GG: the s/c around the accelerometer (II)

Largest disturbance due to residual air drag: 108 times smaller than 1g…but 108 times larger than target signal….. Þ Partial drag compensation (FEEP thrusters) & partial CMR (Common Mode Rejection)

Equatorial orbit easier (no regression of the nodes, stays perpendicular to s/c spin axis…) but sun-synchronous orbit much less expensive to reach (from high latitude russian launchers….)