a.m. on February 1. Unknown to the crew or ground personnel, because the data is recorded and stored in the Orbiter instead of being transmitted to Mission Control at Johnson Space Center, the first abnormal indication occurred 270 seconds after Entry Interface. Chapter 2 [of the Board's report] reconstructs in detail the events leading to the loss of Columbia and her crew, and refers to more details in theappendices. In Chapter 3, the Board analyzes all the information available to conclude that the direct, physical action that initiated the chain of events leading to the loss of Columbia and her crew was the foam strike during ascent.This chapter reviews fiveanalytical paths —aerodynamic, thermodynamic, sensor data timeline, debris reconstruction, andimaging evidence —to show that all five independently arrive at the same conclusion. The subsequent impact testing conducted by the Board is also discussed.

That conclusion is that Columbia re-entered Earth's atmosphere with a pre-existingbreach in the leading edge of its left wing in thevicinity of Reinforced Carbon-Carbon (RCC) panel 8. This breach, caused by the foam strike on ascent, was of sufficient size to allow superheated air (probably exceeding 5,000 degrees Fahrenheit) to penetrate the cavity behind the RCC panel. The breach widened, destroying the insulation protecting the wing's leading edge support structure, and the superheated air eventually melted the thin aluminum wingspar. Once in the interior, the superheated air began to destroy the left wing. This destructive process was carefully reconstructed from the recordings of hundreds of sensors inside the wing, and from analyses of the reactions of the flight control systems to the changes in aerodynamic forces.

By the time Columbia passed over the coast of California in the pre-dawn hours of February 1, at Entry Interface plus 555 seconds, amateur videos show that pieces of the Orbiter were shedding. The Orbiter was captured on videotape during most of its quick transit over the Western United States. The Board correlated the events seen in these videos to sensor readings recorded during re-entry. Analysis indicates that the Orbiter continued to fly its pre-planned flight profile, although, still unknown to anyone on the ground or aboard Columbia, her control systems were working furiously to maintain that flight profile. Finally, over Texas, just southwest of Dallas-Fort Worth, the increasing aerodynamic forces the Orbiter experienced in thedenser levels of the atmosphere overcame thecatastrophically damaged left wing, causing the Orbiter to fall out of control at speeds in excess of 10,000 mph….

Chapter 7: The Accident's Organizational Causes

In the Board's view, NASA's organizational culture and structure had as much to do with this accident as the External Tank foam. Organizational culture refers to the values, norms, beliefs, and practices that govern how an institution functions. At the most basic level, organizational culture defines the assumptions that employees make as they carry out their work. It is a powerful force that can persist through reorganizations and the reassignment of key personnel.

Given that today's risks in human space flight are as high and the safety margins as razor thin as they have ever been, there is little room for overconfidence. Yet the attitudes and decision-making of Shuttle Program managers and engineers during the events leading up to this accident were clearly overconfident and oftenbureaucratic in nature. Theydeferred to layered andcumbersome regulations rather than the fundamentals of safety.

The Shuttle Program's safety culture is straining to hold together thevestiges of a oncerobust systems safety program.

As the Board investigated the Columbia accident it expected to find a vigorous safety organization, process, and culture at NASA, bearing little resemblance to what the Rogers Commission identified as the ineffective "silent safety" system in which budget cuts resulted in a lack of resources, personnel, independence, and authority. NASA's initial briefings to the Board on its safety programsespoused a riskaversephilosophy that empowered any employee to stop an operation at the mere glimmer of a problem. Unfortunately, NASA's views of its safety culture in those briefings did not reflect reality. Shuttle Program safety personnel failed to adequatelyassess anomalies and frequently accepted critical risks withoutqualitative orquantitative support, even when the tools to provide more comprehensive assessments were available.

Similarly, the Board expected to find NASA's Safety and Mission Assurance organization deeply engaged at every level of Shuttle management: the Flight Readiness Review, the Mission Management Team, the Debris Assessment Team, the Mission Evaluation Room, and so forth. This was not the case. In briefing after briefing, interview after interview, NASA remained in denial: in the agency's eyes, "there were no safety-of-flight issues," and no safety compromises in the long history of debris strikes on the Thermal Protection System. The silence of Program-level safety processes undermined oversight; when they did not speak up, safety personnel could not fulfill their stated mission to provide "checks and balances." A pattern of acceptance prevailed throughout the organization that tolerated foam problems without sufficient engineering justification for doing so.

