Garbage in Orbit: Debris from 40 Years of Space Exploration Presents a Thorny Disposal Problem
Hayhurst, Chris, E Magazine
A two-ton Chinese spy satellite the size of a small car is headed for a crash landing somewhere on Earth. Although most satellites quickly burn up when they reenter Earth's atmosphere, this one is prepared for the fiery ride, and is deemed sufficiently armored to survive it. Launched from the Gobi Desert in October 1993, the spacecraft malfunctioned 10 days later. Since then it has been losing altitude, and is expected to drop from the sky in early April. Most likely it will plunge into the ocean, but other possible landing sites include many of the Earth's major cities and all of the continental United States.
Since the launch of the Soviet "Sputnik I" in 1957, over 4,500 spacecraft have been hurled from the Earth's surface, nearly half of which remain in orbit. According to the new book Orbital Debris: A Technical Assessment, only about 10 percent of these craft are still functional; the rest simply constitute space junk, very expensive garbage. But that's just the intentional debris. There are also many tons of "mission-related" garbage littering the solar system.
Among the useless junk released into space during a craft's deployment and operation are spent rocket bodies, lens caps, bolts, aluminum oxide particles from rocket motor exhausts, paint chips and fragmentary objects generated by more than 120 spacecraft and rocket body breakups.
Large debris at relatively high orbital altitudes is so stable it can perform loops around the Earth for millions of years. All told, there are trillions of projectiles, ranging from particles less than a millimeter in size to larger objects like the Chinese satellite. The U.S. Space Station in Colorado Springs keeps busy tracking and cataloging 8,000 of these objects, leaving the positions of more than a few others in doubt. The debris remains in orbit until retarding forces cause it to disintegrate in flames into the atmosphere or, as sometimes happens, it plunges back to Earth.
Astronauts have reason to worry about entering such a potentially lethal environment. A paint chip one millimeter in diameter traveling at 10 kilometers per second could easily tear a hole in a space suit. If the astronaut survives the impact, the resulting pressure loss is still very dangerous.
There's not nearly as much danger to the Earthbound. Nicholas Johnson, senior scientist at the Space Environment and Orbital Debris Resource Center at the Kaman Sciences Corporation in Colorado Springs, says, "Nearly 17,000 objects have reentered the atmosphere. …