Nasa's Next Step
Can the manned space program find a new, revitalizing mission in the wake of the Columbia tragedy?
Neither technology spinoffs nor scientific discoveries are enough to justify a manned space program, many experts say. The spinoffs so far--in computers, telecommunications, and other fields--might have been developed more cheaply on the ground, and unmanned probes pay greater dividends for science. Launius says there are only two rather nebulous reasons for humans to venture into space: survival of the species and prestige. As Friedman puts it, "We are a better people when we try to seek new knowledge." President Kennedy's decision to shoot for the moon was a Cold War bid to enhance America's technological image.
So how about another space race? China may be planning a manned launch later this year (box, Page 37) and aspires to land a crew on the moon. If China succeeds, says Democratic Rep. Nick Lampson of Texas, "we need to be on the moon saying, `Welcome, China.' " Perhaps geopolitical gamesmanship here on Earth will again propel NASA beyond orbit.
SAFETY MEASURES FOR THE SHUTTLE
NASA engineers are already at work on steps recommended by the board investigating the breakup of the space shuttle Columbia. They include changes to avert hazards like the fatal damage to Columbia's wing, along with methods for finding and even repairing damage in orbit. NASA hopes to make the fixes and get the three remaining orbiters flying again as early as next March.
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SHARPENING THE VIEW
In future liftoffs, NASA plans to watch closely for falling foam or other debris that could damage the orbiter. It is considering mounting cameras on the the external tank and the solid rocket boosters, which would view the wings and belly for any debris strikes. Several ground-based cameras already monitor liftoffs.
CATCHING THE BOLTS
On each mission, explosive bolts attaching the solid rocket boosters to the external tank blow apart to release the spent boosters. Two covers prevent the large bolts from striking the orbiter. Engineers have strengthened these covers to ensure they will do the job.
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Bolt catcher
Bolt
SECURING THE FOAM
A breakaway chunk of foam insulation 9see detail at right) from the "bipod," where connector rods secure the external tank to the orbiter, is thought to have fatally damaged Columbia. One part of the solution will be to remove insulation from the connectors and heat them instead to prevent the formation of ice, itself a hazard because it could break away during liftoff.
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Solid rocket boosters
WHY THE INSULATION?
The external tank acts as a large thermos. Inside is supercold liquid oxygen and liquid hydrogen, fuel for the shuttle's thirsty engines. The foam layer insulates the tank, keeping ice from forming on the exterior. Ice could break off during a liftoff and damage the orbiter.
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Liquid oxygen
Liquid hydrogen
Foam insulation
Metal tank
OTHER PRECAUTIONS
NASA wants to equip future shuttle crews to inspect and, if necessary, repair damage to the heat-shield tiles on the orbiter's skin and the carbon-composite material on its nose and wing edges while in orbit. For the time being, this will mean inspecting the orbiter while it docks with the international space station.
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Carbon-composite panels
Heat-shield tiles on orbiter's underside
NASA has also reached an agreement with the National Imagery and Mapping Agency to use imaging technologies, including spy satellites, to inspect the shuttle while it is in space.
Source: NASA
DOUG STERN AND STEPHEN ROUNTREE-USN&WR
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