What happened next …

As a result of the CAIB report, NASA administrator O'Keefe grounded all future shuttle missions. In January 2004 President Bush announced that the space shuttle fleet will be retired from service in 2010. NASA plans to replace the shuttle with the Crew Exploration Vehicle, which is expected to conduct its first manned mission by 2014 (see George W. Bush entry).

Did you know …

After the explosion, many Americans feared that terrorists had somehow been involved. Terrorism was quickly ruled out as a possible cause of the accident.
On March 26, 2003, the United States House of Representatives's Science Committee approved funds for the construction of a memorial at Arlington National Cemetery for the Columbia crew. A similar memorial was built for the Challenger crew.
On January 6, 2004, NASA announced that the landing site for the Mars Rover Spirit would be called Columbia Memorial Station. NASA also announced that a series of hills on Mars are being named for individual Columbia crew members.

Consider the following …

Although NASA has come under considerable fire for the Challenger and Columbia tragedies, the space agency has been extremely successful. Do you think flights should resume? Why or why not? Should NASA continue to use the existing shuttles, many of which are nearly thirty years old, or is it a good idea to build new crafts for a new age of exploration?
Many people are still very angry that NASA officials might have been able to prevent the 1986 and 2003 shuttle accidents. Do you think that there should be a nongovernment agency that investigates NASA's work so as to help prevent another accident? Why or why not?
Ask your parents or teacher where they were when the space shuttle Challenger exploded. Ask them how they felt and if they think space flight should continue. Do you remember the Columbia disaster? How did it make you feel?

For More Information

Books

Cabbage, Michael, and William Harwood. Comm Check: The Final Flight of Shuttle Columbia. New York: Free Press, 2004.

Cole, Michael D. Columbia Space Shuttle Disaster: From First Liftoff to Tragic Final Flight. Berkeley Heights, NJ: Enslow Publishers, 2003.

Periodicals

Cowen, R. "Columbia Disaster." Science News (February 8, 2003): pp. 83–84.

"A Fall to Earth." U.S. News & World Report (2003 Special Commemorative Issue): pp. 24–25.

Web Sites

Columbia Accident Investigation Board Report, Volume 1. NASA: Washington, DC, 2003. Available at CAIB.http://www.caib.us/news/report/default.html (accessed on August 10, 2004); also available at NASA.http://www.nasa.gov/columbia/home/CAIB_Vol1.html (accessed on August 10, 2004).

"NASA Honors the STS–107 Crew and Their Dedication to the Spirit of Exploration and Discovery." NASA.http://www.nasa.gov/columbia/home/index.html (accessed on August 10, 2004).

"Space Shuttle Columbia Disaster." Wikipedia.http://en.wikipedia.org/wiki/Columbia_disaster (accessed on August 10, 2004).

Ascent: Rising or mounting upward.

Inclination orbit: Angle at which a celestial body crosses Earth's equator, and its altitude above Earth. A high-inclination orbit means that the path between Earth and the ISS is at such a steep angle that a space shuttle must maintain a high level of thrust, or speed, which can be slowed down by heavy cargo.

Payload: Load carried by an aircraft or spacecraft consisting of things (such as passengers or instruments) necessary to the purpose of the flight.

Docking: Joining of two spacecraft in space.

Modules: Independently operable units that are part of the total structure of a space vehicle.

Arbitrarily: Randomly, without a discernible pattern or reason.

Appendices: Supplemental material usually attached at the end of a piece of writing.

Analytical paths: Ways of thinking; division of a topic or problem into logical parts and the evaluation of each part individually.

Aerodynamic: The motions of and forces associated with air and other gases, especially as they interact with objects moving through them.

Thermodynamic: Of or operating by mechanical power derived from heat.

Sensor data timeline: A record of how sensing devices recorded events, in the order in which they occurred.

Imaging evidence: Evidence captured by imaging techniques such as film and photography.

Breach: Broken, ruptured, or torn condition or area.

Vicinity: Nearby area.

Spar: Part of the wing that supports the ribs.