Ending what one official called the "most remarkable salvage mission" tried in space, the crew of the space shuttle Discovery breathed life today into a drum-shaped communications satellite dead in orbit since April.

"The shuttle's motto is, 'We Deliver,' and they did," said Steven Dorfman, president of Hughes Communications Corp., which owns the satellite.

"We are still concerned that exposure to very cold temperatures may have caused permanent damage to the satellite, but we are all encouraged by what we saw today," he added.

Of greatest encouragement to the satellite's owners were the first signals beamed back from it since deployment April 13.

The signals indicated that temperatures in the outer shell of the drum-shaped satellite are normal, suggesting that the inner drum holding the two onboard rocket engines and more than 7,500 pounds of rocket fuel might have survived the varying temperatures of space and be ready to carry the satellite into permanent position 22,300 miles above Earth.

"We'll have a good handle on what we call the pulse of the satellite sometime on Monday," Hughes Vice President Marvin Mixon said. "But, even if the pulse is good, we still won't know if the engine will turn over until we tell it to fire two months from today."

No matter what happens then, astronauts James D. van Hoften and William F. Fisher were lavishly praised after what Dorfman said was the "most remarkable salvage mission in the history" of the space age.

"We are all happy with the outcome today," Dorfman said. "These men demonstrated what the shuttle and the manned space program are all about."

Continuing where they ended their seven-hour spacewalk Saturday, van Hoften and Fisher again donned spacesuits and worked outside in the cargo bay for almost 4 1/2 hours to prepare the 15,000-pound satellite for release.

They placed a "space blanket" over its engine bell to increase its warmth in the weeks ahead and then attached a long bar to one side of the huge drum. In the process, one of them lost a power screwdriver in space.

That seemingly harmless accident represents a potential collision hazard for a subsequent shuttle crew flying the same orbit.

Using the shuttle's mechanical arm from inside the cockpit, astronaut John M. Lounge raised the satellite 35 feet above the cargo bay and placed its center of gravity on a straight line with that of Discovery. Outside, van Hoften stepped into foot restraints on the end of the arm, and Lounge lifted him to the satellite.

Reaching as far as he could, van Hoften placed gloved hands on the attached bar and pushed down as hard as he could. As the 14-foot-wide satellite began to spin, van Hoften pushed down three more times.

The force sent the satellite spinning evenly into space over the equator near the west coast of South America where officials plan to operate it as a Navy radio relay.

"Well done," cried Discovery Commander Joe H. Engle from inside the cockpit. "Good push, Ox," said Fisher, referring to the 6-foot-4, 220-pound van Houten by his nickname.

"The advantage Ox has is the length of his arms. He was able to get a stronger push. I'm not sure another astronaut could have done it as easily," flight director William Reeves said of van Hoften, the biggest person in the 103-member astronaut corps.

When Discovery and the satellite had circled Earth and moved over the Pacific Ocean, a signal was sent from Guam to activate the satellite transmitter. If the salvage attempt were successful, the satellite would respond.

"Good news, guys," astronaut George D. Nelson radioed from Mission Control in Houston. "We've commanded the satellite, and we're getting back a signal."

"Hey, that's great," Engle said.

Minutes later, Engle said he could see the satellite spinning 20 miles ahead of Discovery. "It's sparkling up there in the sun," he said. Nelson answered: "It's not the only thing that's sparkling up there, guys."

A message teleprinted to Discovery read: "Tremendous performance. Obvious to all your work was a superbly coordinated team effort. You set the standards with one of the best rendezvous sequences we've ever seen, and your team was up to that level of outstanding performance all day long. We're all proud of you."

At the end of the message from Mission Control was another note from the crew members' wives, reading: "Click your red shoes three times and say, 'There's no place like home!' Love, Toto."

Discovery is scheduled to land before dawn Tuesday at Edwards Air Force Base in California