Crew Plans First-Ever 3-Man Spacewalk : Shuttle: Astronauts will leave Endeavour, seek to grab errant satellite with gloved hands in third daring rescue attempt.

After two days of failure, the crew of the space shuttle Endeavour plans a daring third attempt today to rescue a marooned communications satellite by having astronauts literally grab the huge, spinning spacecraft with their gloved hands.

The plan, developed Tuesday by the seven-member Endeavour crew and NASA flight officers, calls for the first three-astronaut spacewalk in history. The final rescue effort is scheduled to begin about 2 p.m. PDT, and could last as long as eight hours.

“We think to do this sufficiently effectively and successfully, we probably need three folks out there,” Endeavor commander Daniel C. Brandenstein, 49, told flight controllers at the National Aeronautics and Space Administration’s Johnson Space Center.

The maneuver could pose hazards for the $2-billion Endeavour, the $150-million satellite and the astronauts, who would act as human springs keeping the 17-foot-tall, 8,960-pound Intelsat 6 from crashing into the orbiter. Brandenstein must fly the Endeavour to within eight to 10 feet of the satellite for the rescue to succeed.

Nevertheless, NASA mission operations director Randy Stone said, “We are confident that we’ve got a safe operation. . . . We’re going to capture the satellite and we’re going to force this piece of gear into place.”

The International Telecommunications Satellite Organization, the 122-nation consortium that owns and operates the satellite, paid NASA $93 million for the so-far unsuccessful rescue mission. Intelsat does not have a money-back guarantee.

The Endeavour made at least 14 unsuccessful passes at the Intelsat 6 on Sunday and Monday as the two spacecraft flew in tandem 225 miles above the Earth. The astronauts were unable to grab the satellite and attach the new rocket motor, which is to boost Intelsat 6 to its proper orbit 22,300 nautical miles above the Earth.

The original plan called for astronaut Pierre J. Thuot, 36, to hang from the end of the shuttle’s 50-foot robot arm, grab the satellite with a 15-foot “capture bar” and bring it inside the shuttle’s cargo bay. But he was unable to snag it, and on Sunday knocked it into a wild gyration that prevented further rescue attempts that day.

Later, Thuot told NASA flight controllers the problem seemed to be that the satellite could not sustain the force required to fire locking latches without spinning out of control.

Calvin Seaman, the NASA engineer who designed the tool, said Tuesday the key problem was that Intelsat and Hughes Aircraft Co. of El Segundo, Calif., which manufactured the satellite, provided NASA with incorrect information on the satellite’s sensitivity to motion.

However, mission director Stone said everyone involved in the planning shared the blame.

Intelsat 6 was stranded in a useless low-Earth orbit in March, 1990, when the commercial Titan rocket that carried it aloft malfunctioned.

The satellite, which can simultaneously transmit 120,000 telephone channels and three television feeds, is expected to earn Intelsat more than $750 million over its 10-year life.

The plan worked out Tuesday, and rehearsed underwater in NASA’s Houston test facility, involves spacewalks by astronauts Thuot and Air Force Lt. Col. Thomas D. Akers, 40, and Richard J. Hieb, 36.

As he has during the previous rescue attempts, Thuot will stand in stirrups on a small platform at the end of the shuttle’s robot arm. Hieb will stand in a foot restraint attached to the starboard side of the shuttle’s open cargo bay.

Akers will stand in another foot restraint affixed to a triangular strut structure in the cargo bay.

As the Endeavour closes in on the massive satellite, the three astronauts literally will reach up and grab three electric motor housings that each are about the size of a soup can.

Holding on to the satellite with one hand, Hieb will reach down and grab one end of the capture bar, passing the other end to Akers. Together, with the satellite stopped and stabilized, they each will use one hand to position the bar on the satellite’s metal ring until the latches pop into place.

If they succeed, the astronauts then will revert to the earlier plan, and clamp the satellite to the frame that houses the rocket motor. At the end of the exercise, they will eject the assembly into space using four, pre-loaded springs.

NASA officials announced Tuesday that they plan to extend Endeavour’s flight by one day, aiming for a landing Friday at Edwards Air Force Base in California.