Research Shuttle Flight Tries Out a New Arm

THERE'S a new ``moon'' circling Earth - satellite STS-62. That's the official name for the 16th flight of Columbia, up since Friday for 14 days, one of the longest missions a United States shuttle has undertaken.

The mission involves a complex research agenda, including more on-board engineering and technological experiments than ever before. It typifies the kind of ``nitty gritty'' work needed to advance the technology of space flight. Biological and materials experiments will anticipate the kinds of research to be done on the planned space station, and other experiments will relate to the space station structure itself.

The astronauts' work includes trying out a new modification of the shuttle's maneuverable arm to grapple wobbly objects in space. Until now, astronauts using the arm have had to grab an object, such as a satellite, with a mechanical gripper at the end of the arm that caught hold of a grapple fixture post typically 10 inches long. This has involved some fumbling about, since the astronauts did not have a direct view of their target, nor could they feel what they were doing.

The National Aeronautics and Space Administration is introducing a system featuring powerful electromagnets with an attractive force of 3,200 pounds. They latch on to grapple plates on a satellite instead of the posts. Sensors provide a touch-like feedback while a mirror and TV-camera system gives a direct view of the target.

If the old arm failed and couldn't let go of an object, the astronauts might be unable to retract it and close the cargo bay doors. But with the new system, they would only have to kill the power to the magnet to release the satellite.