The Philae lander, part of the Rosetta mission to investigate comet 67P/Churyumov-Gerasimenko, was delivered to the cometary surface in November 2014. Here we report the precise circumstances of the multiple landings of Philae, including the bouncing trajectory and rebound parameters, based on engineering data in conjunction with operational instrument data. These data also provide information on the mechanical properties (strength and layering) of the comet surface. The first touchdown site, Agilkia, appears to have a granular soft surface (with a compressive strength of 1 kilopascal) at least ~20 cm thick, possibly on top of a more rigid layer. The final landing site, Abydos, has a hard surface.

https://science.sciencemag.org/content/sci/349/6247/aaa9816.full.pdf

The landing(s) of Philae and inferences about comet surface mechanical properties

Rosetta Lander - Landing and operations on comet 67P/Churyumov-Gerasimenko

https://elib.dlr.de/93332/1/LandingPrep_Ulamec_2015.pdf

Rosetta Lander – Philae: Landing preparations☆

ROSETTA lander Philae: Touch-down reconstruction

Rosetta lander Philae – Landing performance and touchdown safety assessment

The comet lander Philae (as part of Europe’s Rosetta mission) is en route to its target, 67/P Churyumov-Gerasimenko. With landing operations coming up at the end of 2014, a partial retesting of the Philae lander’s touchdown system was carried out in spring of 2013. Intensive testing was performed as part of Philae’s design and verification program approximately 10 years ago. However, the new test series specifically addresses touchdown conditions that have been out of capability of the pendulum test facility used at those times. Thus, the follow-up tests focus on touchdown conditions such as asymmetric loads, effects from terrain undulation, and the effect of granular soil mechanics, which could not be studied sufficiently in the original tests. This paper provides insight into the touchdown system of the Philae lander, the characteristics of the used test facility, its weight offloading operating mode, and the specific application to a small-body landing test. The results of the study are presented and d...

Silvio Schroeder

Papers

Experimental Investigations of the Comet Lander Philae Touchdown Dynamics