How to park on a comet

摘要

We're there, now where do we put the spacecraft? The European Space Agency's Rosetta probe has been scanning comet 67P/Churyumov-Gerasimenko for sites where its Philae lander could touch down in November. The shortlist is now down to five. "It's a good compromise," says Philae manager Stephan Ulamec. The team has chosen three spots, labelled B, I and J, on the comet's "head", and two on the "body", A and C (see picture). The letters come from the original list of 10 sites and do not indicate order of preference. Light levels, visibility from Rosetta and surface conditions all influenced the selection, but no one site is perfect.