Litterers in space

It seems that bad habits on Earth carry out into space, where there are all kinds of litterbugs. Space junk is flying around up there everywhere, some of it potentially dangerous. Things zip around at speeds something like 15,000 mph once they get into orbit.

A recent Associated Press report on the subject noted the first American spacewalker, Ed White, lost a spare glove once he stepped outside the ship. In July, spacewalker Piers Sellers lost a spatula. (Huh? Must be some $250 million NASA research project on whether bacon is crisper outside the stratosphere.) A couple of bolts escaped recently during a small construction job the Atlantis astronauts were performing on the international space station. The cosmonauts on the Russian space station Mir once simply threw bags of trash overboard.

In all, NASA and the Air Force have identified 9,925 man-made objects bigger than 4 inches orbiting the Earth. There's even more smaller debris. There's no space garbage truck collecting this stuff on a weekly basis, waking the astronauts up with a loud beep-beep-beep while backing up at 7 a.m. No outer space ordinance has been enacted making recycling mandatory.

"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."

The concern is that space shuttles and satellites will be damaged, or maybe even a ship containing some cute E.T. or baby Superman trying to make it to Earth.

Don't look up!

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On its Web site, www.reentrynews.com, the Aerospace Corp. lists all kinds of space hardware to fall from the sky since 1960. It almost makes Wisconsin seem like some kind of Bermuda triangle of space junk perpetually raining on unsuspecting cheeseheads in autumn as they prepare to tailgate for a Packers game:

"In September 1962, a cylindrical metal piece (diameter 0.15m, mass 9.5kg) fell on a street intersection in Manitowoc, Wisconsin," which was later identified as part of Soviet Sputnik IV.

"In October 1966 a titanium spherical pressure vessel (diameter 0.37m, mass 13.6kg) was found near Tomahawk, Wisconsin," eventually identified as "Soviet in origin."

Neither Moon, Pa., nor Mars, Pa., made the list of debris shower sites, but the falling pieces of propellant tanks, stainless steel skins, truncated cone metal and composite combustion chambers descended on such hot spots as Broken Hill in New South Wales, Australia; the Rio Negro District of Brazil; the Gandaki Zone of Nepal; Ostersound, Sweden; and Marie Galante, Martinique. There were no reports of anyone being injured, but in January 1997, "a lightweight fragment of charred woven material" struck a woman in Turley, Okla. And in March 2002, a titanium pressure sphere struck a home in Kasambya, Uganda.

If you've ever been struck by anything made out of titanium, you know that it smarts. Good thing that Oklahoma woman only felt the force of that woven material.

What are the chances?

The Aerospace Corp. folks would like to reassure you that you're safe from space junk. "The risk that an individual will be hit and injured is estimated to be less than one in one trillion," they say. "Re-entry risk estimates are supported by the fact that, over the last 40 years, more than 1,400 metric tons of materials are believed to have survived re-entry with no reported casualties."

OK, so one in a trillion is way less than the likelihood of getting struck by lightning (one in 1.4 million). But why do I keep getting this feeling that I'm the "one"? And notice they refer to "reported" casualties. What if there's some nomadic tribesman who was out hunting on his own one day and got splattered by a titanium spherical pressure vessel? Proper reporting methods for such incidents seem sorely lacking. For all we know, the chances of death by space junk are but one in 100 billion.

A bigger concern

None of that is to diminish something worth far more worry: the prospect of a doomsday asteroid striking the Earth. We've all seen it in movies by now, especially bad ones. (Ben Affleck saves the world! Hooray!)

Scientists of stature have concurred that the dinosaurs perished because of an asteroid slam some 65 million years ago. There's probably someone quietly running some computer model right now that says such devastation can occur about, oh, once every 65 million years. If that's the case, quit worrying about eating too many sweets or not exercising enough. Just enjoy life while you can.

An asteroid exploded on June 30, 1908, in the air above Tunguska, Siberia. It was only 55 yards in diameter, but flattened more than 575 square miles of forest. (And you thought the Route 65 landslide was a mess.) Scientists estimated in 2002 that a hit of that magnitude probably will occur once every 1,000 years, which was quite a relief to our great-great-great-grandchildren. The prior estimate figured it would happen once every 200 to 300 years.

"Every one of the craters on the moon is due to one of these impacts," David Morrison, who headed NASA's detection committee, told a Knight-Ridder reporter. "The events are very infrequent, but the consequences are very bad. You don't expect your house to burn down, but you can't afford to lose it. And that's the way I feel about civilization."