The biggest conference on space debris has opened on Tuesday in Darmstadt, Germany. Scientists and decision-makers from the world's space-faring nations will meet at the 7th such get-together hosted by the European Space Agency (ESA) until Friday. Junk in space is a major and dangerous issue, as Holger Krag explains, who heads the Space Debris Office of ESA.
A fragment of debris the size of a bullet orbiting earth at a speed of approximately 25,000 mph has a devastating effect. "If it hits a satellite, it [the satellite] will be destroyed completely, because the particle possesses the power of a hand grenade," says Krag. There are thought to be 750,000 objects between 1 and 10 centimetres in size orbiting earth. Most junk is under a centimetre in diameter and orbits our planet at a height of 800 to 900 kilometres (500 to 550 miles).