Who controls space?

A collision between a satellite and a spacecraft highlights the need for traffic control in space.

Tom AbateMarch 11, 2009 15:53Updated May 30, 2010 11:47

A satellite in space, leaving the cargo bay of the Space Shuttle Discovery Nov. 1, 1998. Today, numerous satellites are in space, leading to fears of possible collisions. (NASA/Reuters)

SAN FRANCISCO — Every driver has occasionally heard the sharp thwack of a pebble bouncing off the car's windshield. But what is merely startling on the highway can be catastrophic in space, where clouds of debris — orbiting the Earth at thousands of miles per hour — have the momentum to destroy military and civilian communications satellites.

The danger posed by orbital debris was recently brought to the fore by the collision of a 1,980-pound decommissioned Russian military satellite and a 1,500-pound spacecraft belonging to the Iridium satellite phone network. The Feb. 10 crash — the first head-on debris collision in space — highlighted the absence of any effective governmental or corporate solutions to a problem that can only worsen as more nations and corporations venture into space.

The incident took place at an altitude of about 490 miles, in the heart of what is called Low Earth Orbit (LEO). This zone — which stretches from 100 to 1,000 miles above the surface — is ideal for satellite communications because its relative proximity to Earth shortens the amount of time it takes for signals to bounce from place to place. As a result, LEO has become increasingly crowded, and now contains more than 400 military and civilian satellites.

This week, in fact, a piece of debris forced the crew of the international space station to take shelter in its escape capsule, a rare close call for the orbiting platform.

In 1978, NASA scientist Donald J. Kessler theorized that each accident in LEO would create a cloud of space shrapnel, imperiling other satellites in a cascade effect now known as the Kessler Syndrome.

The Space Surveillance Network, part of the U.S. Strategic Command, is already tracking more than 18,000 pieces of space junk — from whole satellites, such as the Russian Cosmos craft, to fragments the size of a softball.

Shortly after the February collision, U.S. officials said they were “tracking 505 pieces from the Cosmos satellite and 194 pieces from the Iridium satellite in two separate debris clouds.” A senior Russian military space official reportedly said the crash sent new debris radiating out in orbits from 300 to 800 miles.