Tomorrow's Buck Rogerses should keep their heads low: The heavens are fast filling with "space debris."
For years, space scientists have fretted about the growing litter problem in Earth orbit. We've launched thousands of satellites, spacecraft and rocket boosters since the late 1950s, and much of it is still up there, zipping along at several miles per second."A piece of debris about the size and weight of a softball can shatter a satellite if it hits the right spot," says a new study, "Orbital Debris," published this month by the National Academy of Sciences.
And what if that "softball" hits NASA's planned space station? If you thought the 1986 Challenger explosion hurt the space agency's image, just imagine what will happen if debris clobbers the station, kills a couple of astronauts and hurls their bodies into space.
True, space debris eventually falls back to Earth. Yet the problem isn't getting better, and for a surprising physical reason. The "debris cloud" is self-propagating. "Even if all launches were to cease, collisions between existing space objects would cause a gradual but exponential increase in the number of objects in orbit," says a summary of the academy's 210-page report.
Worse, most debris is invisible on radar. "In geostationary orbit 35,000 kilometers (23,000 miles) above the Earth - a particularly valuable orbit occupied by many communication and weather satellites - only objects larger than one meter (3 feet) across can be tracked and cataloged (by radar)."
For more scary details, those with computer access to the World Wide Web can call up a summary of the academy report at this Web address: http://www.nas.edu.
- Keay Davidson