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Gravity field determination of a Comet Nucleus: Rosetta at P/Wirtanen

Pätzold, M. and Häusler, B. and Wennmacher, A. and Aksnes, K. and Anderson, J. D. and Asmar, S. W. and Barriot, J.-P. and Boehnhardt, H. and Eidel, W. and Neubauer, F. M. and Olsen, O. and Schmitt, J. and Schwinger, J. and Thomas, N. (2001) Gravity field determination of a Comet Nucleus: Rosetta at P/Wirtanen. Astronomy & Astrophysics, 375 (2). pp. 651-660. ISSN 0004-6361. doi:10.1051/0004-6361:20010829.

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One of the prime objectives of the Rosetta Radio Science Investigations (RSI) experiment is the determination of the mass, the bulk density and the low degree and order gravity of the nucleus of comet P/Wirtanen, the target object of the international Rosetta mission. The RSI experiment will use the spacecraft's radio carrier frequencies at X-band (8.4 GHz) and S-band (2.3 GHz) in order to measure slight changes of the orbit velocity via the classical Doppler effect induced by the gravity attraction of the comet nucleus. Based on an estimate of the background Doppler noise, it is expected that a mass determination (assuming a representative radius of 700 m and a bulk density of 500 kg/m^3) at an accuracy of 0.1% can be achieved if the spacecraft's orbit is iteratively reduced below 7 km altitude. The gravity field of degree and order two can be detected for reasonable tracking times below 5 km altitude. The major competing forces acting on the spacecraft are the radiation pressure and the gas mass flux from cometary activity. While the radiation pressure may be predicted, it is recommended to begin a gravity mapping campaign well before the onset of outgassing activity (>3.25 AU heliocentric distance). Radial acceleration by water outgassing is larger by orders of magnitude than the accelerations from the low degree and order gravity field and will mask the contributions from the gravity field.

Item Type:Article
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Asmar, S. W.0000-0002-9912-645X
Additional Information:© 2001 ESO. Received: 18 May 2001. Accepted: 7 June 2001. The RSI experiment is funded by the Deutsches Zentrum für Luft- und Raumfahrt (DLR), Bonn, Germany, under grants 50QP9709 and 50QP9717, by Norges forskningsraad, Norway, under project No. 136028/431, and by the National Aeronautics and Space Administration (NASA), Washington, USA.
Funding AgencyGrant Number
Deutsches Zentrum für Luft- und Raumfahrt (DLR)50QP9709
Deutsches Zentrum für Luft- und Raumfahrt (DLR)50QP9717
Norges forskningsraad136028/431
Subject Keywords:techniques: radar astronomy - space vehicles - comets: individual: 46 P/Wirtanen - comets: general
Issue or Number:2
Record Number:CaltechAUTHORS:20180307-101131542
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Official Citation:Gravity field determination of a Comet Nucleus: Rosetta at P/Wirtanen M. Pätzold, B. Häusler, A. Wennmacher, K. Aksnes, J. D. Anderson, S. W. Asmar, J.-P. Barriot, H. Boehnhardt, W. Eidel, F. M. Neubauer, O. Olsen, J. Schmitt, J. Schwinger and N. Thomas A&A, 375 2 (2001) 651-660 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85175
Deposited By: Ruth Sustaita
Deposited On:07 Mar 2018 18:30
Last Modified:15 Nov 2021 20:26

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