Free Astronomy Magazine November-December 2016

SMALL BODIES position was unknown due to its dramatic landing which prematurely impaired its functionality. Putting an end to a mission that produced such a wealth of results was definitely a difficult but inevitable deci- sion. Besides the fact that because of the comet’s increasing distance, communica- tions with the probe would have turned out to be, month after month, more diffi- cult, such difficulties would have shortly become more marked due to the Sun near- ing the line-of-sight between Earth and the probe. Therefore, on the evening of 29 Septem- ber, mission operators initiated the pro- cedure for the final manoeuvre to set Ro- setta on a collision course with the comet. At the time of beginning its descent, there were just 19 km separating the probe and the comet. The region chosen for its con- trolled crash (occurred at about 1 metre per second) was Ma’at, on the smaller of the two lobes, not far from an area with active and particularly interesting pits about a hundred meters wide and half as deep. Since the final descent phase of- fered the possibility to study the gas and dust behaviour at an extremely close dis- T he top right image taken on 30 September shows a portion of the more flatter Ma’at region (image scale 17 cm/pixel) where Rosetta landed. Above, another view of the same region shot from an altitude of just under 6 km (image scale 11 cm/pixel). Right, one of Ma’at pits called Deir el-Medina, where the primeval cometesimals that formed the comet were detected (image scale 2.3 cm/pixel). [ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA]