MIAMI -- Imagine: floating helplessly in space, out of reach of your spacecraft. Alone in the vast darkness.
America's space program has lacked a proven self-rescue plan for spacewalking astronauts, NASA officials say.
But the crew of Endeavour plans to change that as it prepares for an ambitious weeklong voyage set to begin tonight at 7:06.
Forecasts of bad weather at the launch site and at emergency landing strips gave NASA only a 30 percent chance of an on-time launch, however. Shuttle weather officer Ed Priselac said yesterday that rain, thunderstorms, low clouds, haze and even hail were possible at the Kennedy Space Center and at touchdown sites in California, New Mexico and Africa.
"Right now, it certainly looks pretty unfavorable," Mr. Priselac said.
The mission is designed to prepare astronauts for long days in space as NASA moves closer to building Space Station Freedom and colonies on the moon and Mars.
Practicing different self-rescue techniques is a priority for the Endeavour crew, said Commander Dan Brandenstein.
"Crew rescue is very important in the space station assembly period," Mr. Brandenstein said. "Astronauts could become untethered and float away from the space station."
Endeavour's maiden voyage is packed with several firsts for the 11-year-old shuttle program:
There will be three consecutive days of spacewalking, each expected to last six to seven hours. Four astronauts plan to repair a satellite, build space station-type structures and practice self-rescue methods.
The crew will perform the most complex satellite rescue mission ever attempted. The crew must match the orbit of a wayward satellite, snag it and fit it with a rocket motor.
Some viewers will have a chance to feel as if they have a front-row seat to a satellite rescue. All conversations between the crew and mission control will be live and unedited.
"Certainly, it is a difficult mission," said G.P. Pennington, the flight director. "Yes, this is ambitious, but we are up to it."