Tracked Debris Orbiting Earth Photo by NASA

All the politicians and military strategists were buzzing about China’s missile test in January 2007, where the country blew up one of its old satellites in orbit. After the debates about the diplomatic and militaristic implications of this demonstration had settled down, scientists took the opportunity to get on their soapboxes and complain about the real problem with China’s missile test, the fact that it put between 500 and 800 pieces of junk into Earth’s orbit.

Each bit of space trash orbiting our planet is a potential hazard to satellites and future space travelers. The U.S. Space Surveillance Network currently tracks 13,000 pieces of space junk larger than four inches in diameter. This includes more than 2,000 spent rocket stages. Every time we launch something into orbit, we produce more space trash. There have been about 4,000 launches worldwide since the dawn of space flight.

Space is junk-filled enough without our adding to the mix. The NASA Spaceguard programs is currently tracking 2,700 Near Earth Objects (NEOs), and adding more to the list every day. 700 of these are at least half a mile wide, big enough to cause global climate catastrophe were one to hit Earth.

The Chicxulub crater in the Yucatan region of Mexico is the likely candidate for the asteroid that killed off the dinosaurs and 70 percent of all life on Earth. Some scientists theorize the impact vaporized carbonate rocks, releasing massive quantities of carbon dioxide into the atmosphere, and generating a dramatic greenhouse effect that shifted temperatures as much as 10 degrees. Other’s theorize the asteroid put enough dust and smoke into the atmosphere to block out the sun for up to six months, long enough to kill off most plant life and doom the entire food chain of animals relying on them. Whatever the mechanism, the impact was a climate shattering experience for planet Earth and traumatic to all life here.

Six months after a repair mission to the Hubble telescope corrected the satellite’s focus, the human race was treated to the incredible sight of comet Shoemaker-Levy 9 colliding with Jupiter. The train of over twenty fragments produced a trail of black smudges in Jupiter’s atmosphere. When you consider the fact that 1300 Earths can fit inside this largest planet in our solar system, those smudges start to resemble bug splats on a windshield, as in that’s what would happen to our home world.

Impact Scars in Jupiter’s Atmosphere Photo by NASA

Luckily, we have Jupiter’s magnificent mass to serve as the clean sweep for our solar system. Some scientists wonder if highly evolved life is even possible in solar systems that lack giant planets like Jupiter to reduce the amount of large debris floating throughout them.

But having Jupiter doesn’t mean we can lower our guard. In addition to tracking NEO’s, scientists are formulating plans for how to deal with an asteroid on collision course with Earth, should we find one. Missiles are ineffective, because they would simply produce more debris; however, asteroid tugboats, solar sails, and attaching rocket boosters to asteroids are just some of the options we have on the table for nudging these rocks just enough to pass us by.

The ability to escape off-world is another possibility, but only so long as we keep the space surrounding our planet free of debris. In April 1994, the space shuttle Endeavour took a ding on its window measuring a half-inch in diameter. This was caused by an orbiting paint chip. Anything much larger might have destroyed the shuttle and its crew, generating even more space debris.

There is now so much junk orbiting our planet that some scientists fear we have reached a critical mass, and that collisions are now inevitable. Each collision would generate more debris, which generates more collisions, and a chain reaction occurs that fills our orbit with so much trash it would not only prevent us from venturing into space for a very long time, but also destroy weather and communications satellites with all the benefits they bring us as well.

So while the Pentagon assures us no space debris poses a threat from their recent shoot-down of our own satellite, we do need to worry that the U.S. and China’s military demonstrations could bring about escalating weapons technologies in space, where even a small war would ground all humans on Earth for centuries.