Ground Testing of Spacecraft Attitude Dynamics During In-Space Assembly and Manufacturing

The on-orbit construction of structures, i.e., in-space assembly and manufacturing (ISAM), is a promising approach for increasing mission flexibility and achieving structures optimized for the space environment. Although many construction processes have been proposed, a critical aspect that needs further investigation is the spacecraft attitude dynamics during ISAM given the large changes in mass properties of the spacecraft and the long timescales of fabrication. This work investigates the ground testing of spacecraft attitude dynamics during Bend-Forming, a candidate process for the on-orbit construction of truss structures via plastic deformation of metallic feedstock. Specifically, we conduct experiments on a planar air bearing platform and develop rigid body dynamics models to understand the platform motion during Bend-Forming. The experimental results reveal 1) the effect of metal springback on the attitude dynamics, and 2) the possibility of control-structure interaction during fabrication with closed-loop, thruster-based position and attitude control. Overall, this study highlights how artifacts of the manufacturing process like springback affect attitude dynamics and results in important guidelines for the ground testing of spacecraft attitude dynamics during ISAM.