NASA: Shuttle astronauts may be able to complete mapping work

Data gathered by the space shuttle Endeavour on Saturday shows a 19 mile (30 km) wide area around Karamea Bight in New Zealand with a resolution of 80 feet (25 meters)

February 15, 2000
Web posted at: 12:11 PM EST (1711 GMT)

HOUSTON (CNN) -- Thanks to fuel-efficient changes in steering and flushing aboard space shuttle Endeavour, NASA is optimistic that astronauts can complete their mapping of the world.

By Tuesday, flight controllers had come up with 17 ideas for conserving fuel aboard Endeavour, ranging from changes in shuttle maneuvers to changes in urine disposal. Five were implemented.

The problem is with a tiny nitrogen-gas valve on the end of the 197-foot (59-meter) radar antenna mast jutting out of Endeavour's cargo bay. Engineers suspect something may be jamming the fuel line that feeds the thruster and preventing it from working.

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"They think maybe some ice is blocking it," mission specialist Janice Voss told CNN on Tuesday from orbit.

Because of the lack of thrust, the astronauts have been firing Endeavour's onboard jets more often to keep the mast in the right position.

Consequently, they're using 1 1/2 times more fuel than anticipated.

The onboard thrusters keep the spacecraft in its desired orbit and orientation, and more importantly, guide it through re-entry into the atmosphere.

By constantly bathing the Earth with radar, Endeavour's six astronauts are attempting to create an unparalleled 3-D map of the world's terrain. They're using a pair of radar antennas: one on the end of the mast and one in the cargo bay.

Shuttle astronauts on Tuesday stressed that the fuel problem had not compromised the performance of the radar system.

"It's performing well. Even without that thruster we're getting superb data," Voss told reporters Tuesday morning.

Endeavour astronauts had completed mapping well over half the targeted Earth land surface by early Tuesday. More than 20 percent of the targeted land had been mapped twice.

U.S. astronaut Janet Kavandi and German astronaut Gerhard Thiele use an inflatable globe and a shuttle model for a demonstration from Endeavour's middeck Monday

The area surveyed at least once was equal to that of Africa, North America and Australia combined.

NASA had planned to map at least 70 percent of the Earth's surface over nine days during the $600 million mission, spearheaded by the Pentagon. Each missed day would represent a 10 percent loss of data.

The mast is supposed to remain extended until Sunday. Even if it has to be pulled in early and mapping is curtailed, the shuttle almost certainly would remain in orbit until February 22 as planned.

CNN Space Correspondent Miles O'Brien, The Associated Press and Reuters contributed to this report.

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