By KEAY DAVIDSON
San Francisco Chronicle
August 10, 2005
The shuttle fleet - Discovery, Atlantis and Endeavour - has been grounded for the time being because of Discovery's technical troubles during this flight. NASA officials promise they won't fly again until they figure out what caused large and potentially dangerous chunks of foam to fall off the shuttle's external tank during launch.
NASA also wants to find out:
- Why two strips of insulation called "gap fillers" protruded from between heat tiles on the shuttle's underside. During the mission, emergency supercomputer simulations at NASA-Ames Research Center in Mountain View were unable to rule out the possibility that the gap fillers might cause turbulence during re-entry due to friction with Earth's atmosphere, which could cause the shuttle bottom to heat up to a dangerous, perhaps catastrophic degree. Concerned, NASA officials sent astronaut Stephen Robinson outside the spaceship to remove the protruding gap fillers.
- Why a quilted "thermal blanket" under a crew window became frayed. NASA officials worried that chunks of the blanket might fall off during re- entry and clobber a vulnerable part of the shuttle, possibly damaging it. At Ames, experts stayed up all night one night last week conducting an emergency wind tunnel test to reassure themselves that the blanket was unlikely to cause serious damage during re-entry.
Thanks to unprecedented on-board TV surveillance of Discovery's exterior during flight, NASA learned at least one big lesson from this mission: Discovery's technical problems might not be new. Indeed, such problems might have occurred on many shuttle missions before this one. If so, most shuttles' survivals might have been a matter of pure luck.
Thus, NASA officials now must decide whether to fly any shuttles ever again and, if they decide to do so, whether they should routinely conduct Robinson-style repair jobs on future flights. Routine repair work takes a lot of time. It's also potentially dangerous: Any time an astronaut walks in space, he risks exposure to micrometeoroids, unusually high radiation doses from solar flares and other hazards.
When or if the shuttle will fly again is a question of real urgency. For diplomatic reasons, the United States is committed to building the international space station, the still-unfinished jewel in NASA's orbital crown. The shuttle is needed to complete the station.
The United States has agreements with Russia to build and supply the station and to ferry astronauts from Europe and Japan there. Some space visionaries, eager to soothe brewing political tensions between the United States and China, would like to invite the Chinese on board, too. Even if the space station as it is today is almost useless for scientific research - as some non-NASA scientists charge - advocates say the manned station is a worthwhile symbol of international peace, a sort of United Nations in orbit.
By the way, "manned" seems like an increasingly archaic word for the space shuttle's crew: Before dawn Tuesday, at the hands of Commander Eileen Collins, Discovery slid back to Earth with feline elegance. Once notorious for its sexism, NASA has become one of the most visible champions of women's rights in the federal bureaucracy. In the process it has reinforced its popularity with half of the voting, taxpaying population - the half whose mothers and grandmothers long ago remained Earthbound while men, and only men, soared for the stars.
Until the two-week Discovery flight, what happened to the Columbia shuttle 2 1/2 years ago had long since slipped from routine public conversation. Until the Discovery launch on July 26, the Columbia had begun to seem like an unlamented symbol of the NASA whose schedule-conscious managers often ignored engineers' warnings about safety hazards, like the foam that fell off Columbia's external tank and damaged its wing, dooming its seven- person crew to incineration over Texas.
Shaken, NASA spent hundreds of millions of dollars refurbishing the shuttle, thereby transforming itself, it seems, into the NASA that readily responds to engineers' safety worries, that makes sure dissenting expert opinions receive a fair airing and that readily admits goof-ups.
Thus, veteran science reporters, who are accustomed to NASA's obfuscations, were startled when, on July 27, the day after launch, shuttle program manager Bill Parsons acknowledged that foam had unexpectedly fallen off Discovery's external tank. He added: "You have to admit when you're wrong. We were wrong. We have to go do more work here. The ... foam should not have come off. It came off. We're going go do something about that."
Agreement came from Wayne Hale, the erudite yet folksy shuttle program deputy manager, who admitted that "clearly what we decided (to do) for the first flight (back to space), we didn't do it right."
Cynics might wonder if Hale's aw-shucks mea culpas reflect a deeper NASA agenda: to convince Congress that the 24-year-old shuttle fleet is such aging junk that it must be replaced as soon as possible with a shiny, new, safer, more reliable generation of manned rockets.
Michael Griffin, the new NASA administrator President Bush appointed early this year, has made no bones about his dislike for the shuttle. And his underlings have recently expressed publicly their own doubts about the vehicle. In the NASA bureaucracy nowadays, one frequently hears the shuttle compared to an old car that might no longer be worth continual expensive tuneups, and to a "camel" - a horse designed by committee, as the old joke goes.
Later this summer, NASA is expected to release more details of its plans for the next generation of manned space rockets, starring the so-called Crew Exploration Vehicle (CEV). Unlike the shuttle, which flies to orbit alongside the foam-insulated external fuel tank, the CEV would sit atop its booster rocket. Thus, falling foam wouldn't hit the CEV as it sometimes hits the shuttle.
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