Thesis Defense by Curt Holmer on November 30th

Space Studies M.S. candidate, Curt Holmer, will defend his thesis as follows.  All Space Studies students, faculty and staff are encouraged to show your support by attending.

When:  Monday, November 30th at 2:30 pm (Central)

Where:  via Zoom 

Title:  Bio-Regenerative Life Support Systems Functional Stability and Limitations, a Theoretical Modeling Approach

About the Research:  Experiments such as Russia’s BIOS series, NASA’s LMLSTP, ESA’s MELiSSA, and Japan’s CEEF have shown that microalgae and higher plants combined with physical-chemical material converters can be a successful part of a Biological Life Support System or a Closed Ecological Life Support System.  LMLSTP, Melisa, and CEBAS experiments as well as commercial Ecosphere products have proven stability at small-scale with direct dependence, closed-loop systems for both short and extended time periods. This shows that when the dependencies and factors are known and understood creating a small-scale stable environment with known measuring points can be easily accomplished.

However, the larger experiments, such as Biosphere2 or Bios3, have shown that the more complex environment, the more stability issues arise and give way to critical transitions. These transitions are sudden and often irreversible, leading to the collapse of the system. Given the time and scale required to test these dependencies and conditions, knowing the precursors of an impending transition or being able to predict critical transitions in these systems is highly desirable. Generalized models can achieve this and may even reduce the amount of time series data required to validate the stability of a given system.

This research focuses on defining stability for these complex systems as linked through closure degree and tropic network complexity. This link is explored mathematically and then demonstrated by comparing overall observed closure levels of the NASA Johnson Space Center Lunar-Mars Life Support Test Project (LMLSTP) with the proposed closure index and stability level calculations. To demonstrate the applicability of the closure index and stability level calculations, they are examined with longer duration closure simulations.. Additionally, a generalized framework model is constructed to attempt to detect early warning signals of critical transitions and demonstrate the overall stability or instability of the system under observation. These models are tested and demonstrated using computer simulation of theoretical Ecological Closed Life Support Systems (ECLSS) habitats based on the LMLSTP experiments

Advisor:  Dr. Pablo de Leon

About the Presenter: Curt received his M.Sc. in in Information Systems Technology from The George Washington University in 2007. He is currently employed by The Aerospace Corporation supporting satellite ground system programs, providing guidance on software architecture and agile acquisition to ensure program success. Prior to joining The Aerospace Corporation, Mr. Holmer worked for several industry leaders Including IBM, General Dynamics, and Titan Corporation providing architecture and software solutions to Federal Agencies.

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