The British-led mission to test techniques to clear up space junk has demonstrated a harpoon in orbit. The RemoveDebris satellite fired the projectile into a target board held at a distance on the end of a boom. Video of the event shows the miniature spear fly straight and true, and with such force that it actually breaks the target structure. But, importantly, the harpoon's barbs deploy and hold on to the board, preventing it from floating away. Prof Guglielmo Aglietti, from the University of Surrey in Guildford, is the principal investigator on the mission.

A UK-led experiment to tackle space junk has been sent into orbit. It takes the form of a small satellite that will practise techniques for tracking debris and capturing it. The RemoveDebris system is heading to the International Space Station where astronauts are expected to set the experiment running in late May. Space junk is an ever-growing problem with more than 7,500 tonnes of redundant hardware now thought to be circling the Earth. Ranging from old rocket bodies and defunct spacecraft through to screws and even flecks of paint - this material poses a collision hazard to operational missions.

After six years in space, China's first orbital station, the Tiangong-1 (aka the "Heavenly Palace") has finally outlived its operational limits and begun its descent back to Earth. It's expected to re-enter the atmosphere in a few months, whereupon a majority of the 9.3-ton station should burn up before reaching the surface. This is how defunct satellites are supposed to be disposed of. Unfortunately, until very recently, that hasn't often been the case. For the past 50 years, we've been filling Low Earth Orbit with defunct satellites, launch vehicle upper stages, and various bits of broken spacecraft (including frozen water, coolant and paint flecks).