PhD Proposal by Keir C. Gonyea

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  • Date/Time:
    • Friday December 4, 2015 - Saturday December 5, 2015
      1:00 pm - 2:59 pm
  • Location: Weber 200
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Summary Sentence: Use of the Mars Atmosphere To Improve the Performance of Supersonic Retropropulsion

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Ph.D. Thesis Proposal


Keir C. Gonyea

(Advisor: Prof. Robert D. Braun)



Use of the Mars Atmosphere To Improve the Performance of Supersonic Retropropulsion



Friday December 4 from 9-11am in Weber 200.




NASA has landed seven vehicles on the surface of Mars using parachutes for supersonic descent. Supersonic retropropulsion, thrusting in opposition to the vehicle velocity, is a candidate technology to replace supersonic parachutes but it is hindered by its large propellant mass. Atmospheric-breathing propulsion systems may reduce this mass constraint by ingesting oxidizer from the surrounding atmosphere. However, the Martian atmosphere, which is composed of primarily carbon dioxide, necessitates that metal fuels be used in order to combust the available oxidizer.

This thesis advances the state of the art of atmospheric-breathing supersonic retropropulsion (AB-SRP) by providing a comprehensive analysis methodology for the evaluation of AB-SRP propulsion and vehicle performance as well as designing a reference vehicle for a number of potential mission classes. AB-SRP propulsion performance is assessed via a suite of analysis tools, which are developed to simulate metal - CO2 combustion performance and sensitivity to both the engine design and operating regime. These tools include an equilibrium combustion simulation to evaluate engine efficiency and a finite-rate kinetics simulation to investigate the time-dependent phenomena. Case studies are presented for AB-SRP relevant mixtures and conditions to predict propulsion performance of the AB-SRP engine across a range of conditions and verify that reasonably sized combustion chambers can provide complete combustion of the propellant. The propulsion system results are used in an EDL trajectory simulation, which accounts for the variable engine thrust and efficiency across different flight regimes. Mass capture of the atmospheric oxidizer is also considered. With this simulation, the AB-SRP trade space is explored and favorable AB-SRP vehicle configurations are determined along with an understanding of the performance sensitivities to various parameters. These results inform the baseline AB-SRP vehicle design, encompassing packaging and configuration studies, which are iterated upon to achieve vehicle closure. The baseline vehicle provides a platform from which further, higher-fidelity analysis can be performed.




Dr. Robert D. Braun (advisor)

Dr. Jechiel I. Jagoda

Dr. Brian J. German

Dr. Jerry M. Seitzman

Dr. Aaron H. Auslender


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Graduate Studies

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Phd proposal
  • Created By: Tatianna Richardson
  • Workflow Status: Published
  • Created On: Nov 25, 2015 - 3:07am
  • Last Updated: Oct 7, 2016 - 10:14pm