The space shuttle Discovery's astronauts sidled up to a satellite loaded with valuable data and plucked it from orbit, two days after it was set free to study the sun, NASA officials at Kennedy Space Center said. Commander Richard Richards steered Discovery to within 35 feet of the sun-gazing satellite, Spartan. Then astronaut Susan Helms snatched the gleaming, 2,800-pound spacecraft with the shuttle's mechanical arm. Helms tucked the boxy satellite into Discovery's cargo bay for the trip home, taking a little longer than expected to lock it in place. The shuttle's radar--used to track the satellite--had failed when Spartan was put into orbit on Tuesday and initially gave less-than-accurate measurements. But it ended up working "marvelously," Richards said.