* Astronomy

Using a tether system devised by MIT researchers, astronauts could one day stroll across the surface of small asteroids, collecting samples and otherwise exploring these rocks in space without floating away.
The ability to visit asteroids could also be invaluable for testing equipment for a mission to Mars by humans. Further, knowing how to tether an asteroid could be helpful if one needs to be towed away from a potential collision course with Earth, says Christopher Carr, a postdoctoral associate in MIT's Department of Earth, Atmospheric and Planetary Sciences.
Carr and Ian Garrick-Bethell, a graduate student in the department, describe their system in an upcoming issue of the journal Acta Astronautica.
Walking on an asteroid is much more difficult than walking on a planet because asteroids have so little gravity. An astronaut who tried to step onto one would likely fly off or hover above the surface.
Now Carr and Garrick-Bethell say that tying a lightweight rope completely around an asteroid could solve that problem. Once the rope was in place, astronauts could attach themselves to it and manoeuvre or possibly even walk along the surface.

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