一艘欧洲无人飞船将与彗星会合

A space probe that has been racing across the solar system to catch up with a comet for a decade will finally reach its historic destination Wednesday.

The European Space Agency's Rosetta spacecraft will rendezvous with the Comet 67P/Churymov-Gerasimenko after a final set of maneuvers that will place it in an orbit about 100 kilometers above the comet's surface.  If successful, the $1.7 billion Rosetta will become the first spacecraft to rendezvous with a comet. 

Once it reaches orbit, Rosetta will escort Comet 67P for the next year and observe it as it heads towards the sun.  The highlight of the mission will come in November, when Rosetta will release a small probe that will land on Comet 67P -- the first ever spacecraft to accomplish such a feat.