Space Shuttle Columbia Disaster (2003): Loss on Re-entry

The Space Shuttle Columbia disaster occurred on 1 February 2003, when the orbiter broke apart over Texas while returning from a 16-day science mission, killing all seven astronauts aboard. The cause was damage to the left wing from a chunk of foam that had struck it during launch. Coming 17 years after the loss of Challenger, the accident led to a searching investigation of NASA’s culture and to the decision to retire the shuttle.

Background: Columbia and STS-107

Columbia was NASA’s first space shuttle orbiter and had made the programme’s first flight in April 1981. Mission STS-107 was its 28th flight and the 113th of the shuttle programme.

Unlike most shuttle flights of the period, STS-107 did not visit the International Space Station. It was a dedicated research mission carrying a SPACEHAB double module, in which the crew worked around the clock in two shifts on about 80 experiments in biology, medicine, materials science and Earth observation.

The experiments included studies of how fire and combustion behave in weightlessness, observations of dust storms over the Mediterranean and Middle East, and tests on insects, plants and the growth of human cells. Some results were radioed to the ground during the mission, and a container of tiny nematode worms was later found alive among the debris.

The foam strike

Columbia lifted off from Kennedy Space Center, Florida, on 16 January 2003. About 82 seconds after launch, a piece of insulating foam roughly the size of a small suitcase and weighing about 0.75 kilograms broke away from the “bipod ramp” area of the external fuel tank. It struck the underside of the left wing’s leading edge at a relative speed of roughly 870 kilometres per hour.

The leading edge was made of reinforced carbon-carbon panels designed to withstand temperatures above 1,500 °C during re-entry. The impact, investigators later concluded, punched a hole in or near panel 8.

Engineers reviewing launch films the next day saw the strike. Some requested images of the wing from military satellites or ground telescopes, but managers did not pursue the request. An analysis based on a model intended for much smaller debris suggested no serious safety risk, and foam shedding had been seen on earlier flights without disaster, so the strike was treated as a maintenance issue.

Break-up on re-entry

On the morning of 1 February 2003 Columbia fired its engines to leave orbit and entered the upper atmosphere over the Pacific at about 8:44 a.m. Eastern time. Hot gas entered the damaged wing and began melting its internal aluminium structure.

As Columbia crossed California, Nevada and New Mexico, sensors in the left wing failed one by one and observers on the ground saw debris shedding from the orbiter. Mission Control lost voice contact at about 8:59 a.m., as the crew were acknowledging a call. Within a minute, the orbiter broke apart at about 60 kilometres altitude while travelling at around 18 times the speed of sound.

The crew’s cabin separated and broke up shortly afterwards. A later NASA study found that the crew lost consciousness within seconds of the cabin losing pressure, and that the break-up was not survivable.

The crew

The seven astronauts were commander Rick Husband, pilot William McCool, payload commander Michael Anderson, and mission specialists Kalpana Chawla, David Brown and Laurel Clark, together with payload specialist Ilan Ramon of the Israeli Air Force.

Chawla, born in India, was the first woman of Indian origin to fly in space, on an earlier Columbia mission in 1997. Ramon was Israel’s first astronaut. Anderson was one of the few African American astronauts of the period.

Ramon, the son of a Holocaust survivor, carried into space a small pencil drawing, “Moon Landscape”, made by the 14-year-old Petr Ginz in the Theresienstadt ghetto before his murder at Auschwitz. Pages of Ramon’s diary from the flight were later found among the debris in Texas and restored in Israel.

The search and the investigation

Debris fell over an area stretching from eastern Texas into Louisiana. Around 25,000 people took part in the search, recovering about 84,000 pieces, roughly 38 per cent of the orbiter by weight. Two members of a search helicopter crew died when their aircraft crashed in Texas in March 2003.

NASA set up the Columbia Accident Investigation Board, chaired by retired US Navy Admiral Harold Gehman. In July 2003 a test at Southwest Research Institute in San Antonio fired a block of foam at a real wing panel at launch speed, blowing a hole about 41 centimetres across.

The board’s report of August 2003 found that the physical cause was the foam strike. It gave equal weight to organisational causes: NASA had come to accept foam loss as normal, schedule pressure from space station assembly had grown, and safety concerns raised by engineers had not been heard. The board noted strong similarities with the Challenger disaster of 1986.

The sociologist Diane Vaughan, who had studied the Challenger accident and advised the board, described the process as a “normalisation of deviance”: each flight that survived a foam strike made the next one seem acceptable. The board made 29 recommendations, 15 of which it said had to be met before the shuttle flew again, including better imaging of launches and a stronger, independent technical authority on safety.

By the numbers

Consequences

The remaining shuttles were grounded until the STS-114 mission of July 2005. NASA redesigned the external tank, added cameras, and introduced inspections of the heat shield in orbit with a boom-mounted sensor, as well as a plan to shelter crews on the space station if a shuttle was found to be damaged.

In January 2004 President George W. Bush announced the Vision for Space Exploration, which called for the shuttle to be retired after the space station was finished. The last shuttle flight landed in July 2011.

The crew were honoured in many ways. A memorial was dedicated at Arlington National Cemetery, seven asteroids were named after the astronauts, and in 2004 the team operating the Spirit rover named a range of hills on Mars the Columbia Hills, with individual peaks named for each crew member.

Timeline

• 2003, 16 January: Columbia is launched on mission STS-107; foam strikes the left wing 82 seconds into flight.
• 2003, 17 January: Engineers reviewing launch film identify the debris strike.
• 2003, 1 February, about 8:44 a.m. EST: Columbia enters the atmosphere over the Pacific.
• 2003, 1 February, about 9:00 a.m. EST: The orbiter breaks apart over Texas.
• 2003, 7 July: A foam test in San Antonio blows a large hole in a wing panel.
• 2003, 26 August: The Columbia Accident Investigation Board publishes its main report.
• 2005, 26 July: Shuttle flights resume with STS-114.
• 2011, 21 July: The space shuttle programme ends with the landing of Atlantis.

Why it matters

The Columbia disaster showed how a large organisation could come to accept a known danger as routine. Its lessons on safety culture are studied far beyond spaceflight, and it brought about the end of the space shuttle era and a shift in American plans towards new spacecraft.