Following a conference on space debris, the European Space Agency has warned that the amount of space junk floating around in orbit is a problem that needs to be dealt with 'urgently.' They are calling for a number of test missions to examine different methods of controlling or removing the debris. "Our understanding of the growing space debris problem can be compared with our understanding of the need to address Earth’s changing climate some 20 years ago," said Heiner Klinkrad, head of the agency's Space Debris office. A couple years ago we discussed an idea for de-orbiting space junk by hitting it with a laser to change its momentum. An Australian company has now received funding from NASA and the Australian government to try just that. "We've been developing tracking systems using lasers for some years, so we can actually track very small objects with a laser rangefinder to very high accuracy. ... If you allow that velocity to change over a period of perhaps 24 hours, then you can get actually a 100-meter shift in the location of an object to deflect it from colliding with another space debris object." Other plans are in development as well, and there currently exists an international guideline saying that new hardware must de-orbit and burn up in the atmosphere after 25 years of operation — but compliance is lagging. Meanwhile, collision events are becoming more common (PDF), and experts worry about the safety of the International Space Station and important satellites. "Their direct costs and the costs of losing them will by far exceed the cost of remedial activities."