At http://phys.org/print401090506.html … the Rosetta spacecraft was landed on the surface of comet Churyumov-Gerasimenko in September and effectively brought the mission to an end. We didn't hear a lot of what was revealed as it approached the surface at the time as Rosetta's onboard instruments were still working. The EPA scientists have been looking at some of the information beamed back …
… this image was taken 20m above the surface. The pressure of the gas outflow from the comet seemed to increase near the surface, but no activity was happening at the landing site. A last measurement of water vapour showed it was emitting two tablespoons per second. When the comet was nearer the Sun, and more active, this was at a rate of two bath tubs a second. That water comes from inside the comet it would appear. On the other hand the gas coma was still outgassing – even though it was a long way from the Sun. Magnetic field measurements, on the other hand, were in agreement with earlier findings. It seems the comet is a non-magnetic body.