With a hop, skip and a jump, the Rosetta Philae made its final soft landing on Comet 67P/Churyumov-Gerasimenko after 10 years of chasing down the comet. Following two jumps after the initial touchdown, Philae finally settled in a so-far unknown location below a cliff. Hours later the Rosetta spacecraft established connection with the lander and started transmitting data from Philae to Earth.
While the journey took a decade, Philae completed its primary mission in only 57 hours. What can one little lander accomplish in 57 hours, you ask? While it might appear to be just one instrument, the lander houses 12 separate experiments that come from all across Europe. Germany has a number of contributions as the German Aerospace Research Institute (DLR) is the lead on the project. Johannes Gutenberg-Universität contributed the APX instrument, an alps-p-X-ray spectrometer; and the Max-Planck-Institut für Sonnensystemforschung added COSAC, an evolved gas analyzer. MUPUS from the Institut für Planetenforschung is used to measurement subsurface and surface properties; and the ROLIS instrument for imaging is from the Deutsches Zentrum für Luft- und Raumfahr, which also contributed one of the SESAME instruments. The Max-Planck-Institut für Sonnensystemforschung and the lone Finish University, the Finnish Meteorological Institute, contributed two other SESAME instruments. SESAME stands for the Surface and Electric Sounding and Acoustic Monitoring Experiment, quite the mouthful. Each of the SESAME instruments focuses on something different, CASSE is the Comet Acoustic Surface Sounding Experiment; DIM is the Dust Impact Monitor; and PP is the Permittivity Probe – and that’s just the German contributions.
The panoramic images taken by Philea are from the CIVA instrument, the contribution of the Université Paris Sud of France. Also from France is the CONSERT instrument, used for radio sounding and nucleus tomography and built by the Institut de Planétologie et d’Astrophysique de Grenoble. Open University in the United Kingdom added the Ptolemy instrument, another evolved gas analyzer for isotopic composition. The ROMAP instrument is a magnetometer and plasma monitor, and comes from the Technische Universität in Germany and KFKI in Hungary. The last instrument, SD2, is a drill that is used for sample retrieval and is from Politecnico di Milano in Italy. While all this detail may be unnecessary, it gives a perspective of how much data can be collected and analyzed in 57 hours with 12 instruments.
Each instrument on Philae gathers important information about one facet of the comet, and altogether the data creates a much clearer picture of the composition of comets, something that has been mostly speculation until now. Initial observations leads scientists to believe that Philae landed on a surface that is harder then ice, since MUPUS was not able to drill more than a 10-20 cm into the surface. Combined with data collected by the Rosetta spacecraft, it is believed that below this hard surface the ice becomes more porous and less dense. With so much data in hand, the researchers have a lot work ahead of them and Philae has closed its doors and gone into hibernation. Philae will remain in hibernation until the comet gets closer to sun in September of 2015, at this point, attempts will be made to wake up the lander and gather more data.