Errant Satellite Twists Out of Shuttle’s Grasp

What had been a flawless maiden voyage for space shuttle Endeavour ran into serious trouble Sunday as astronauts attempting to snag a stranded $150-million communications satellite sent it spinning out of control.

“We’ve got to get away from this thing,” Endeavour commander Daniel C. Brandenstein, 49, said after the first of four rescue attempts pushed the Intelsat 6 satellite into an uncontrollable, 52-degree wobble.

At the Johnson Space Center, officials of the National Aeronautics and Space Administration decided to abandon further efforts to rescue the satellite Sunday and tentatively said they will make another try today. Meanwhile, they ordered Brandenstein to slowly back Endeavour away from the wildly gyrating Intelsat and trail it from a distance of between 45 and 70 miles.

“Our plan is to be successful the next time we go to capture Intelsat,” said Randy Stone, NASA operations director for the Endeavour mission. “Other than the exciting events of (Sunday) afternoon, the orbiter and the crew are in great shape.”

At the Washington headquarters of the International Telecommunications Satellite Organization, which paid NASA $93 million for the rescue mission, flight controllers predicted that they could stabilize the satellite in time for a rescue attempt today.

“Yes, we are disappointed,” said Pierre Madon, a vice president of the international communications consortium. But he added, “I’m quite sure this (Monday) will be a successful attempt.”

Shuttle commander Brandenstein had confidence too. “We wish the home team had won today, but there’s always tomorrow,” he said.

The rescue failure appeared to be a serious setback for NASA, which had billed the Endeavour voyage in part as a demonstration of the need for using human beings in space exploration.

The mission went awry just before 3 p.m. PDT, when astronaut Pierre J. Thuot, a Navy commander, made his first try at grabbing the 17-foot tall, 8,960-pound satellite. The attempt came as the Endeavour and the Intelsat 6 streaked over Central Africa at 17,500 miles an hour.

Tethered to the shuttle’s mobile robot arm, Thuot, 36, reached for the bottom of the slowly rotating satellite with a specially built 15-foot-long “capture bar.” But Thuot failed to secure the bar to the satellite and instead appeared to push its right side into a yaw.

“Oh, man,” Thuot said, “I hardly touched it.”

Over the next hour, three subsequent passes at the wobbling satellite also failed. At one point, astronaut Bruce E. Melnick, 42, working inside the shuttle at the controls of the robot arm, attempted to guide Thuot back under the Intelsat 6. During the maneuver, one of the astronauts on board the shuttle shouted a warning to Thuot: “Pierre, get out of there!”

The astronauts had been trying to pull the satellite inside the shuttle’s cargo bay, where they were to hitch it to a frame that houses a new 23,000-pound, solid-fuel rocket motor. The new motor is intended to boost the satellite out of its low Earth orbit so that it can be used to transmit telephone and television signals.

Stone, the mission operations director, said it does not appear that Thuot damaged the satellite during the rescue attempt. “We don’t know everything that happened, but I don’t expect we did any damage to the (Intelsat),” Stone said. “We’ll just have to wait and see.”

Stone said NASA engineers planned to work overnight, reviewing videotape of the failed rescue attempts and questioning the astronauts about what went wrong.

“It’s just a very difficult thing when you’re dealing with a great big piece of equipment and a long bar to get everything lined up,” Stone said.

The complex rescue operation, which began at 1:42 p.m. PDT, 225 miles over Australia, was to have been completed in just over five hours.

The Intelsat 6, which is scheduled to beam video of the 1992 Summer Olympics around the world, was stranded in its useless low orbit in March, 1990, when the commercial Titan rocket that carried it aloft malfunctioned.

In addition to the money it gave to NASA, Intelsat spent $50 million on the new rocket motor that the Endeavour astronauts were to have clamped onto the bottom of the communications satellite.

Intelsat controllers had been scheduled to fire the rocket motor Monday, which would have propelled the satellite into an elliptical orbit that would have pushed it as far as 51,750 miles away from the Earth. Eventually, the satellite was supposed to settle into a geosynchronous orbit--in effect, a stationary orbit--22,300 nautical miles (25,650 statute miles) over the Atlantic Ocean.

If it is eventually successful, the rescue would mark the first time that astronauts had saved a satellite by delivering a new rocket motor and attaching it in space.

The complex ballet that brought the 172,000-pound, 123-foot-long Endeavour and the Intelsat 6 together in space began at 4:40 p.m. PDT Thursday, when the new shuttle roared off on its maiden voyage from launch pad 39-B at the Kennedy Space Center in Florida.

Named after the ship that was the first command of Capt. James Cook, the 18th-Century British explorer, the $2-billion Endeavour was built by Rockwell International Corp. in Palmdale, Calif., to replace space shuttle Challenger. The Challenger was destroyed on Jan. 28, 1986, in an explosion that killed its seven crew members and stalled the Americans-in-space program for more than two years.

On Friday, Intelsat flight controllers at the consortium’s headquarters in Washington fired thrusters that began lowering the satellite’s orbit from 350 miles to the 225-mile altitude where it linked up with the shuttle.

They also slowed the spin of the satellite from 11 to less than 1 revolution per minute to allow Thuot to safely wrestle the satellite to a stop. Spinning the satellite helps maintain its stability in space, and reducing the spin increases the chance of yawing.

As the Intelsat team worked in Washington, the Endeavour crew and NASA flight officers at the Johnson Space Center in Houston began executing a series of shuttle thruster “burns” that brought the shuttle’s orbit into phase with the satellite’s flight path.

Endeavour closed in on the errant satellite shortly after 1:30 p.m. PDT as Thuot and astronaut Richard J. Hieb, 36, prepared for the first of the mission’s record three space walks.

At the same time, Intelsat controllers “safed” the satellite--locking its steering jets to prevent any errant thruster commands from Intelsat ground stations that could spell disaster for the rescue team.

At 1:42 p.m. PDT Thuot and Hieb emerged from the shuttle’s air lock into the cargo bay, where they began to unpack tools needed for the rescue.

Working from the shuttle’s aft cockpit, Endeavour commander Brandenstein took manual control of the shuttle’s thrusters as the spacecraft came abreast of the satellite, flying about 2,500 feet below the target.

Brandenstein slowly pulled the shuttle up in front of the satellite, with the shuttle’s tail pointed toward the Earth. The maneuver aligned the open shuttle cargo bay with the bottom of the Intelsat 6.

Thuot then tethered himself to the shuttle’s movable robot arm, visible on the ground through the cargo bay’s television cameras, and the problems began.

The mission’s other two scheduled spacewalks were to have taken place today and Tuesday, when astronauts were to have practiced techniques to be used on future missions to repair the flawed Hubble space telescope and to assemble the planned space station Freedom.

Space Rescue Planned The first flight of the new space shuttle Endeavour included an ambitious attempt to rescue the Intelsat 6 communications satellite, marooned in a low orbit since 1990. 1. Endeavour approaches Intelsat 6. Both spacecraft are moving at 17,500 m.p.h. relativeto Earth, but slowly relative to each other. 2. Astroaut Pierre J. Thuot clamps a control bar to the satallite so he can halt its rotation. 3. Astronauts mate the satallite to its new rocket motor and prepare it for ejection into space. Trapped in a useless orbit When it was launched in 1990, a booster failure marooned Intelsat 6 in a low orbit. The rocket attached by Endeavour’s crew will loft the satallite into a temporary orbit almost a quarter on the way to the moon. Finally, over a period of months, Intelsat 6 will be lowered into its correct, 22,300-mile-high orbit. Source: NASA