2026-09-20T15:48:59Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/120145 2023-09-04 col_2142_5131 col_2142_14800 com_2142_5130 com_2142_14799 com_2142_234

Woollands, Robyn 2023-05 application/pdf en text Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-09-01 without embargo terms The student, Himmat Panag, accepted the attached license on 2023-04-28 at 15:53. The student, Himmat Panag, submitted this Thesis for approval on 2023-04-28 at 16:27. This Thesis was approved for publication on 2023-05-02 at 16:49. DSpace SAF Submission Ingestion Package generated from Vireo submission #19256 on 2023-09-01 at 16:56:00 Reducing spacecraft thruster plume contamination using convex optimization Panag, Himmat Singh 2023-05-02 Convex Optimization Plume Contamination Thruster Pointing Constraints Successive Approximations Commercialization of space has opened the door to a multitude of possibilities for on-orbit servicing, assembly and manufacturing missions. Rendezvous, proximity operations and docking are key elements of such missions, and extreme care must be taken to avoid thruster plume contamination of delicate sensors or payloads onboard either vehicle. In this paper we present a thorough investigation into the key sources of contamination for chemical and electric thrusters operating in close proximity to another vehicle. We develop first order plume models, to approximate thruster induced contamination, for use in our trajectory planning simulations. Fuel-optimal approach trajectories from the chaser/servicer satellite to the target/client satellite are computed using convex optimization, where the Clohessy-Wilteshire equations are used to represent the system dynamics. We then re-solve the problem while restricting the thruster pointing region by formulating a non-convex pointing constraint. This constraint is incorporated using a successive approximations method and leads to converged trajectories that reduce contamination of designated areas on the target vehicle, while keeping the required ∆V for the maneuver relatively low compared with the unconstrained problem. As expected, results confirm that incorporating this pointing constraint into the convex optimization problem leads to trajectories that are significantly more fuel efficient than those where an arbitrary non-optimal pointing constraint is simply enforced at specific times to avoid contamination. Text eng https://hdl.handle.net/2142/120145 Copyright 2023 Himmat Panag M.S. Thesis Aerospace Engineering University of Illinois at Urbana-Champaign Aerospace Engineering