Discovery commander James Wetherbee exchanged waves with the crew of space station Mir on Monday while steering the shuttle toward the first convergence of American and Russian spaceships in 20 years.

Only a half-mile separated the two 100-ton spaceships, soaring 245 miles over Earth at 17,500 mph, when Discovery passed beneath the massive T-shaped outpost and Wetherbee took manual control.The Mir crew reported it could see Wetherbee through Discovery's windows and waved.

"This is the most beautiful thing I've ever seen in space," Weth-er-bee told Mission Control. One of the Mir crew broke from Russian into English and echoed, "Beautiful, beautiful."

The shuttle moved in front of Mir, where Wetherbee was firing braking jets to close to within 400 feet.

The final rendezvous phase, a close encounter that Russian space officials agreed to virtually at the last minute, had Discovery flying to within 35 feet.

Engineers from NASA and the Russian Space Agency huddled throughout the night and into the morning to discuss a steering thruster leak near the shuttle's tail that has been spewing fuel since shortly after Friday's launch.

The Russian agency insisted that unless the jet stopped leaking, Discovery would have to stay at least 400 feet from Mir. It feared that small chunks of frozen fuel might damage optical sensors on a Soyuz capsule attached to the orbiting outpost.

Mir's three cosmonauts need the capsule to return to Earth next month. There was also concern that Mir's solar panels might be contaminated. NASA engineers didn't think the leakage would damage the station but said they didn't blame the Russians for being cautious.

When Discovery and Mir were less than 50 miles apart, Mission Control passed on the good news to Wetherbee that he could proceed.

When that decision was reached, cosmonaut Vladimir Titov, the second Russian to fly aboard a U.S. shuttle, could already see Mir and was talking with its crew: Alexander Viktorenko, Yelena Kondakova and Valery Polyakov.

The Mir crew members reported that Discovery looked to them like "a large star on the horizon."

The only previous rendezvous between U.S. and Russian spaceships was the 1975 Apollo-Soyuz docking.

The current eight-day flight is a prelude to seven Atlantis-Mir dockings planned through 1997, the first this June. NASA insisted the first docking would proceed with or without the 35-foot approach by Discovery.