For the first time in a decade, astronauts will fly free in space this month - no lifeline to the shuttle, just a jet pack intended as a life preserver for space station crews.
If the jet pack fails, Discovery's pilots will rescue the adrift astronaut as both ship and spacewalker circle the Earth at 17,500 mph.The mission commander insists that rescuing a stranded spacewalker should be as easy as snagging the satellite that's supposed to be released and retrieved during Discovery's upcoming flight.
"I feel very confident that if we get into one of these situations, we're well trained," Commander Richard Richards said. A problem with the jet pack would be "a disappointing hardware failure but not certainly a safety problem."
Discovery is scheduled to blast off Friday on a nine-day mission, assuming that NASA resolves assorted shuttle problems. The spacewalk would be one week later.
Mark Lee and Carl Meade will take turns on the jet pack for 45 minutes each during the 61/2-hour spacewalk. Neither will venture more than 25 feet from the shuttle, and only one of them will be unattached at a time. The other spacewalker will be tethered to the shuttle.
Richards and his crew have practiced spacewalker-rescue procedures in ground simulators more than 40 times.
"I don't see any greater risk in this than other things we do flying in space," Lee said.