CRISIS IN SPACE; MIR COLLISION CASTS DOUBT ON STATION'S FUTURE.

Byline: Marcia Dunn Associated Press 

In the worst space collision ever, an unmanned cargo ship crashed into Russia's Mir station Wednesday, rupturing the pressurized vessel, knocking out half the power and raising questions anew of how long the decrepit spacecraft can function before someone gets killed.

The American and two Russians on Mir were said to be in no immediate danger, but it was unclear how much longer they could remain on board. Mir has an attached Soyuz capsule that can bring the crewmen home in an emergency.

The men were forced to work in darkness with much of their equipment turned off to save energy. Unless more power is restored soon - how soon, the National Aeronautics and Space Administration couldn't say - they may not be able to operate their life-support systems, such as the primary oxygen generators and the carbon dioxide removal system.

``It's a serious situation,'' said astronaut Jerry Linenger, who returned from Mir in May after battling a fire and other life-threatening problems aboard the aging, 11-year-old outpost. ``Fire aboard a spacecraft and decompression are the two most dangerous things that can happen on an orbiting vehicle.''

The collision put an estimated one-inch gash in Spektr, Mir's laboratory module. When the crew heard the hissing of oxygen seeping through the hole and felt pressure dropping throughout Mir, they immediately shut the hatch, sealing Spektr off from the rest of the space station but exposing it to the deadly vacuum of space.

While still trying to determine the extent of the damage, NASA said it will rethink its program of sending astronauts to Mir.

``Once we get the situation stabilized and understand what the long-term potential for operation on the Mir is and what its capabilities remaining are, then we will evaluate with the Russians where we go next,'' said Frank Culbertson, director of NASA's shuttle-Mir program. ``We might at some point want to terminate the mission.''

Even before Wednesday's accident, some experts and Washington officials had argued that Mir was too old and worn out to inhabit safely.

Mir's past problems

In February, a defective oxygen generator sparked a 14-minute fire that sent chunks of molten metal flying. In the weeks afterward, the cooling system leaked, oxygen generators failed and the carbon dioxide removal system broke down.

The collision happened as the Russian cosmonauts practiced docking the Progress supply ship by remote control. Commander Vasily Tsibliyev could not slow the ship, and it slammed into Spektr, Culbertson said.

Pressure aboard the rest of the space station soon stabilized. As of Wednesday afternoon, eight hours after the accident, the pressure was slightly low and equivalent to an altitude on Earth of 2,500 feet, Culbertson said. The temperature was about normal, he added.

Through their quick action, the cosmonauts saved the station from worse damage and possible abandonment, both countries' space programs said.

The crash also punctured one of the solar panels on Spektr and dented a radiator, Culbertson said. Spacewalks almost certainly would be required to repair the hole, if it can be fixed, he said.

The laboratory module is equipped with four electricity-producing solar panels, none of which is working now, and contains much of American astronaut Michael Foale's belongings, including his bed, clothes and half his science research. Many of his experiments were probably ruined.

President Clinton was receiving frequent updates from NASA and said through his spokesman, Mike McCurry, that he remained committed to the shuttle-Mir program.

Abandon space ship?

James Oberg, an expert on Russian space affairs, said the collision is just the latest example of why Mir should be abandoned as soon as possible.

``I've always felt that the Mir safety is certainly declining with age, while the utility of our being there has been also declining,'' he said.

The accident knocked the station away from the ideal sun angle for the remaining solar panels to keep charging, Culbertson said. The crew will have to use precious fuel to fire thrusters to turn the station in the right direction.

To conserve oxygen and power, Foale, Tsibliyev and Alexander Lazutkin were ordered to turn off as much station equipment as possible and to move slowly.

``I'm sure over the next week they're going to keep the lights down low,'' Linenger said. ``But I think generally the crew will be in kind of a slow-down mode and try not to generate or rev up your metabolism very much.''

The Progress supply ship, filled with garbage, orbited at a safe distance from Mir and was expected to plunge through the atmosphere and burn up in a day or two. It was supposed to be jettisoned this weekend anyway.

Russian space officials said they do not know what went wrong; the Progress ship wasn't even close to its docking port when it slammed into Mir.

Near miss

Another Progress ship almost hit the station three months ago, during a similar docking test while Linenger was aboard. Although spacecraft have bumped against Mir before, none has caused any significant damage, officials said.

Viktor Blagov, a deputy director of the Russian Mission Control near Moscow, said the modular structure of Mir saved it. The 100-ton-plus station resembles a giant cross: six large modules and one small shuttle docking port are linked, each with its own hatch.

``It worked like a ship, which can keep afloat if one compartment is damaged,'' Blagov said.

Culbertson stressed that the accident was unrelated to Mir's age. The station is 11 years old, six years beyond its original expected lifetime. The Spektr module was just two years old.

``This decompression that occurred could have happened on Day 1 of the Mir's life,'' he said.

Foale, who replaced Linenger in May, is the fifth of seven Americans who are supposed to live on Mir to help NASA gain experience for the future international space station. Shuttle Atlantis isn't due back at Mir until September; it's supposed to take up Foale's replacement and more supplies.

CAPTION(S):

2 Photos, box

PHOTO (1) Mir space station

(2 -- color) Frank Culbertson, Phase One Space Shuttle-Mir program manager, left, and astronaut Jerry Linenger discuss the collision.

Associated Press

BOX: The trouble with Mir