BEIJING, Sept. 16 -- It's a junkyard up in outer space and sometimes astronauts accidentally contribute to the litter.

In 1965, the first American spacewalker, Ed White, lost a spare glove when he went outside for the first time. From that time on, astronauts have accidentally contributed some of the more unusual of the 100,000 pieces of space trash that circle the Earth.

Last July, spacewalker Piers Sellers sheepishly reported losing a spatula. Nicknamed "spatsat" by space-junk watchers, it will return to Earth in a fireball early next month.

The Atlantis astronauts made their own contributions to the orbiting debris this week, as a couple of bolts escaped from the additional module they were connecting to the international space station.

To engineers, this isn't funny. Many of those pieces of space junk can kill astronauts, puncture satellites or, if nothing else, scratch up the space shuttle's expensive windows.

"It's one of these problems that is growing in seriousness," said William Ailor, director of the Center for Orbital and Re-entry Debris Studies at the Aerospace Corp in Los Angeles. "It's really the small things that will get you."

Using radar and telescope sensors, NASA and the Air Force track objects bigger than about 4 inches. The official "box score" of such space debris as of Thursday was 9,925. But the 90,000 smaller objects zipping around Earth at more than 15,000 mph can be just as dangerous and are harder to track.

Indeed, NASA even found debris composed of dried-up urine, toothpaste, and shaving cream all from space shuttle waste dumps in an experiment placed outside the Russian space station Mir, said officials at the agency's orbital debris program lab. An Indonesian satellite was once struck by urine and fecal matter.

NASA doesn't dump human waste outside much anymore.

Of all the items followed by the Air Force, the more unusual ones are those "that aren't necessarily meant to drop," said Air Force Space Protection Officer David Ward of the First Space Control Squadron in Cheyenne Mountain. "The astronauts didn't necessarily mean to let go of the bolts the last couple days, but that happens."

So when spacewalkers venture outside, NASA makes sure everything is tethered tools, bolts, the astronauts themselves. Think of it as wrapping a Christmas present with everything tied up to something, including the scissors and unused scraps of paper, said NASA spokesman Phil West, a former spacewalk tool engineer.

"You worry about (losing tools) all the time," said former astronaut and spacewalker Jay Apt, who noted that he had never lost anything.

And well they should worry. Not only can space junk damage or kill, but you can get sued, too.

A complex legal treaty governs who is responsible when the man-made debris cripples a satellite worth hundreds of millions of dollars, resulting in a special class of lawyers who monitor space junk, said Mark Matney, a scientist in the orbital debris program at Johnson Space Center. Enditem(Sources: China Daily)