The space shuttle Discovery today roared flawlessly into orbit in a bold attempt to salvage two satellites aimlessly circling the globe since last February.

Lifting into a blue Florida sky from the Kennedy Space Center at 7:15 a.m., astronauts Frederick H. Hauck, David M. Walker, Joseph P. Allen, Anna L. Fisher and Dale A. Gardner encountered scattered clouds but none of the high winds that forced a one-day launch delay Wednesday. The rising shuttle left a trail of red and white exhaust clouds at least 10 miles long.

"We had an absolutely 100-percent working vehicle at liftoff," Launch Operations Director Robert Sieck said later. "Even the weather cooperated with us."

After reaching orbit, the five astronauts began performing the first of 44 intricate orbital maneuvers that will edge them toward rendezvous with a pair of errant communications satellites. They will try to retrieve the satellites next week, returning them to Earth for reuse.

Flight Director Jay Greene called the eight-day flight the "most challenging" space mission since the Apollo moon landings more than a decade ago.

"We've deployed satellites before, we've picked up satellites before, we've rendezvoused before and we've repaired a satellite before," Greene said at Houston's Johnson Space Center. "But we've never before done all of these things together on one flight."

The crew was in buoyant spirits. "That was a tremendous lift," Gardner told astronaut Dick Richards in Houston's Mission Control Center. "We really enjoyed the ride."

On their second orbit, as Discovery flew in darkness over Indonesia, Walker told Mission Control that the spaceliner had passed directly over an erupting volcano somewhere near New Guinea.

"We just saw a bright glow down there that looks like it might be a volcano," Walker said. "It's somewhere in Indonesia where two islands butt up against each other and very close to the water."

By the end of the day, Discovery was in an orbit below and behind the two communications satellites -- Palapa and Westar VI -- which were about 720 miles apart on the same orbital path 225 miles high.

"We'll be getting higher and closer all the time for the next few days," Greene said. "If things go well, we'll be station-keeping flying in formation with Palapa sometime Sunday."

The astronauts first plan to deploy two new communications satellites before taking up the salvage operation.

A satellite belonging to Telesat of Canada will be placed in orbit on Friday and another being leased by the U.S. Navy from Hughes Aircraft Corp. will float from the cargo bay on Saturday.

Both satellites eventually are to be positioned by onboard engines in "geosynchronous" orbit 22,400 miles above the Equator, where they will match the rotational speed of Earth and hover over the same spots. The Canadian satellite will be lined up with the border of the provinces of Alberta and Saskatchewan while the Navy satellite will hover off the coast of Brazil.

The Palapa and Westar satellites that the Discovery's crew will try to salvage went awry when their onboard engines flamed out within seconds and left them in orbits no more than 600 miles high where it was impossible to use them for Earth-to-space communications.

On Monday, Allen and Gardner plan to move out into the cargo bay as Hauck and Walker maneuver the spaceliner to within 35 feet of the Palapa satellite.

Wearing a jet-powered backpack, Allen is to attach himself to the satellite using a six-foot "stinger" device that resembles an umbrella held backwards. Allen will push a probe into the bell-shaped engine nozzle at one end of the satellite, attaching himself to the engine bell.

Allen then will use his backpack jets to stop the satellite's slow rotation and begin to reel it in toward the open cargo bay. Fisher, the fourth U.S. woman and the first mother in space, will use the shuttle's 50-foot robot arm to grab the satellite and help Allen bring it into the cargo bay.

Reversing their roles, Gardner and Allen will repeat the same procedures Wednesday when they attempt to retrieve the Westar VI satellite built for Western Union but now, like Palapa, owned by the underwriters that insured the satellites' original owners against their loss last February.