Why hasn Galileos innovative dual-spin design been used by newer missions (e.g. Cassini, MGS, MPF)?
Unlike previous planetary spacecraft, Galileo features an innovative “dual spin” design: part of the orbiter rotates constantly at three revolutions per minute, and part of the spacecraft remains fixed in inertial space. This means that the orbiter can easily accomodate magnetospheric experiments (which need to take measurements while rapidly sweeping about) while also providing stability and a fixed orientation for cameras and other sensors. The spin rate can be increased to 10 revolutions per minute for additional stability during major propulsive maneuvers. Mars Global Surveyor (MGS) is a planet mapping mission; the cameras and instruments in general take data of the surface of Mars, so there is no need for a spinning section of the spacecraft. “Fields and particles” (including magnetospheres), are the investigations that benefit from a spinning spacecraft. So MGS and Pathfinder (which is a Mars lander/rover mission) would not benefit from a dual-spin design. Cassini, on the other h
