(Georgia Institute of Technology, 2024-01)
Gabhart, Austin; Drosendahl, Madilyn; Robertson, Bradford E.; Steffens, Michael J.; Mavris, Dimitri N.
Cislunar operations are expected to rise dramatically within the next decade, requiring a
comparable increase in PNT and communications services. However, current PNT systems
are at capacity and need to be augmented to serve a cislunar space domain, specifically in the
form of novel cislunar PNT architectures. This paper studies the problem of the deployment of
PNT and communications satellites, specifically, the problem of deployment strategies spanning
multiple stages over extended periods of time. A set of stage definitions will be determined along
with areas of potential user activity. A novel application of the hidden gene genetic algorithm to
the constellation optimization problem is presented. A design space exploration is presented
with comparisons of circular and elliptical constellations. Optimization results from the first
stage are also provided. It is shown that acceptable performance can be achieved with a low
number of deployed satellites and that strong trade-offs exist between performance and stability.
(Georgia Institute of Technology, 2023-01)
Bender, Theresa; Gabhart, Austin; Steffens, Michael; Mavris, Dimitri N.
Operations in cislunar space are expected to greatly increase over the next decade, which will place a heightened demand on position, navigation, and timing (PNT) architectures. Existing PNT systems will be unable to support this growth, evidencing the need for a new cislunar PNT infrastructure. This study defines and parameterizes the design space for cislunar PNT architecture development, with the goal of enabling design space exploration and architecture trade studies. Design choices such as orbit type, architecture symmetry, and preferred design variables and their ranges are discussed. An environment for modeling and evaluating PNT architectures is developed and demonstrated on a subset of the defined design space. Preliminary results are shown to exhibit the type of data and trends to be expected from these studies. A discussion of optimization algorithms that can leverage this environment to fully explore the defined design space and identify optimal designs is presented.
(Georgia Institute of Technology, 2022-06)
Patel, Rohan; Hadley, Jack; Gabhart, Austin; Singla, Deepika; Wei, Xiao (Olin); Grant, Jacob; Robertson, Nicole; Weston, Neil; Steffens, Michael; Mavris, Dimitri N.
As naval architects consider the construction of long-term autonomous maritime systems, the naval design process will be modified. The incorporation of reliability analysis in conceptual design is needed to enable systems incapable of in-theater maintenance. The use of reliability analysis is demonstrated with notional architecture, redundancy, and component requirement trades.