大 Question / Are there missions where the absolute position of the center of mass of a cluster of spacecraft does not require control? Yes! In fact most of the ones we can think of Image construction u-v filling does not depend on absolute position Earth coverage As with single spacecraft, Gravity moves the mass center of the cluster as a whole, except for perturbations Disturbance(perturbation) rejection The effort to control perturbations affecting absolute cluster motion(such as J2) is much greater than that for relative motion Only disturbances affecting the relative positions(such as differential J2) NEED controlling to keep a cluster together Docking Docking is clearly a relative position enabled maneuver DIl EMFF Final review ug.29,2003DII EMFF Final Review Aug. 29, 2003 Question II: Question II: • Are there missions where the absolute position of the center of mass of a cluster of spacecraft does not require control? • Yes! In fact most of the ones we can think of… – Image construction • u-v filling does not depend on absolute position – Earth coverage • As with single spacecraft, Gravity moves the mass center of the cluster as a whole, except for perturbations… – Disturbance (perturbation) rejection • The effort to control perturbations affecting absolute cluster motion (such as J2) is much greater than that for relative motion • Only disturbances affecting the relative positions (such as differential J2) NEED controlling to keep a cluster together – Docking • Docking is clearly a relative position enabled maneuver