Astronauts Test Equipment on 2nd Spacewalk

Grunting, puffing and giggling as they glided up and down the shuttle’s cargo bay, two astronauts tested several different contraptions Monday to determine which would be the most help to workers who are to assemble the space station later this decade.

What they may have proved during their marathon venture outside the Atlantis is that less may well be best.

Astronauts Jerry L. Ross, 43, and Jay Apt, 41, seemed to prefer the simplest of the three devices they tested along a 47-foot-long track they installed on the side of the cargo bay.

The National Aeronautics and Space Administration would like to know which of the vehicles would best serve astronauts of the future who will be required to make many trips along the station’s main truss, which will be longer than a football field. Sometimes they will have to carry loads so heavy they could not budge them on the ground.

One day after their unscheduled spacewalk during which they fixed a stuck antenna that threatened the $617-million Gamma Ray Observatory, Monday’s “extravehicular activity,” as NASA calls it, was sort of a joy ride.

“What a great way to travel,” Ross said as he glided along the rail. The Atlantis was passing 280 miles over Cuba, traveling at 17,300 m.p.h., as the two astronauts moved back and forth on their makeshift railroad at about the speed of a brisk walk.

Three different vehicles were used on the rail. One was simply a platform that the astronaut hooked his feet in and then pulled himself manually--hand over hand--along the rail. The second looked a little like a railway cart--the astronaut powered it by pushing a handle back and forth, cranking a mechanical ratchet drive. The third was powered by a motor with electricity generated by cranks turned by the astronaut.

“That’s fantastic,” Apt said after grunting and puffing to get the electric version moving. “There’s a fair amount of energy required for start-up,” he concluded.

“I prefer a less energetic requirement,” he said.

Both men seemed to prefer the hand-over-hand, manually propelled platform, and their conclusions will largely determine what system is eventually used, according to former astronaut Robert Overmyer, who is in charge of astronaut systems for one of the station’s prime contractors, McDonnell Douglas.

“We are really going to pick their brains,” Overmyer said, referring to the two astronauts. “They will be the deciding vote.”

Overmyer, a veteran of two shuttle missions, said that even what would seem to be a relatively simple task--opening and closing a hand--can be very tiring because of the constrictions of the spacesuit, he added.

“There is a lot of fatigue, particularly in the hands,” he said. “The glove wants to stay open.”

The pressurized suit tends to force the fingers flat, so when an astronaut clutches a tool he or she is fighting the suit. That contributes to crew fatigue, so NASA is anxious to provide some form of vehicle to ease the workload.

“We would prefer to keep it as simple as we can,” Overmyer said.

The astronauts also spent part of the day riding on the tip of the shuttle’s robotic arm to see how useful such a device might be during construction of the space station.

By the time Apt and Ross completed their assignments Monday they had chalked up two firsts: On Sunday, they made the first unscheduled spacewalk during which they fixed a satellite, and they also became the first astronauts to venture outside a shuttle on consecutive days.

And it probably would not be hard to get them to do it again. At one point Monday, Ross looked toward the Earth as the Florida Keys slipped past.

“Holy cow,” he said. “What a view.”

The Gamma Ray Observatory, deployed by the Atlantis on Sunday, is safely in orbit 280 miles above the Earth, and there were no reports of problems. A NASA official said the observatory’s four instruments will be turned on next week and the first scientific data could be coming back by the end of the month.

The Atlantis, commanded by Steven R. Nagel, 44, is scheduled to land Wednesday at 7:34 a.m. PDT, at Edwards Air Force Base in Southern California. The other members of the crew are Kenneth D. Cameron, 41, the pilot, and Linda M. Godwin, 38.