The new space shuttle Endeavour put a half-million miles on the odometer Friday in its first day's pursuit of a $157-million satellite that is doomed without astronaut help.
The two spacecraft, each hurtling toward a meeting on Sunday, closed the gap to 5,400 miles.
Engineers for the broadcasting satellite's owners fired its thrusters by remote control for the third time, dropping the craft to a rendezvous altitude of 226 miles.
Shuttle commander Daniel C. Brandenstein plans to close in on the satellite Sunday so spacewalker Pierre J. Thuot can snatch the 12-by-17 1/2-foot cylinder from orbit. Thuot will be perched on the end of the ship's 50-foot robot arm when he attempts to snag the satellite with a specially designed tool.
The Endeavour team will then latch the satellite to a rocket motor designed to boost the craft to its proper 22,300-mile-high orbit. The satellite was left in a uselessly low altitude two years ago by a mis-wired Titan rocket.
Endeavour's crew of six men and one woman spent Friday getting ready for the mission's main event. Their checklist included lowering the cabin pressure to condition the spacewalkers and testing the robot arm, which is crucial for the three spacewalks planned during the seven-day flight.
One spacewalk is for the satellite rescue, and two are for practicing techniques to build space station Freedom.
NASA purposely gave the astronauts a relaxed schedule Friday and today and delayed the spacewalks to give the astronauts time to adjust to weightlessness.
Shuttle astronauts have never performed three spacewalks on one flight. The space agency needs that experience before trying to fix the Hubble Space Telescope next year and building a space station starting in 1995.
Endeavour's landing at Edwards Air Force Base, Calif., on Thursday will feature the first use of a shuttle drag chute.