Orbiting Debris Trashing Space

Space is getting more and more crowded with orbiting debris, with the latest addition being the thousand pound tank of ammonia jettisoned by an astronaut, spacewalking while performing cleaning chores on the International Space Station. To avoid the object, controllers in Houston raised the space station’s orbit about five miles. Ordinarily such an object is not dumped in space, but a Johnson Space Center spokesman explained that the space shuttle had no room for transporting the tank back to the Earth. After about a year orbiting the planet, the object will reenter the Earth’s atmosphere and burn up.

Almost three weeks prior to the dumping of the tank of ammonia, controllers at Goddard Space Flight Center in Greenbelt, MD, were forced to take evasive action to avoid a hit on NASA’s CloudSat satellite by a small satellite launched in 2005 by Iran. The CloudSat’s engines were used to move it, putting over two miles between the two spacecrafts and averting a possible crash.

These events reveal the increasing problem of satellite and space junk orbiting the Earth. The number of objects has been steadily growing until early this year the federal catalog of detectable objects, which are at least four inches wide, orbiting the planet reached 10,000. Such objects include inactive satellites, old rocket engines, and assorted material resulting from explosions and weapons testing.

Adding to the total are the fragments left by the testing of an antisatellite weapon by the Chinese in January, and the breakup of four spacecraft in February, bringing the number of orbiting detectable objects to 12,000. There is increasing concern that an object hit by a piece of space debris could break into hundreds of fragments and start a chain reaction.

NASA’s $1.3 billion environmental Terra spacecraft was moved on June 22 to avoid the debris generated by the Chinese antisatellite test, with the debris coming about a half mile from the Terra. China’s test came on January 11 when an old weather satellite was destroyed, creating what scientists call the worst satellite fracture of the space age. On February 2, a new Chinese navigation satellite engine apparently failed, leaving it in pieces, and on February 14 an abandoned Russian engine blew up, possibly due to the explosion of the remaining fuel. On February 18, an old spacecraft developed by China and Brazil fragmented, perhaps because of a collision with other debris, and on February 19, a large Russian space tug blew up, again as a possible consequence of leftover fuel exploding. It has been noted that three of the four breakups could have been prevented with better designed and operated vehicles.