meetings - Space Flight Mechanics Committee

9:00 AAS Using TableSat IC for the Analysis of Attitude Control and Flexible Boom
13-291 Dynamics for NASA Magnetospheric MultiScale (MMS) Mission Spacecraft
Joshua Chabot, University of New Hampshire; Joseph Kelley, University of New
Hampshire; Michael Johnson, University of New Hampshire; May-Win Thein,
University of New Hampshire
The NASA Magnetospheric MultiScale (MMS) Mission consists of four spin-stabilized
spacecraft (s/c) flying in precise formation. The UNH MMS TableSat IC, a limited 3-DOF
rotation (full spin, limited nutation) table top prototype of the MMS s/c, is constructed to
analyze the MMS s/c dynamics. A quaternion-based PID controller is implemented on
TableSat IC to observe the effects of spin rate and nutation control on the experimental s/c
bus as well as the scaled booms. The experimental results of the s/c bus are expected to
match those of predicted analytical results.
9:20 AAS Three-axis Attitude Control using Redundant Reaction Wheels with
13-292 Continuous Momentum Dumping
Erik Hogan, University of Colorado at Boulder; Hanspeter Schaub, University of
Colorado
9:40 Break
In this paper, a description of an attitude control system for a 3-axis stabilized spacecraft is
presented. Using modified Rodgrigues parameters, a globally stabilizing nonlinear feedback
control law that incorporates integral feedback is derived that enables tracking of an
arbitrary, time-varying reference attitude. This new control avoids any quadratic rate
feedback components. A cluster of four reaction wheels (RWs) is used to control the
spacecraft, and three magnetic torque rods are used for purposes of continuous autonomous
momentum dumping. The momentum dumping strategy can employ general torque rod
orientations, and is developed for the case of 4 RWs.
10:05 AAS Internal Moving Mass Spherical Pendulum Concept for Re-entry Vehicle
13-293 Attitude and Trajectory Control
Brad Atkins, Virginia Polytechnic Institute and State University; Troy Henderson,
Virginia Polytechnic Institute and State University
We present a general formulation with respect to the instantaneous center of mass for a reentry
vehicle with n internal masses for attitude control. The masses are permitted to have
inertia and both translate and rotate with respect to the base vehicle coordinate frame. An 8
DOF nonlinear simulation of a spherical pendulum configuration is provided using the
formulation for a preliminary demonstration of the system to control the attitude and shape
the vehicle trajectory of a re-entry vehicle. The full paper will include a LQR based
autopilot algorithm for attitude stabilization and trajectory tracking.
23 rd AAS / AIAA Space Flight Mechanics Meeting Page 45