Many spacecraft missions require stable, accurate line-of-sight pointing to microradians and below to accomplish their objectives. In order to maintain such precise pointing levels, the spacecraft design must minimize payload disturbances, either by maintaining a very quiet environment or by otherwise insulating the sensitive instrument from disturbances. A Lorentz force actuated isolator placed between the spacecraft bus and payload can effectively assist in stabilizing the payload's line of sight, both by isolating vibrations and by providing a smooth actuator for payload pointing control. Because the connection between the bus and payload is entirely determined by whatever wires need to cross the isolator gap, the physical connection can be very soft to non-existant, thus passively preventing the transmission of bus disturbances. With an attitude controlled payload, the bus and payload attitude controller designs become well separated. The bus controller requirements are reduced to pointing to within the isolator's range of motion and being capable of slewing the spacecraft with a rigidly attached payload. Consequently, both the bus and payload attitude controllers can be designed with standard techniques. Additional isolotor suite control is needed to damp and center relative translation. The attitude control on bus and payload decouples relative translation and rotation at the isolotor gap, and thus the isolator controller can use SISO design techniques to treat each translation degree of freedom separately. For the example remote sensing mission, transmissibility from bus ground footprint motion to payload ground footprint motion is attenuated by at least 40 dB at all frequencies, and the isolator average power draw during a slew is on the order of 20 Watts.
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