Funding a Dinosaur to Try To Finish the Space Station
Friday, April 28, 2006
More than three years after Columbia disintegrated over Texas, the shortcomings of the space shuttle's external fuel tank have made the nation's space program the hostage of an exasperating piece of hardware on the threshold of obsolescence.
Fourteen times since Columbia went down Feb. 1, 2003, NASA has postponed shuttle launches, and in all but one case engineers cited problems with the external tank as the main reason. Hurricane damage to NASA facilities accounted for the other.
NASA flew Discovery last year after more than two years of redesign and modifications, only to ground the fleet immediately after the tank -- a 154-foot orange torpedo that holds half a million gallons of liquid oxygen and liquid hydrogen -- shed unacceptably large pieces of foam insulation during liftoff.
Since then, the tank's vagaries have caused shuttle planners to postpone the next mission five times. Engineers are currently forging ahead on two redesigns of the insulation and tests of swapped-out tank components in hopes of making a July 1 launch date, and John Chapman, manager of NASA's external tank project, said in a telephone interview that "things are so far looking good."
So far. The loss of insulating foam is the external tank's basic flaw, known since the first shuttle flight in 1981 but largely ignored until a 1.67-pound piece of it punched a hole in Columbia's thermal tiles during launch, causing it to burn up on reentry.
Since then, NASA engineers have chipped away at the problem, but they acknowledge that it can never be truly fixed as long as America's signature spaceship is mounted alongside its volatile fuel supply, where foam can hit it.
"We have a unique design," N. Wayne Hale, shuttle program manager, said in a telephone interview. "Maybe I wish we hadn't done it this way, but it is what it is." The shuttle "will be an experimental vehicle until the last time we fly it," said Hale, who is joining NASA Administrator Michael D. Griffin to brief reporters today on NASA's efforts to ready Discovery for a July launch.
Dealing with the tank has exacted a price. Between 2003 and the end of 2005, NASA officials estimated spending $1.3 billion on post-Columbia "return to flight" expenses, many of which involved the external tank.
The consequences for the space program as a whole, however, are much grimmer: Between the Columbia tragedy and Sept. 30, 2005, NASA spent about $10 billion on the shuttle -- 26 percent of its total budget -- and flew just once.
This year, NASA has $4.8 billion for the shuttle and plans to fly twice. It hopes to fly 17 times in all before retiring the orbiter in 2010 and replacing it with a new spaceship. NASA, supposedly the most forward-looking agency in the federal government, is using the biggest single chunk of its budget to fund a dinosaur.
But the agency has no choice: "Conventional wisdom before Columbia was that foam can't be a problem because there's not enough mass," Hale said. "But the people who thought about it didn't think hard enough. Think, instead, about straws driven into a board by hurricanes."
NASA troubleshooters have solved individual tanks' problems but have failed to find a comprehensive solution. Discovery's foam loss last year was unforeseen and unrelated to the casualty that doomed Columbia.