
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: WEDNESDAY, February 13, 1991                   TAG: 9102130516
SECTION: EDITORIAL                    PAGE: A-8   EDITION: METRO 
SOURCE: 
DATELINE:                                 LENGTH: Medium

JUNK IN SPACE/ EARTH ORBIT FILLED WITH HUMAN LITTER

LITTER IS usually just an eyesore, not a hazard. There's one place you're not likely even to see it, but where it's dangerous. That's in space.

Since 1957, when human beings began launching contraptions to spin around the Earth, they've also been leaving litter up there: spent rocket stages, dead satellites, screws, tools and countless thousands of other artifacts of earthly civilization. The throwaway mentality has gone into orbit.

A lot of technology creates debris. Some rocket stages fall into the sea and sink. Bombers that can't reach their targets jettison their ordnance rather than risk landing with it. Radioactive material is buried. That stuff is at least out of the way, posing no immediate hazard.

Orbiting junk is different. There are no landfills up there. Nothing biodegrades in space. Instead it takes up a path around the planet, traveling at thousands of miles an hour.

At such speeds, even tiny bits of trash can be dangerous to spacecraft - or to cosmonauts out for a stroll. If a fragment of aluminum one centimeter across collided with a spacecraft, it would carry the force of a 400-pound safe falling at 60 mph.

Fortunately, it would not necessarily have the same effect on what it hit. But as far back as 1983, the shuttle Challenger was struck by an orbiting object that pitted one of its 5/8-inch-thick windows. Later, bits of white paint were found in the tiny crater; and scientists calculated the shuttle had collided with a flake less than 0.01 inch in diameter, traveling at two to three miles a second.

Such collisions still are rare, but each one creates more junk that adds to the hazard. Some space specialists fear that low Earth orbit could become unusable as early as the end of this century.

Fortunately, the number of space litterers is limited, and they are being more tidy. American, Soviet, European, Japanese and other space programs try now to make sure their rocket stages are emptied of fuel and pressure while in orbit, so they will not explode. The U.S.S.R. no longer destroys its failed military satellites.

Still, it appears that something like a neatness-in-space treaty is needed, whereby industrial nations pledge not to litter Earth's atmosphere, and share related information and technology. The international lawyers can find the right language.

by CNB