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 six degree of freedom 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-existent, thus passively preventing the transmission of bus disturbances. This paper outlines a straightforward design approach for the spacecraft control laws and presents simulation results for an example remote sensing mission. In particular, the bus attitude controller, payload attitude controller, and isolator controller are designed in sequence, using a simple single-input single-output methodology. For the example remote sensing mission, an isolation actuator was modeled on large gap Lorentz force isolators originally designed for a microgravity application. Even with a non-optimized actuator design, the 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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