Columbia shadow still looms
2005-08-09 20:34
Cape Canaveral - Nasa celebrated the shuttle Discovery's successful mission and safe landing on Tuesday, but the US space agency is far from overcoming the problems that caused the 2003 Columbia disaster.
While Discovery landed safely at the Edwards Air Force Base in California, its liftoff last month was not as smooth.
The first scheduled launch, on July 13, was postponed after a fuel gauge malfunctioned just two hours before liftoff in Cape Canaveral, Florida.
The sensors protect the shuttle's main engines by triggering their shutdown in the event that fuel runs unexpectedly low.
Nasa experts worked furiously for the next two weeks to figure out what was wrong with the fuel sensor, one of four. But the space agency decided to go ahead with the launch even if a fuel gauge malfunction reoccurred.
On the second launch attempt, on July 26, the fuel gauge mysteriously worked again, but another unpleasant surprise awaited Nasa.
As Discovery took off, a large piece of insulating foam peeled off the external fuel tank - a chilling reminder of the cause of the Columbia disaster.
Thankfully for Discovery's seven crew members, the foam did not strike the shuttle. But the incident prompted NASA to call off future launches.
The Atlantis shuttle is ready to launch as early as September 22 for another mission to the International Space Station, if the foam problem is believed fixed once and for all.
"We're going to try as hard as we can to get back in space this year," said Nasa administrator Michael Griffin. "But we're not going to go until we're ready to go."
Nasa took extraordinary precautions to ensure that Discovery would safely return to Earth.
While in orbit, docked on the space station, the shuttle was thoroughly inspected with cameras that allowed Nasa experts to check it for damage.
The inspection led to an unprecedented spacewalk under the shuttle as US astronaut Stephen Robinson removed two protruding pieces of fiber that risked overheating during reentry.
Nasa considered conducting another spacewalk when it discovered a tear in a thermal blanket on the shuttle skin just under the cockpit. But it eventually decided that a repair was unnecessary for a safe return.
In the end, nature delayed Discovery's return to Earth as bad weather forced it to stay in orbit an extra day. It finally landed in California instead of Cape Canaveral due to the weather.
The problems with foam, fuel sensors and protruding fibers should give Nasa plenty of work after it finishes celebrating the successful Discovery mission.
Some critics, including in Congress where NASA's budget is decided, are losing patience with the aging shuttle.
The shuttle fleet is slated for retirement in 2010 and will be replaced by a more modern space vehicle.