Reconstructing Philae’s flight across the comet

Data from both the Philae lander and Rosetta orbiter experiments, as well as simulation results based on Philae’s mechanical design have been used to reconstruct the lander’s attitude and motion during its descent and touchdowns on Comet 67P/Churyumov-Gerasimenko on 12 November 2014.  A new animation was presented today, one year after Philae touched down on the comet, focusing on Philae’s dramatic two-hour flight from Agilkia to Abydos – in this blog post we hear from some of the people behind its production. Over the last year, more and more details about exactly what happened have been gleaned from a detailed evaluation of data from various instruments and sensors. These have provided an extensive account of the events from the moment Philae separated from Rosetta, through its seven-hour descent, and the subsequent two-hour flight across the surface that included three touchdowns and a collision. A numerical simulation of Philae, calibrated and verified with test data from a mock-up of the lander, was used to model its interaction with the surface at Agilkia. The subsequent free flight and later bounce dynamics were reconstructed from the trajectory in conjunction with attitude information derived from the ROMAP instrument. Together, these efforts made it possible to determine Philae’s behaviour on 12 November 2014 with sufficient accuracy to make this new visualisation. Philae’s first touchdown on the comet (TD1) at 15:35 UT is constrained by a very precise knowledge of its landing position and orientation based on ROLIS images, the times at which the three feet contacted the surface as measured by SESAME, the vertical dynamics from the damping tube housekeeping data, lander dynamics simulations explaining the footprints imaged later by OSIRIS, outbound attitude reconstructed from ROMAP and RPC-MAG data, and the outbound velocity vector based on a trajectory reconstruction. Felix Finke of DLR, one of […]

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