University of Illinois Urbana-Champaign

Linear covariance analysis of atmospheric entry for sample return mission

Zuiker, Nicholas J.

Content Files
ZUIKER-THESIS-2020.pdf

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https://hdl.handle.net/2142/108540

Description

Title
Linear covariance analysis of atmospheric entry for sample return mission
Author(s)
Zuiker, Nicholas J.
Issue Date
2020-07-23
Director of Research (if dissertation) or Advisor (if thesis)
Putnam, Zachary R
Department of Study
Aerospace Engineering
Discipline
Aerospace Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Date of Ingest
2020-10-07T21:00:10Z
Keyword(s)
  • entry
  • covariance
  • atmospheric
Abstract
Linear covariance analysis is an uncertainty analysis tool comparable to Monte Carlo analysis; both provide similar statistical information about the performance and uncertainties of a dynamic system. Linear covariance analysis linearizes the models of a dynamic system and propagates the state uncertainties alongside a reference trajectory. These uncertainties are similar to those computed from post processing a Monte Carlo analysis and require potentially significantly fewer computational resources. A comparison of the two analyses is performed on an example sample return atmospheric entry mission. The example mission is an unguided entry vehicle similar to the Stardust Sample Return Mission. Flight dynamics for entry are modeled with the three-degree-of-freedom translational equations of motion. Uncertainty in vehicle, environmental, and mission design parameters are included to determine expected flight performance. In the analysis, linear covariance results match Monte Carlo within 4% in determining the state uncertainties over the trajectory,while requiring only 0.48% the computational effort relative to Monte Carlo analysis. Further analysis using linear covariance shows that uncertainty in position is the largest contributor to state dispersions. The final state dispersion is highly sensitive to uncertainty in initial position. Comparatively uncertainty in initial velocity contributes much less to the final state dispersion and is insensitive. Varying the initial position dispersion by ±50% results in the largest changes in the 3−σ uncertainty in the altitude at parachute deploy which ranges from 995 m to 2076 m compared to the nominal 1495 m uncertainty.
Graduation Semester
2020-08
Type of Resource
Thesis
Permalink
http://hdl.handle.net/2142/108540
Copyright and License Information
Copyright 2020 Nicholas J Zuiker

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