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Mechanical Properties of Cometary Surfaces

Biele, Jens und Vincent, Jean-Baptiste und Knollenberg, Jörg (2022) Mechanical Properties of Cometary Surfaces. Universe, 8 (487). Multidisciplinary Digital Publishing Institute (MDPI). doi: 10.3390/universe8090487. ISSN 2218-1997.

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Offizielle URL: https://www.mdpi.com/2218-1997/8/9/487

Kurzfassung

Mechanical properties, in particular, strength (tensile, shear, compressive) and porosity, are important parameters for understanding the evolution and activity of comets. However, they are notoriously difficult to measure. Unfortunately, neither Deep Impact nor other comet observations prior to Rosetta provided firm data on the strength of cometary material. This changed with the Rosetta mission and its detailed close observation data and with the landing(s) of Philae in 2014. There are already many articles and reviews in the literature that derive or compile many different strength values from various Rosetta and Philae data. In this paper, we attempt to provide an overview of the available direct and indirect data; we focus on comet Churyumov–Gerasimenko/67P but include a discussion on the Deep Impact strength results. As a prerequisite, we start by giving precise definitions of ‘strength’, discuss soil mechanics based on the Mohr–Coulomb ‘law’ of micro-gravity, and discuss bulk density and porosity, sintering, and the physics of the strength of a cohesive granular medium. We proceed by discussing the scaling of strength with the size and strain rate, which is needed to understand the observational data. We show how measured elastic properties and thermal (conductivity) data can be correlated with strength. Finally, a singular very high strength value is reviewed as well as some particularly small-strength values inferred from the bouncing motion of Philae, data from its collisions with the surface of the comet, and scratch marks it left, allegedly, on the surface close to its final resting site. The synthesis is presented as an overview figure of the tensile and compressive strength of cometary matter as a function of the size scale; conclusions about the size dependence and apparent natural variability of strength are drawn.

elib-URL des Eintrags:https://elib.dlr.de/188315/
Dokumentart:Zeitschriftenbeitrag
Titel:Mechanical Properties of Cometary Surfaces
Autoren:
AutorenInstitution oder E-Mail-AdresseAutoren-ORCID-iDORCID Put Code
Biele, JensJens.Biele (at) dlr.dehttps://orcid.org/0000-0002-7414-829XNICHT SPEZIFIZIERT
Vincent, Jean-BaptisteJean-Baptiste.Vincent (at) dlr.dehttps://orcid.org/0000-0001-6575-3079NICHT SPEZIFIZIERT
Knollenberg, JörgJoerg.Knollenberg (at) dlr.deNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Datum:15 September 2022
Erschienen in:Universe
Referierte Publikation:Ja
Open Access:Ja
Gold Open Access:Ja
In SCOPUS:Ja
In ISI Web of Science:Ja
Band:8
DOI:10.3390/universe8090487
Verlag:Multidisciplinary Digital Publishing Institute (MDPI)
ISSN:2218-1997
Status:veröffentlicht
Stichwörter:comets, mechanical properties, strength, density, porosity, Churyumov–Gerasimenko, 67P
HGF - Forschungsbereich:Luftfahrt, Raumfahrt und Verkehr
HGF - Programm:Raumfahrt
HGF - Programmthema:Erforschung des Weltraums
DLR - Schwerpunkt:Raumfahrt
DLR - Forschungsgebiet:R EW - Erforschung des Weltraums
DLR - Teilgebiet (Projekt, Vorhaben):R - Exploration des Sonnensystems
Standort: Berlin-Adlershof , Köln-Porz
Institute & Einrichtungen:Raumflugbetrieb und Astronautentraining > Nutzerzentrum für Weltraumexperimente (MUSC)
Institut für Planetenforschung > Planetengeodäsie
Institut für Planetenforschung > Planetenphysik
Hinterlegt von: Herrmann, Astrid
Hinterlegt am:16 Sep 2022 13:51
Letzte Änderung:29 Mär 2023 00:02

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