The Putative Mechanical Strength Of Comet Surface Material Applied To Landing On A Comet

Paper number

IAC-07-A3.5.03

Author

Dr. Jens Biele, Deutsches Zentrum fur Luft und Raumfahrt e.V. (DLR), Germany

Coauthor

Dr. Stephan Ulamec, German Aerospace Center (DLR), Germany

Coauthor

Mr. Lutz Richter, Deutsches Zentrum fur Luft und Raumfahrt e.V. (DLR), Germany

Coauthor

Dr. Jörg Knollenberg, German Aerospace Center (DLR), Germany

Coauthor

Dr. Ekkehard Kührt, German Aerospace Center (DLR), Germany

Coauthor

Prof. Diedrich Möhlmann, German Aerospace Center (DLR), Germany

Year

2007

Abstract

The comet Lander PHILAE (of ESA’s mission ROSETTA) is going to land on comet 67P/Churyumov-Gerasimenko in 2014. Landing depends critically on the mechanical strength of the surface material: in an extremely soft material, the Lander (100 kg, 1 m/s touchdown velocity) will sink in too deep for successful operation while on a very hard surface the probability for bouncing and overturning increases. 
It is shown that direct knowledge on the strength of cometary surface material is very limited. In our view, even the Deep Impact experiment could not provide a reliable value of the mechanical strength of comet Tempel 1. 
Here we revise the ideas on cometary surface strength and theories that describe the low-velocity (~1 m/s) impact of blunt bodies into dust-rich, fluffy cometary materials. Available direct and indirect measurements and data are critically reviewed. Laboratory measurements and preliminary analysis are presented as well. Conclusions for Philae are drawn: most likely, the landing will be soft with a typical penetration of the Lander’s feet of up to 20 cm. 

Abstract document

IAC-07-A3.5.03.pdf

Manuscript document

IAC-07-A3.5.03.pdf (🔒 authorized access only).

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