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The mass of Phobos
Author(s) -
Tolson R. H.,
Blackshear W. T.,
Mason M. L.,
Kelly G. M.
Publication year - 1977
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl004i012p00551
Subject(s) - spacecraft , orbiter , martian , data set , satellite , astrobiology , orbit (dynamics) , geodesy , physics , astronomy , remote sensing , geology , mars exploration program , aerospace engineering , statistics , mathematics , engineering
Radio tracking data associated with the February 1977 encounters between the Martian satellite Phobos and the Viking Orbiter I spacecraft have been analyzed to determine the gravitational constant (GM) of Phobos. A linear error analysis was conducted to determine the selection of data and the parameter solution set which would yield the best estimate of GM. This error analysis indicated that the optimal data set was a data arc beginning just prior to the closest encounter and spanning three consecutive spacecraft orbits; data near periapsis were deleted. The most feasible parameter solution set consisted of the Phobos GM and the spacecraft initial conditions. The result of the data analysis was an estimate of (7.3 ± 0.7) × 10 −4 km³/sec² for GM of Phobos.