Study: Nasa`s Planned Space Station Vulnerable To `Space Junk`

June 25, 1992|By Scripps Howard News Service.

WASHINGTON — The space station Freedom will face a 1-in-3 risk of a serious collision with ``space junk`` during its first 10 years in orbit unless officials make design changes, a new study warns.

Such a collision would involve damage to ``critical components`` of the station, those necessary for the crew`s survival and the station`s continued operation. Repairs could cost at least $2.2 billion.

The study criticizes the National Aeronautics and Space Administration for continuing with design work on the station without deciding how to protect it from collisions with space debris. The study was conducted by the U.S. General Accounting Office, a congressional agency.

NASA contractors have designed much of the station with ``obsolete`` data about the threat of collisions with space junk, according to the study.

Space debris consists of millions of objects from earlier space missions that litter the area around the Earth. It includes everything from flecks of paint and bits of metal to big chunks of rocket boosters and payloads.

Although much of the debris is small, speed makes it dangerous. The debris moves at relative velocities of 22,000 miles per hour. At that speed, a bit of aluminum the size of an aspirin tablet would strike a surface with the impact of a 400-pound safe going 60 m.p.h. Estimates indicate that at least 140,000 objects the size of an aspirin or larger are in orbit around Earth.

There are more than 3 million smaller objects in orbit.

And even these objects, such as paint flecks the size of the period at the end of this sentence, cause concern because they could pit and erode surfaces on space craft.

NASA in January told its contractors to incorporate into their designs newer, more accurate estimates of the risk from space debris. But contractors have not yet told NASA how much it will cost to improve the station`s resistance to collisions.

The study cites indications that incorporating the new risk estimates-through use of heavier shielding, for instance -would result in much higher than estimated costs and cause delays in building the station.

Assembly of the station, to be roughly the size of a football field, could begin as early as 1995 and be completed by the end of the century.

NASA is moving ahead with plans to complete ``critical design reviews``

for the station early next year without having a comprehensive debris protection strategy.

The study, however, urges NASA to make its safety decisions before approval of the final station design, even if that means delaying the start of the project.