On September 10, the ESA spacecraft Rosetta finally entered a circular orbit around Comet 67P/Churyumov-Gerasimenko at a distance of 30 kilometers, after having traveled in a triangular pattern 50-100 kilometers from the nucleus since August 6.
A few days later, a decision was made regarding the primary landing site of Philae – area J was selected, placed on the top of the head of the comet nucleus, whose shape resembles that of a duck.
The region in question consists of irregular depressions and plateaus, covered by a fine powder. The surface here is relatively planar, contains few blocks, and is thus suitable for landing. However, it is still possible that unpleasant surprises awaits – on September 29 the distance from Rosetta to the comet is decreased to about 19 kilometers, and on October 10 to 10 kilometers, which means that the resolution of the camera OSIRIS will increase a factor three during the coming month. Therefore, we also monitor a secondary landing site – the reserve choice is area C.
Landing site C is located on the main body, roughly where the duck would have its tail. The area has many similarities with landing site J – it is covered by dust, has relatively few blocks, and consists of planar surfaces surrounded by circular flat-floored depressions. The final decision on landing site will be made on October 14.
The scientific imaging system OSIRIS was built by a consortium led by the Max Planck Institute for Solar System Research (Germany) in collaboration with CISAS, University of Padova (Italy), the Laboratoire d’Astrophysique de Marseille (France), the Instituto de Astrofísica de Andalucia, CSIC (Spain), the Scientific Support Office of the European Space Agency (The Netherlands), the Instituto Nacional de Técnica Aeroespacial (Spain), the Universidad Politéchnica de Madrid (Spain), the Department of Physics and Astronomy of Uppsala University (Sweden), and the Institute of Computer and Network Engineering of the TU Braunschweig (Germany). OSIRIS was financially supported by the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), and Sweden (SNSB) and the ESA Technical Directorate.