By DPA
Washington : Experts know that there’s no space travel without risk, but in the days leading up to Tuesday’s launch of the shuttle Discovery on its next construction mission, the discussion has been unusually overt.
Wayne Hale, the manager of the shuttle programme, conceded last week that the shuttle “is not a safe vehicle by any normal standard”, but defended the decision that launching the Discovery involved “acceptable risk”.
The aging spacecraft, which has flown 30 missions in its 24 years, is set to lift off at 3.38 p.m. GMT Tuesday from Kennedy Space Centre at Cape Canaveral, Florida. Two days later, it is scheduled to dock at the orbiting International Space Station.
Objections by NASA’s safety engineers were overruled by NASA officials. They urged a postponement of launch to allow replacement of three defective heat shield tiles on the leading edge of Discovery’s wings.
The Columbia shuttle disintegrated in 2003 when it re-entered Earth’s atmosphere, exploding as super-heated air entered the cabin. All seven astronauts on board died.
The disaster was blamed on defects in the heat shield caused by tumbling insulation foam when the craft launched. The safety team was formed after that crash to give independent advice on launch decisions. In the ensuing missions, new safety equipment has allowed closer examination and repairs of shuttles after launch if defects are found.
The seven astronauts on board Discovery have a packed programme ahead of them, with huge construction projects including an addition of the first new room in six years to the International Space Station, where three orbiting astronauts will help in the tasks.
The past several shuttle missions have transported and mounted huge solar panels outside the station, in preparation for expanding the orbiting crew and workspace by 2010, when NASA intends to retire the shuttle programme.
The major push on this mission focuses on installing the Harmony module to serve as a port for additional international laboratories constructed in Japan, Germany and elsewhere. The European module Columbus is to be attached to Harmony in December.
Five space walks are scheduled for the tasks, including repositioning the 17.5-tonne solar array and truss that the past several missions have spent building.
Despite the cautionary signals from the safety team, Pamela Melroy, the mission’s commander, was optimistic about the flight.
“There’s a time when you need to talk, and the Flight Readiness Review was the time to talk. And then there is a time to go do it, and I’m happy to say that we’re really here and ready to go do it,” she told journalists.
The veteran crew includes Paolo Nespoli, an Italian representing the European Space Agency and Daniel Tani, an American astronaut, who will remain behind at the space station as part of the orbiting crew. Discovery is expected to bring home Clayton Anderson, who has been in orbit since June.