The Space Shuttle Columbia was the second space shuttle disaster and the first shuttle lost on land happened on February 1, 2003. In this mission, six American astronauts and Israel’s first spaceman died when the space shuttle Columbia disintegrated 200,000ft above Texas. They are David Brown, Rick Husband, Laurel Clark, Kalpana Chawla, Michael Anderson, William McCool and Ilan Ramon. Rick husband is the Columbia’s commander was a US air force colonel recruited to the space program in 1994. He made his first flight in 1999; last week’s was his second.
William McCool is the Columbia pilot was on his first flight. A naval commander and test pilot, he was selected for the space program in April 1996, and trained at the Johnson space centre. Michael Anderson is one of only a handful of African-American astronauts, Anderson had logged 211 hours in space before the Columbia disaster. A USAF lieutenant-colonel, he joined Nasa in 1994. Kalpana Chawla is an experienced astronaut who made her first flight on STS-87 in 1997. David Brown was a military flight surgeon before joining the astronaut corps.
Laurel Clark joined Nasa in the same year as Brown, and was trained as a space flight surgeon. Lastly is the Ilan Ramon, an Israeli air force colonel, Ramon was his country’s first astronaut. He took part in the 1973 Yom Kippur war and the 1981 bombing raid that destroyed an Iraqi nuclear reactor. With the Columbia accident, not only has the nation lost a four-billion-dollar shuttle, seven outstanding astronauts and priceless experimental results, it has also lost confidence in manned space flight and space exploration. February 1, 2003 was a sunny day.
The Columbia Reconstruction Project Team attempted to reconstruct the bottom of the orbiter as part of the investigation into the accident. The engineers found that a 20-inch piece of hardened insulation foam breaking off the main fuel tank and hitting the shuttle’s left wing during the launch on January 16th. They asked the top shuttle managers for outside agency assistance, but the request was denied. This is because the shuttle managers concluded that there was no safety concern due to the foam’s impact and decided to let the mission continue. Other possible causes were pilot mistake and space debris.
After investigations continued in the next few weeks, some molten aluminum debris from the shuttle’s wing structure, as well as molten steel debris, had been found. When the engineers eliminated the other possibilities, they began to focus on the foam from the external tank only. When the shuttle reenters the atmosphere, the temperature on its surface can reach nearly 1649oC. So the Thermal Protection System (Various materials applied to the outer structure protect the orbiter from excessive heat) on the shuttle is critical. There are four different materials in the space shuttles Thermal Protection System (TPS).
There are high-temperature reusable surface insulation (HRSI) , low-temperature reusable surface insulation (LRSI), felt reusable surface insulation(FRSI), and reinforced carbon-carbon composite (RCC). The HRSI cover the high surface temperature reaches between 649 and 1260oC. The LRSI cover the low surface temperature reaches between 371 and 649oC. For another 2 materials are used in small amounts. Due to the temperature during reentry exceeds 1260oC at the nose cap, chin panel, forward external tank, and wing leading edge panels and T-seals, the RCC was break down.
For reuse purpose and to prevent oxidation, the outer layer of the RCC is converted into silicon carbide in a furnace filled with argon with a temperature cycle up to 1649oC. The main reason of the shuttle to break down is because the foam from the bipod of the external tank was shed, and struck the shuttle’s left wing during the launch. It had damaged the wing’s leading edge RCC structures which allowing reentry plasma to penetrate and disintegrate the underlying aluminum, damaging the wing’s structure.
The foam of the bipod ramp is BX-250, polyurethane foam applied with CCF-11 which is used to cover outside of the tank to prevent ice and frost on the surface. The foam is to reduce the weight so it made by light material. The engineers couldn’t believe that such a light material could damage the wing of the shuttle. Thus, some research had done by the Southwest Research institute. They used a compressed air gun to fire a foam block of similar size and mass to that which struck Columbia and at same estimated speed.
To represent the leading edge of Columbia’s left wing, RCC panels from Enterprise and from NASA stock, along with fiberglass mock-up panels, were mounted to a simulating structural metal frame. In the final round of testing, a block fired at the side of an RCC panel created a hole 41 by 42. 5 centimeters (16 by 17 in) in the protective RCC panel. The tests clearly show that the foam could cause visible crack on the tested RCC panels. These cracks could lead the shuttle breakup during reentry. The final report of the Columbia Accident Investigation was released on August 26th, 2003.
It concluded that this tragedy was caused by technical and organizational failures. The foam problem of the bipod area has existed for years, and NASA engineers have looked at a variety of ways to correct it. The report indicated that the space shuttle should not have been launched with this problem extant. The report further proposed that, although the shuttle had always returned to earth safely after the foam hit the wing during previous shuttle flights, the managers at NASA should not have rejected the engineers’ requests to make sure Columbia’s wing was not damaged this time.
Finally, it suggested that NASA should have had a backup plan for fixing the shuttle in space and insuring the crew’s safety if they found out the wing was badly damaged. On 26th July 2005, a shuttle discovery was launched. NASA had formed an independent Return to Flight (RTF) panel to monitor its preparations. There are 7 out of the 26 RTF panel members issued a minority report prior to the launch. They questioning if Columbia’s lessons had been learned and also expressing concerns about NASA’s efforts.
During launch, a large piece of foam separated from the external fuel tank, but fortunately did not strike the shuttle, which landed safely 14 days later. The shuttle fleet was once again grounded, pending resolution of the problem with the external fuel tank insulating foam. Reference: Columbia space shuttle disaster 2003. World news. http://www. guardian. co. uk/gall/0,,888045,00. html Space shuttles thermal protection system (TPS). US Centennial of Flight Commission. http://www. centennialofflight. ov/essay/Evolution_of_Technology/TPS/Tech41G2. htm Final report of Columbia Disaster. Columbia Accident Investigation Board http://caib. nasa. gov/ NASA’s Space Shuttle Program: The Columbia Tragedy, the Discovery Mission, and the Future of the Shuttle. Marcia S. Smith Resources, Science, and Industry Division. Updated by January 4, 2006. fas. org/sgp/crs/space/RS21408. pdf Lessons Learned from the Columbia Disaster. Center for Chemical Process Safety (CCPS). www. aiche. org/uploadedFiles/CCPS/… /Presentation_Rev_newv4. ppt