Worries About Space Shuttle Relaunch |
| Written by spacetravel.org | |||
| Sunday, 01 May 2005 21:53 | |||
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The shuttle is essential to President Bushs goal of putting a man on the moon cheaply because it is the only vehicle capable of hoisting the heavy payload and crew needed to complete the construction of the ISS. The station is scheduled to be finished in 2010, and then its operation will transfer to NASAs international partners, most notably the European Space Agency. This will free up billions of dollars for NASA to use to send a craft to the moon. Columbias accident was caused by a briefcase-sized piece of insulating foam breaking loose from the shuttles external fuel tank seconds after launch and striking the orbiters left wing, punching a hole in the wings leading edge. When Columbia reentered the Earths atmosphere at about 20,000 kilometers per hour, superheated gases entered the wing, destroying Columbia from the inside out. The Columbia Accident Investigation Board (CAIB), an independent panel set up by NASA, blamed the accident on budget tightening, safety compromises, political agendas and culture problems. It listed 15 tasks that NASA should complete for the shuttles to be safe to fly again. Most of these tasks are related to the problem of critical ascent debris, pieces of foam, ice and other detritus that might fall off the shuttle as it launches, causing life-threatening damage to the orbiter. To spot any falling debris, NASA has installed many cameras on the fuel tanks and orbiter, and nine extra cameras around the launch pad and along the Atlantic coastline. These nine cameras will monitor Discoverys ascent as it lifts off from the Kennedy Space Center in Florida. NASA engineers have fitted 60 accelerometers to each wing to gauge the wings strength and to detect any impacts. Temperature sensors have been added to show how heat spreads across the wings during flights. The shuttles robot arm has been equipped with a camera and laser scanner so it can search for damage, and has been doubled in length so it can reach around the shuttle and examine its wings and nose. The astronauts have already been rehearsing how to patch up the thousands of thermal tiles lining the underside of the orbiter, in case any damage is found. NASA has completed eight of CAIBs fifteen recommendations. Many items, however, are still outstanding. For example, although the crew has been rehearsing, they are still not ready to repair damage to insulating tiles and wings in orbit, the problem of breakaway foam has not been solved, and the carbon fiber panels on the wings have not been strengthened. Nevertheless, NASA will probably allow the launch to go forward, even if some of the recommendations havent been met in time. NASA needs to make another 28 trips to the ISS to complete the station. Some experts are questioning whether the three-shuttle fleet can handle this. Jean Gebman, an aeronautical engineer and expert on the deterioration of aircraft structures at RAND Corporation in Santa Monica, is worried about fatigue and corrosion. He wishes that CAIB had spent more time focusing on corrosion and fatigue, which is potentially as dangerous as critical ascent debris. CAIB member and Stanford University physicist Douglas Osheroff says that each mission has approximately a 1 to 2 percent chance of critical failure, which translates into a 24 to 43 percent chance that an orbiter and its crew will be lost sometime during the next 28 missions. Osheroff is afraid that Bushs goal to reach the moon will put more pressure on the shuttle's launch schedule, jeopardizing safety even further. According to CAIB, pressure to complete an ISS module was one of the main reasons for cutting corners regarding safety prior to Columbias launch. NASA is now being asked to fly the shuttles 28 times by 2010 to complete the ISS, while creating new space vehicles and beginning missions to the moon.
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