The facts

Space debris is trash, junk or garbage.  It includes derelict spacecraft, pieces of launch vehicles, remains from explosions, rocket motors, bolts, defunct satellites and fragments from any of the above.

Little pieces can mean big problems in space.  They travel 30 times faster than a commercial jet aircraft.  A fragment as small as 1 centimeter can significantly damage an operational satellite in orbit. 

Since debris can stay in orbit for decades, it accumulates around Earth in what could be likened to a space mine field.  There are currently 150 million pieces of orbital debris at all altitudes in space, according to the Union of Concerned Scientists.   

Satellites provide many services to those on land, including television, cell phone and GPS signals, weather forecasting, global environment monitoring, and views of our solar system.  Damage can result in loss of signals and valuable information.

The threat

A 2006 study by NASA estimates that large debris will increase by nearly 40 percent over the next 200 years, and the number of fragments will triple, even assuming no further objects are launched. 

As space debris accumulates around Earth, portions of space and entire orbital paths may become too dangerous and thus off-limits.  “Once you put debris (in space), the lifetime can be so long that you are taking a large band of space and reducing utility,” said David Wright, co-director and senior scientist with the Union of Concerned Scientists.

National security

In January 2007, China launched a missile against one of its own defunct satellites, the Feng Yun 1C (FY-1C) polar orbit weather satellite launched in 1999.  The destroyed satellite created more than 1,600 pieces of new space debris, according to the U.S. Space Surveillance Network.

The test also demonstrated China’s ability to target and blow up American military and communication satellites.  The United States logged a diplomatic protest in response.  "We are aware of it and we are concerned, and we made it known," White House spokesman Tony Snow said in a statement at the time.  Canada, Australia and Japan also registered protests.

Aside from the threat to the 400 operational U.S. owned satellites in orbit, the Chinese missile test increased the potential for catastrophic space collisions significantly.  According to an October 2007 report in Physics Today, Wright predicts that the debris from the Chinese missile test will increase satellite malfunction probability by 50 percent over the next decade.

“Speeds in orbit are very high; that’s why collisions can be so dangerous even with small objects,” said Wright.  “The concern is that if you have weapons that destroy satellites, you create tremendous amounts of debris.  That’s the reason why as we look ahead to multiple such tests, you’re talking about overwhelming amounts of space debris.”

International guidelines

Space debris has been a growing concern for decades.  NASA and the Department of Defense released debris-mitigation guidelines in the 1990’s, and Russia, Japan, France and the European Space Agency soon followed suit.  Standard practices for mitigating space debris include designing spacecraft to minimize debris released during normal operations, and limiting the risk to other space systems from accidental explosions.

There is currently no international treaty on space debris, but leading space agencies have formed the Inter-Agency Space Debris Coordination Committee (IADC) to address orbital debris issues.  The scientific and security communities have also discussed steps to legally restrict testing of weapons that destroy satellites in orbit, a measure Wright calls an “international priority.” 

“I think it’s inevitable that countries are going to have to look at this kind of thing,” said Wright.  “People used to think that space was so big that it didn’t matter what we did.  If we want to continue to use space, we need to think collectively of how the world uses it.”

- As originally reported on Medill News Service, January 30, 2008