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Shape and rotational elements of comet 67P/ Churyumov-Gerasimenko derived by stereo-photogrammetric analysis of OSIRIS NAC image data

Preusker, Frank and Scholten, Frank and Matz, Klaus-Dieter and Roatsch, Thomas and Willner, Konrad and Hviid, Stubbe and Knollenberg, Jörg and Kührt, Ekkehard and Sierks, Holger (2015) Shape and rotational elements of comet 67P/ Churyumov-Gerasimenko derived by stereo-photogrammetric analysis of OSIRIS NAC image data. EGU General Assembly, 12-17 Apr 2015, Vienna, Austria.

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Official URL: http://meetingorganizer.copernicus.org/EGU2015/EGU2015-11357-2.pdf

Abstract

The European Space Agency’s Rosetta spacecraft is equipped with the OSIRIS imaging system which consists of a wide-angle and a narrow-angle camera (WAC and NAC). After the approach phase, Rosetta was inserted into a descent trajectory of comet 67P/Churyumov-Gerasimenko (C-G) in early August 2014. Until early September, OSIRIS acquired several hundred NAC images of C-G’s surface at different scales (from ~5 m/pixel during approach to ~0.9 m/pixel during descent). In that one month observation period, the surface was imaged several times within different mapping sequences. With the comet’s rotation period of ~12.4 h and the low spacecraft velocity (< 1 m/s), the entire NAC dataset provides multiple NAC stereo coverage, adequate for stereo-photogrammetric (SPG) analysis towards the derivation of 3D surface models. We constrained the OSIRIS NAC images with our stereo requirements (15 deg < stereo angles < 45 deg, incidence angles < 85 deg, emission angles < 45 deg, differences in illumination < 10 deg, scale better than 5 m/pixel) and extracted about 220 NAC images that provide at least triple stereo image coverage for the entire illuminated surface in about 250 independent multi-stereo image combinations. For each image combination we determined tie points by multi-image matching in order to set-up a 3D control network and a dense surface point cloud for the precise reconstruction of C-G’s shape. The control point network defines the input for a stereo-photogrammetric least squares adjustment. Based on the statistical analysis of adjustments we first refined C-G’s rotational state (pole orientation and rotational period) and its behavior over time. Based upon this description of the orientation of C-G’s body-fixed reference frame, we derived corrections for the nominal navigation data (pointing and position) within a final stereo-photogrammetric block adjustment where the mean 3D point accuracy of more than 100 million surface points has been improved from ~10 m to the sub-meter range. We finally applied point filtering and interpolation techniques to these surface 3D points and show the resulting SPG-based 3D surface model with a lateral sampling rate of about 2 m.

Item URL in elib:https://elib.dlr.de/101362/
Document Type:Conference or Workshop Item (Poster)
Title:Shape and rotational elements of comet 67P/ Churyumov-Gerasimenko derived by stereo-photogrammetric analysis of OSIRIS NAC image data
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Preusker, Frankfrank.preusker (at) dlr.deUNSPECIFIED
Scholten, Frankfrank.scholten (at) dlr.deUNSPECIFIED
Matz, Klaus-Dieterklaus-dieter.matz (at) dlr.deUNSPECIFIED
Roatsch, Thomasthomas.roatsch (at) dlr.deUNSPECIFIED
Willner, Konradkonrad.willner (at) dlr.deUNSPECIFIED
Hviid, Stubbestubbe.hviid (at) dlr.deUNSPECIFIED
Knollenberg, Jörgjoerg.knollenberg (at) dlr.deUNSPECIFIED
Kührt, Ekkehardekkehard.kuehrt (at) dlr.deUNSPECIFIED
Sierks, HolgerMax-Planck-Institut für SonnensystemforschungUNSPECIFIED
Date:2015
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:Rosetta, 67P, Shape
Event Title:EGU General Assembly
Event Location:Vienna, Austria
Event Type:international Conference
Event Dates:12-17 Apr 2015
Organizer:European Geosciences Union
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 Instrumente
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Planetary Geodesy
Institute of Planetary Research > Planetary Geology
Institute of Planetary Research > Asteroids and Comets
Deposited By: Scholten, Dipl.-Ing. Frank
Deposited On:05 Jan 2016 13:07
Last Modified:31 Jul 2019 19:58

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