Swiss Review 4/2018

14 Swiss Review / July 2018 / No.4 Science SIMON GSTEIGER The two domes that stand on concrete pillars in Zimmerwald in the canton of Berne look like part of the set for a science fictionmovie. Youmight think youwere on theMoon or Mars were it not for the luscious green Zimmer- wald meadows, the neighbouring farm, the humof a tractor and the Alps in the background. The canton and University of Berne have recently equipped and expanded the nearby Zimmerwald Observatory. There are now three new telescopes in both domed buildings. Scientists are using them to scour outer space for debris. This is an urgent requirement, ac- cording to Thomas Schildknecht, Di- rector of the Zimmerwald Observa- tory: “It’s hard to imagine how much damage these fragments can cause.” They move at a speed of over 7.5 kilo- metres a second. “That’s almost ten times faster than a bullet,” he says. At that speed even the smallest pieces re- lease as much energy as the explosion of a hand grenade upon impact. An es- timated 30,000 objects are circling Earth, and these are just the larger ones. Permanent monitoring One of the new instruments consists of two wide-field telescopes. They have an extensive field of vision and are used to permanently monitor de- bris in the geostationary ring. This ring is at an altitude of 36,000 kilo- metres, where weather and commu- nications satellites orbit. “The tele- scopes allowus to seewhen something is moving against the backdrop of the stars. We then log what’s in motion,” explains the Zimmerwald Director. Various recordings enable an object’s orbit to be calculated. This helps to es- tablishwhether it is a previously iden- tified or newly discovered object. “The amount of debris has reached a critical point and cannot continue to increase,” points out Schildknecht. The problem can be tackled at source once it is clear where the objects are coming from. They are often remnants of satellites or rockets, but sometimes also fragments of insulation panels. “The developers of spacecraft have to be notified so that they can modify construction methods,” he says. Debris ends up in “cemetery” A preventative approach is one solu- tion. However, if the amount of debris in outer space continues to rise, other strategies will be required. One possi- bility is robots able to gather debris. Such collection robots are neverthe- less controversial due to the risk of them being misused for military pur- poses. “Just imagine reconnaissance satellites being sabotaged,” says Schil- dknecht. Above a certain distance The hunt for debris in outer space Switzerland is at the very forefront of international research on outer space. It is now demonstrating its penchant for tidiness by becoming a debris hunter in outer space. The Zimmerwald Observatory has commissioned three new telescopes for this task. “It’s become crowded up there” Whereas it was just a few dozen satellites at the start of the history of space travel, there are now over 1,300 of them circling Earth’s orbit. “It’s become quite crowded up there in recent years,” reveals Thomas Schildknecht, Director of the Zimmerwald Observatory. It is not so much the active artificial celestial bod- ies that pose a problem but rather those which have exceeded their lifespan, such as decom- missioned satellites, fuel tanks and panels. Space debris is increasingly presenting issues for space travel. The orbits of around 30,000 such objects have now been identified. They also represent a threat to manned spacecraft. Anyone planning a mission in outer space is best advised to coordinate the operation with great precision. The organisations behind such launches rely on data logs indicating the or- bits of debris fragments. (SG) The two new domed buildings at the Zimmerwald Observatory are equipped with three telescopes.