 | Willner K. The martian moon phobos: a geodetic analysis of its motion, orientation, shape, and physical parameters / Deutsches Zentrum für Luft- und Raumfahrt Institut für Planetenforschung, Berlin-Adlershof. - Köln: DLR, Bibliotheks- und Informationswesen, 2010. - 104 p. ill. - (Forschungsbericht; 10-13). - Bibliogr.: p.92-99. - ISSN 1434-8454
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Kurzfassung ..................................................... 1
Abstract ........................................................ 2
1 Motivation ................................................... 6
2 The Martian Moon Phobos ...................................... 8
2.1 The Origin .............................................. 8
2.2 The Orbit ............................................... 8
2.3 The Figure ............................................. 10
3 Missions to Mars ............................................ 12
3.1 Missions to Phobos and Deimos .......................... 12
3.2 Camera Systems of Different Space Missions ............. 14
3.2.1 The Viking Orbiter Cameras ...................... 14
3.2.2 The Mars Orbiter Camera ......................... 15
3.2.3 The High Resolution Stereo Camera ............... 16
3.2.4 The Super Resolution Channel .................... 17
4 Reference Systems and Tools ................................. 20
4.1 Time ................................................... 20
4.2 Reference Frames ....................................... 20
4.2.1 The Phobos Reference Flame ...................... 22
4.3 Surfaces and Maps ...................................... 24
4.4 Planetary Image Data ................................... 24
4.5 Software ............................................... 25
5 Astrometric Observations .................................... 27
5.1 Previous Astrometric Observations ...................... 27
5.2 Shadow Observations .................................... 28
5.2.1 Determination of the 3D - Coordinates ........... 31
5.2.2 Determination of Time ........................... 31
5.2.3 Stellar Coordinates of Phobos ................... 33
5.2.4 Reconstruction of the Shadow .................... 34
5.2.5 Results - Shadow Observations ................... 36
5.3 Fly-by Observations .................................... 37
5.3.1 Fly-by Images ................................... 37
5.3.2 Pointing Verification ........................... 38
5.3.3 Center of Mass Measurements ..................... 40
5.3.4 Results ......................................... 42
5.4 Validation of Orbit Models ............................. 43
5.5 Secondary Results ...................................... 45
6 Control Point Network on Phobos ............................. 47
6.1 Previous Control Networks .............................. 47
6.2 Determination of Control Point Coordinates ............. 48
6.2.1 Available Image Data ............................ 48
6.2.2 Point Measurements .............................. 50
6.2.3 Computation of Coordinates ...................... 51
6.2.4 Results ......................................... 52
7 Global Shape Model .......................................... 55
7.1 Global Digital Terrain Model ........................... 56
7.1.1 Improving the Orientation ....................... 57
7.1.2 Matching ........................................ 59
7.1.3 DTM Generation .................................. 62
7.1.4 Controlled Ortho-Image Mosaic and Global Map .... 65
7.2 Spherical Harmonic Function Model ...................... 66
7.2.1 Evaluation of the Data Set ...................... 67
7.2.2 Computation ..................................... 68
7.2.3 Interpretation of the Coefficients .............. 70
8 Physical Parameters of Phobos ............................... 72
8.1 Volume ................................................. 72
8.2 Bulk Density ........................................... 73
8.3 Moments of Inertia ..................................... 74
8.3.1 Theory .......................................... 74
8.3.2 Computation of the Tensor ....................... 75
8.4 Forced Libration Amplitude ............................. 77
8.4.1 Observation ..................................... 77
8.4.2 Modeling ........................................ 78
9 Discussion and Conclusions .................................. 81
9.1 Motion in the Orbit .................................... 81
9.2 Shape and Physical Parameters .......................... 82
9.3 Outlook ................................................ 85
List of Abbreviations .......................................... 86
List of Symbols ................................................ 87
List of Figures ................................................ 89
List of Tables ................................................. 91
Bibliography ................................................... 92
A Shadow Observations ........................................ 100
В Astrometric Observations ................................... 101
С Coefficients of the Spherical Expansion Model .............. 103
D Phobos Map ................................................. 104
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