The Soviet Union launched the very first earth-orbiting satellite in 1957, and the world looked on in awe as Sputnik flashed through the sky. Fifty years later, you’d be lucky to see anything. The U.S. Space Surveillance Network says there are almost 20,000 man-made objects in orbit, ninety-four percent of which are non-functional debris. And that’s not counting the hundreds of thousands of bits of junk too small to track. Little wonder the Defense Advanced Research Projects Agency (DARPA) has put out a call for someone – anyone – to come up with a way to effectively remove orbital debris.

The problem is, of course, that all that rubbish makes it hard for anything to safely navigate through a low-earth orbit. There are about nine hundred operational satellites that are in constant danger of smashing into things. And this problem was brutally highlighted in February this year when a derelict Russian spacecraft collided with a working communications satellite, adding about 500 more pieces of garbage to avoid in space.

The danger has been accelerating in recent years, with DARPA estimating that, since January 2007, there’s been a fifty percent increase in cataloged objects. (A good 2,000 of those, mind you, were caused by the Chinese government testing out an anti-satellite missile weapon on a weather satellite in that very month.) With the reality of space tourism drawing ever closer, the need to clean up around the earth has never been more pressing.

DARPA’s Request for Information (RFI) is extremely broad, and deliberately vague. The agency is requesting “technical approaches for cost effective and innovative system concepts for the removal of space debris.” So, basically, they just want good ideas.

There have been lots of ideas in the past but none, obviously, has struck DARPA as quite right. In 1996, NASA proposed “Project Orion”, a concept to zap space debris with lasers from earth. In 2003, the Aerospace Corporation proposed an inflatable set of “space tongs” that could grab and tow objects. And we recently reported on a “space sail” which would sweep rubbish away like a broom.

So, if you’ve got a concept for the removal of space debris, it might be worth submitting – and it certainly won’t be any more ludicrous than some of the suggestions DARPA has considered in the past. You’ll find the RFI here. But, hurry – you have to get your brilliant idea to them before the end of October.