主播大秀

Pieces of exploded and defunct satellites and spent rockets are orbiting earth, moving as fast as seven kilometres per second, and there's no imminent plan to get rid of them. Nasa scientist and astrophysicist Donald Kessler tells us about the risk these objects pose to future launches. Wing Commander Allen Antrobus of the Royal Air Force and the UK Space Agency outlines options for their removal, and Elizabeth Quintana, director of military sciences at the Royal United Services Institute, shines a geopolitical light on the problem.

(Picture: Artist's impression (not to scale) of low earth orbit debris released in 2011 by the European Space Agency)