Rosetta scientists choose site for first landing on a comet

The intended landing site for Philae, part of the Rosetta mission.

ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Today, the operators of the European Space Agency's Rosetta mission announced that they have chosen a site on Comet 67P/Churyumov–Gerasimenko for the first attempt to land human hardware on a comet. If the two-lobed shape of Churyumov–Gerasimenko is viewed as a rubber duckie (and many have made that comparison), the landing site is on the top of its head. If technical issues pop up as preparations for landing continue, an alternate site called C on the comet's body will be used.

The scientists making the decision had to balance a number of factors when picking a site. The lander, called Philae, will make an unpowered descent to the comet's surface, meaning it can't be maneuvered around any obstacles like boulders and ridges as it's approaching. The landing site also has to allow Philae's solar panels to regularly refill its batteries and for its communications gear to have ready contact with Rosetta.

Then there are the scientific issues. You want the probe to land somewhere where it will have access to pristine cometary materials and be close to sites that are likely to start venting the comet's tail as it approaches the sun. Rosetta will use radio transmissions sent through the comet by Philae to probe its interior.