image: SONC (green) and ESOC (blue) reconstructed trajectories in the comet-fixed frame from two observation angles. Note that plotting a 3-D trajectory in the rotating frame may give the impression that the collision at 16:20 has deflected the trajectory considerably, whereas in reality the comet has rotated (29deg/h) as well. If the WAC observations (red dots) were indeed the lander, then the trajectory would be clearly higher, as indicated by ESOC reconstruction. Before the collision, the two reconstructions are very close. SONC trajectory includes a third touchdown, which however is unconstrained except for its time. Shape model used for this figure: RMOC version 5. This material relates to a paper that appeared in the July 31, 2015 issue of Science, published by AAAS. The paper, by J. Biele at German Aerospace Center (DLR) in Cologne, Germany, and colleagues was titled, "The landing(s) of Philae and inferences about comet surface mechanical properties." view more
Credit: [Credit: ESA/ESOC/SONC]