When Endeavour next lifts off, as soon as today if the countdown goes according to plan, the shuttle mission should give us the most detailed 3-D view of Earth yet - information that will be of use to everyone from geologists and land-use planners to the US military.
Most important, the 11-day mission will provide a snapshot of what the planet looks like at the start of a new millennium. The maps it produces - which will be 30 times more precise than existing ones - can be used by future generations as a sort of baseline for studying natural and human-made changes that occur to the planet in centuries to come.
The map should be accurate to within 98 feet, and will help scientists spot volcanoes, trace fault lines, and pursue studies that require detailed knowledge of terrain. Only the United States and much of Australia, Europe, and New Zealand now have digital maps with that resolution, NASA reports. Elsewhere, mapping is fuzzier, and much of Earth isn't reliably mapped at all.
Endeavour's radar will see through clouds that often hamper optical mapping. A six-person crew is taking a 13-ton radar system into orbit 145 miles high. Two radar antennas - one in the shuttle cargo bay, one on a mast extending 197 feet to the side - will provide stereo imaging. It will record enough data to fill the equivalent of 15,000 CDs.
An international mission, the crew includes European Space Agency astronaut Gerhard Thiele. If the radar mast doesn't unfold properly, he will be called upon to don a spacesuit and fix it.
Endeavour's scheduled launch today comes after a delay of several months, while NASA fixed wiring problems in the shuttle fleet.
Then, over the weekend, the space agency revealed that shuttle Discovery flew six times with a faulty part - one that should have been sent to the scrap heap - on its main engine. Engineers noticed unusual wear on an engine pump seal after Discovery's Hubble telescope repair mission last month, but officials insist the shuttle was never in danger.
NASA officials said it's unlikely a similar mistake was made on Endeavour, but flight engineers were reviewing their records Sunday at presstime before deciding whether to send Endeavour into space.
Meanwhile, last week NASA reported results from John Glenn's historic second space mission in October 1998. NASA physiologists, speaking at the National Institutes of Health in Bethesda, Md., said they were surprised by the vigor Mr. Glenn showed during the flight. David Williams, NASA life sciences division director, said this exploded the myth that all seniors are frail. Glenn's experience showed that seniors, with good nutrition and exercise, can be fit enough to go into space, he said.
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