HR: 0830h
AN: G41B-0032    [PDF]
TI: Monitoring Mars LOD Variations from a High Altitude Circular Equatorial Orbit: Theory and Simulation
AU: Barriot, J
EM: jean-pierre.barriot@cnes.fr
AF: OMP/CNES, 14, Av. E. Belin, Toulouse, 31400 France
AU: * Dehant, V
EM: veroniq@oma.be
AF: ORB, 3, Av. Circulaire, Brussels, 1180 Belgium
AU: Duron, J
EM: julien.duron@oma.be
AF: ORB, 3, Av. Circulaire, Brussels, 1180 Belgium
AB: We compute the perturbations of a high altitude circular equatorial orbit of a martian probe under the influence of an annual variation of the martian lenght of day. For this purpose, we use the first order perturbations of the newtonian equations of motion, where the small parameter is given from the hourglass model of Chao and Rubincam, which allow a simple computation of CO2 exchanges during the martian year. We are able to demonstrate that the perturbations contains two components: the first one is a sine/cosine modulation at the orbit frequency, the second one is composed of terms of the form exp(t)*sin(t), so the orbit may not stable in the long term (several martian years), with perturbations growing exponentially. We give the full theory and numbers.
DE: 1227 Planetary geodesy and gravity (5420, 5714, 6019)
DE: 5409 Atmospheres--structure and dynamics
DE: 5417 Gravitational fields (1227)
DE: 5430 Interiors (8147)
SC: Geodesy [G]
MN: 2003 Fall Meeting