Asteroid perturbations and the possible determination of asteroid masses through the ASTROD space mission

ASTROD (Astrodynamical Space Test of Relativity using Optical Devices) Miss ion Concept uses drag-free spacecraft in solar orbits to combine high-preci sion measurement of relativistic effects, measurement of solar angular mome ntum via Lense-Thirring effect, improvement in the measurement of G and the detection of low-frequency gravitational waves in a single mission. As a s imple implementation, two spacecraft in separable solar orbits are consider ed. These drag-free spacecraft will experience gravitational perturbations of the asteroids. This will limit the accuracy of the G measurement, and th e accuracy of determining the orbit elements and secular relativistic effec ts. However, from these perturbations, the masses of larger asteroids can a lso be determined. In this preliminary analysis, we use the present mass es timation of Ceres, Pallas and Vesta to calculate the perturbations of the s pacecraft. (C) 1999 Elsevier Science Ltd. All rights reserved.