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oai:www.ideals.illinois.edu:2142/97453 2023-07-11 col_2142_5131 col_2142_14800 com_2142_5130 com_2142_14799 com_2142_234

Putnam, Zachary R. Lorenz, Christopher George 2017-08-10T19:15:59Z 2017-08-10T19:15:59Z 2017-04-25 2017-05 Future large-scale Mars surface exploration missions require landed masses beyond the capability of current entry, descent, and landing technology. High-mass missions will likely use supersonic retropropulsion to increase landed mass, a paradigm shift from current supersonic parachute systems. This work explores hypersonic flight strategies appropriate for use with supersonic retropropulsion systems at Mars. Optimal control techniques are used to determine hypersonic bank-angle profiles that achieve favorable supersonic retroprolusion ignition states. Bang-bang control in the hypersonic flight regime is shown to be optimal for targeting specific state values at terminal descent initation and for minimizing propellant use during propulsive descent. A trade-off between altitude and flight-path angle at supersonic retropropulsion ignition is identified. Minimum-propellant propulsive descent trajectories are identifed and studied parametrically. Results show that hypersonic ballistic coefficient and lift-to-drag ratio have the largest effects on minimum propellant mass fraction; changes to the vehicle state at entry interface have a smaller effect. The space of reachable supersonic retropropulsion ignition states is presented over a range of vehicle and trajectory parameters of interest. Results indicate execution of an appropriate hypersonic flight strategy can significantly reduce the amount of propellant required for supersonic retropulsion systems performing powered descent and landing at Mars. Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-08-10 without embargo terms The student, Christopher Lorenz, accepted the attached license on 2017-04-24 at 12:51. The student, Christopher Lorenz, submitted this Thesis for approval on 2017-04-24 at 12:59. This Thesis was approved for publication on 2017-04-25 at 09:57. DSpace SAF Submission Ingestion Package generated from Vireo submission #11009 on 2017-08-10 at 13:45:39 Made available in DSpace on 2017-08-10T19:15:59Z (GMT). No. of bitstreams: 2 LORENZ-THESIS-2017.pdf: 2162781 bytes, checksum: 26b52abe91cf33c146004389a6490530 (MD5) LICENSE.txt: 4215 bytes, checksum: 02d4c4d849c1c998d9a2e0a373825e90 (MD5) Previous issue date: 2017-04-25 application/pdf http://hdl.handle.net/2142/97453 en Copyright 2017 Christopher G. Lorenz Mars Entry, descent, and landing (EDL) Optimal control Space systems Supersonic retropropulsion Hypersonic Hypersonic flight strategies for supersonic retropropulsion at Mars text text Aerospace Engineering Aerospace Engineering University of Illinois at Urbana-Champaign Thesis M.S.