PHILAE Localization from CONSERT / ROSETTA Measurement.

Abstract:

On 12 November 2014 at 15:34 UTC, after a 7-hour descent, the Philae lander made contact with the surface of the comet Churyumov-Gerasimenko (67P/CG) in the centre of the intended landing zone. Following the failure of its anchoring systems, it bounced and continued on its course. A couple of hours later, telemetry transmitted to Rosetta showed that Philae was stabilized on the surface and working properly although its final location was and still is not known.

From the morning of 13 November 2014, CONSERT data enabled an initial estimate to be made of Philae’s location based on signals propagated through the 67P/CG nucleus. This rough location was then refined by the triangulation method through three sets of measurements carried out during periods of direct visibility between Rosetta and Philae during the Philae’s First Science Sequence (FSS) on 13 and 14 November, . This paper presents these measurements, the accuracy of the propagation delay measurements and the derivation of the estimate of the localization of Philae taking into account the orbitography of Rosetta and the shape model of the comet.