The Philae lander at work on Comet 67P/Churyumov-Gerasimenko. While Rosetta studies the comet from close orbit, Philae will obtain measurements from the surface.
Immediately after touchdown in November 2014, a harpoon will be fired to anchor the lander and prevent it from escaping the comet’s extremely weak gravity. The minimum targeted mission time for Philae is one week, but surface operations may continue for many months. The measurements from the Rosetta orbiter will last from August 2014 to the end of 2015.