Largest Manmade Satellite in Orbit

SPACE CENTER, Houston--In an extraordinary display of scientific cooperation between two former rivals, an American shuttle was closing in on a Russian space outpost yesterday for a joyous linkup high above Earth.

Both ships, the shuttle Atlantis and the space station Mir, had crews from both countries. Atlantis was ferrying a fresh pair of cosmonauts to Mir for the next two months; the Mir crew--two Russians and American Norman Thagard--looked forward to returning to Earth next week aboard the shuttle.

After years of negotiations aimed at melding space efforts that have become prohibitively expensive for either nation alone, space officials hoped the union would be a milestone in the effort to build an international space station.

Commander Robert "Hoot" Gibson had the demanding task of steering the 100-ton Atlantis to within three inches of the 123-ton Mir, at a closing rate no faster than one foot in 10 seconds, while the two ships sped in tandem around the Earth at 17,500 mph.

He had only two minutes to do this, so that Mir could maintain contact with a Russian ground station. The shuttle has no such constraints; it is in near-constant contact with Mission Control via satellite.

The danger was that the two behemoths would bump with too much force.

"It's not an easy thing to do, but ...it's the kind of thing you can train to do," Gibson, a former fighter and test pilot, said before the flight. "It's kind of along the lines of some of the stuff I used to do, air-to-air refueling and any of those precision tasks."

Not since the joining of a three-person Apollo capsule with a two-person Soyuz spacecraft 20 years ago next month--with a highly ballyhooed bear hug in space--had there been such a joint effort.

The docking, 245 miles above central Asia, was to test a technique needed for building an international space station beginning in 1997.