What happens to all the satellites and other pieces of technology that are left in space? Do they continue to orbit our plant, disintegrate or are broken into small pieces, fall to or collide with other planets, or What? Is this a problem to be considered in this millennium?

The problem of space debris is a serious one. In the past, old satellites, pieces of rockets, and astronaut trash were left in Earth orbit. Things near the earth (within a few hundred miles) re-enter the atmosphere fairly quickly (within a few years) because there is still a little air to slow them down at these low orbits.

However, things in higher orbit remain in orbit forever. Anything with motors on them tend to explode eventually, creating swarms on tiny debris. Even dust from meteors can hit satellites, knocking off chips of paint. Even a fleck of paint can do serious damage at 17,000 miles per hour!

These days, satellite manufacturers are becoming more conscious about de-orbiting satellites when they are finished being used. The best examples are the Iridium satellites, a series of satellites belonging to a failed communications company. Rather than stranding the satellites in space, Iridium and their partners are spending several million dollars to de-orbit the satellites.

Problems still exist with existing trash, and various schemes have been developed for finding ways to clean up space. In the meantime, radar is used to locate larger pieces of space junk (sizes of nuts and bolts or larger). The space shuttle must routinely make orbital corrections to avoid such junk. The International Space Station recently announced that the shielding on the newest Russian module is too thin, and that the module has a 25% chance of being punctured by space debris during the life of the space station. So, space trash is still a serious concern!

Thanks for writing!

Sincerely, Kurtis Williams