A few summitry subjects never get raised in superpower chats in the Oval Office, such as the issue of man-made garbage floating in space. Yet, as the Cold War thaws, it is more likely that an American will be killed by Soviet space trash than by a nuclear weapon.

Some 6,700 pieces of large junk, including obsolete satellites, and billions of pieces of small junk, including paint flecks, are orbiting the Earth. If they don't kill someone when they fall to the Earth, then they pose a significant threat to astronauts. At 17,500 miles an hour, even a paint fleck can be fatal to a space-walker.

Without the flare of arms-reduction talks, U.S. and Soviet officials are quietly conducting junk-reduction talks. The first meeting was held last December without any public announcement.

The most intriguing aspect of these private talks is that neither the White House nor the State Department took the initiative. The National Aeronautics and Space Administration is handling the agreement in hopes of keeping politics out of it.

NASA has struck a preliminary working agreement with the European Space Agency, which has been leaving thousands of pieces of debris in space from its Ariane rockets.

The North American Aerospace Defense Command, or NORAD, in Colorado has counted more than 20,000 major pieces of junk since the Soviets launched Sputnik in 1957. Most of it has burned up or fallen to Earth. But the remaining pieces are potentially deadly to humans and a costly hazard to working satellites. NORAD has to keep close tabs on the junk so it isn't mistaken for hostile missiles.

Beyond the trackable pieces, there are literally billions of other specks of debris traveling at high speed in low Earth orbit. At least three, and possibly more catastrophic collisions have occurred in recent space history, destroying U.S. and Soviet satellites.

The floating garbage includes a glove lost by astronaut Ed White in his 1965 space walk. Astronaut Mike Collins inadvertently created the first "Swedish satellite" when he lost his grip on a Hasselblad camera during a space walk in 1966.

Much of the floating trash loses its orbit and burns up on re-entry. Only the biggest chunks pose a hazard to Earth. The largest single piece of junk to fall from the sky was the 82-ton Skylab in 1979. It broke into sizable chunks that rained over Australia and the South Pacific. The Soviet Cosmos space station sprinkled over Canada in 1978.

It's tough to stop the scattering of paint fragments burned off spacecraft by the sun, but NASA officials are determined to stop the deliberate littering of space.

In the late 1960s and 1970s, the Soviets were testing anti-satellite weapons, which they deliberately blew up in space, producing hundreds of pieces of floating shrapnel. Between 1975 and 1983, the Soviets exploded 11 surveillance satellites. The United States can take the blame for debris from at least nine second stages of Delta rockets, which accidently blew up three years after they were left in space.

The NASA negotiators may even address the sensitive subject of the Soviet's throwaway mentality. The cosmonauts have a habit of tossing trash bags out of their Mir space station.