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Ultra-high resolution color images of the surface of comet 67P acquired by ROLIS

Schröder, S.E. and Mottola, S. and Arnold, Gabriele and Grothues, H.-G. and Hamm, Maximilian and Jaumann, R. and Michaelis, Harald and Pelivan, Ivanka and Proffe, G. and Bibring, J. P. (2015) Ultra-high resolution color images of the surface of comet 67P acquired by ROLIS. EGU, 12.-17. Apr. 2015, Wien, Österreich.

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Abstract

On Nov 12, 2014, the Rosetta Philae lander descended towards comet 67P/Churyumov-Gerasimenko. The onboard ROLIS camera successfully acquired high resolution images of the surface looking down from its vantage point on the instrument platform. ROLIS is a compact CCD imager with a 1024×1024 pixel sensor and a 57 ◦ field of view (Mottola etal., 2007, SSR128, 241). It isequipped with aninfinity lens (IFL),without which the camera focus is 30 cm. At Philae’s final landing site, ROLIS removed the IFL and initiated an imaging sequence that shows the surface at the highest resolution ever obtained for a cometary surface (∼0.5 mm per pixel). Illumination of the scene was provided by an onboard array of LEDs in four different colors: red, green, blue, and near-IR. ROLIS acquired one image for each color and a single dark exposure. The images show a unique, almost fractal morphology for the surface below the landing site that defies easy interpretation. However, there are similarities with some structures seen by the CIVA camera. Color and albedo variations over the surface are minor, and individual grains cannot be distinguished. The images are out-of-focus, indicating the surface was further away than the nominal 30 cm. The location of the illumination spot and the change of focus over the image are consistent with an inclined surface, indicating that Philae’s final resting position is strongly tilted. In fact, it was inclined so much that we see the local horizon, even though ROLIS is downward-looking. Remarkably, the scene beyond the horizon is illuminated by the Sun, and out-of-focus particles can be seen to travel in the sky. The images suggest the environment of the lander is laden with fine dust, but a final assessment requires careful consideration of possible sources of stray light. Just before Philae went to sleep, ROLIS acquired an additional exposure with the IFL and the red LED. The resulting image is fully in focus. Because Philae had rotated and lifted prior to acquisition, the last image allows us to reconstruct the scene below the lander in 3D. In case Philae wakes up from its slumber in the spring of this year, ROLIS should be able to resume operation. It may acquire additional well-focused images in all colors to better characterize the cometary environment and search for changes.

Item URL in elib:https://elib.dlr.de/101442/
Document Type:Conference or Workshop Item (Speech)
Title:Ultra-high resolution color images of the surface of comet 67P acquired by ROLIS
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Schröder, S.E.stefanus.schroeder (at) dlr.deUNSPECIFIED
Mottola, S.stefano.mottola (at) dlr.deUNSPECIFIED
Arnold, GabrieleGabriele.Arnold (at) dlr.deUNSPECIFIED
Grothues, H.-G.HG.grothues (at) dlr.deUNSPECIFIED
Hamm, Maximilianmaximilian.hamm (at) dlr.deUNSPECIFIED
Jaumann, R.ralf.jaumann (at) dlr.deUNSPECIFIED
Michaelis, Haraldharald.michaelis (at) dlr.deUNSPECIFIED
Pelivan, Ivankaivanka.pelivan (at) dlr.deUNSPECIFIED
Proffe, G.German Aerospace Center (DLR), Institute of Planetary Research, Berlin, GermanyUNSPECIFIED
Bibring, J. P.Institut d’Astrophisique Spatiale, Orsay, FranceUNSPECIFIED
Date:2015
Refereed publication:No
Open Access:No
In DOAJ:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:Comet
Event Title:EGU
Event Location:Wien, Österreich
Event Type:international Conference
Event Dates:12.-17. Apr. 2015
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Science and Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Erforschung des Weltraums
DLR - Research theme (Project):R - Projekt ROSETTA Lander
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Asteroids and Comets
Institute of Planetary Research > Planetary Geology
Institute of Planetary Research > Leitungsbereich PF
Institute of Planetary Research > Planetary Sensor Systems
Deposited By: Schröder, Dr. Stefan
Deposited On:05 Jan 2016 13:37
Last Modified:05 Jan 2016 13:37

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