Propulsive Attitude Control System on a Boom

The DoD is currently developing advanced deployable structures for applications such as large solar arrays, large radiators, deployable booms, and radar antenna structures. Reliable, low-mass deployment actuators are considered a significant technicalchallenge in each of these applications. Analysis of the guidance, navigation and control requirements also show these structures to generally require integrated propulsion to maintain attitude, pointing accuracy, or provide orbit transfer capabilityindependent of the host spacecraft.Responding to this need, Busek Co. Inc. teamed up with Composite Technology Development Inc. (CTD) to develop micropropulsion attitude control system (MPACS) integrated with a multifunctional elastic memory composite (EMC) deployable boom. Micro pulsedplasma thrusters (MPPT), integrated into MPACS cluster, offer 10-fold mass reduction relative to conventional ACS devices such as momentum wheels and torque rods and up to 1000 times greater pointing accuracy. Placing the MPACS on a deployable boomaugments these advantages by increasing the actuation moment torque which in turn increases the achievable s/c roll, pitch or yaw rates while conserving propellant and power.In Phase I, Busek will focus on the MPACS development. In Phase II the MPACS and a boom fabricated by CTD will be integrated and demonstrated. The proposed development will benefit, and at times enable, various government and commercial missions, particularly those that require rapid reorientation of the s/c, and very precise pointing such as high resolution imaging and control of large spacestructures. Development of the boom structure that contains power and signal wiring will benefit the general field of multifunctional composites. Development of novel techniques for multifunctional EMC structure fabrication will pioneer the field.