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NASA orders fix for space shuttle tank
2007-08-24
NASA will replace cracked adhesive beneath the insulation foam on the tanks of the space shuttles, hoping to eliminate a problem that damaged Endeavour's heat shield during its launch earlier this month, the U.S. space agency said on Friday. The work is not expected to delay the shuttle Discovery's launch to install a new module on the International Space Station, currently scheduled for October 23, said shuttle program manager Wayne Hale. "It is rather heartening that we can get on with the repair that will improve our safety," Hale told reporters in a conference call. NASA has had problems with insulation flying off fuel tanks during launch and hitting the space shuttles. Columbia was destroyed and its seven astronauts killed after its heat shield was damaged by a suitcase-sized chunk of foam. During Endeavour's launch on August 8, a baseball-sized piece of foam, mixed with either its underlying adhesive or ice, fell off the tank, bounced off a metal strut and bashed into the ship's belly, damaging two heat-resistant, ceramic tiles. NASA ran tests and computer simulations for six days during the ship's mission to determine if the gash would lead to more serious damage when Endeavour flew through the atmosphere for landing. Temperatures in the area where the shuttle was hit reach about 2,000 degrees Fahrenheit (1,093 degrees Celsius). NASA said the crew was never in any danger as the ship's structure would remain intact. The tests showed the cut did not need to be patched during a spacewalk and Endeavour landed safely at the Kennedy Space Center on Wednesday. The space agency took X-rays of the tank set to fly on NASA's next mission in October and found underlying cracks in an adhesive used to hold the foam to the tank. The affected areas are foam coverings on four of five metal brackets that hold the oxygen feed line to the outside of the tank. The foam and defective adhesive will be removed and the area covered with a slightly different type of insulation, Hale said. The work, which is expected to begin Sunday or Monday at the Kennedy Space Center in Florida, should take about nine days. NASA wants to fly two more shuttle missions this year, including one to carry Europe's Columbus science laboratory to the International Space Station. The space agency needs to finish building the $100 billion orbital complex by 2010 when the shuttles are to be retired. The station is a little more than 60-percent complete.
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