Joel Shields

Jet Propulsion Laboratory, California Institute of Technology

Papers

Total Citations

H-Index

About

Joel Shields is a specialist in spacecraft dynamics, estimation, and formation flying, with a career focused on bridging theoretical control methods with practical, flight-like validation. His most significant contribution is a novel formulation for spacecraft inertia estimation, presented in his highly cited 2006 paper "Spacecraft Inertia Estimation Via Constrained Least Squares" (34 citations). This work reframes the estimation problem using constrained least squares with linear matrix inequalities (LMIs), providing explicit bounds on the inertia matrix—a critical improvement for ensuring robust attitude control from noisy flight data. Beyond estimation theory, Shields has made key contributions to the experimental validation of precision formation maneuvers. His 2008 paper on "Flight-Like Ground Demonstrations of Precision Maneuvers for Spacecraft Formations" (6 citations) details synchronized formation rotations, a core requirement for future interferometric science missions. He also played a central role in developing the Formation Control Testbed (FCT), including its celestial sensor, as documented in his 2005 work (4 citations). This ground-based, multi-robot testbed, using linear and spherical air bearings to emulate drag-free space, remains a notable achievement for its ability to simulate 6-DOF spacecraft interactions in a representative environment.