(Georgia Institute of Technology, 2024-01)
Dean, Hayden V.; Decker, Kenneth; Robertson, Bradford E.; Mavris, Dimitri N.
Blunt-body entry vehicles display complex flow phenomena that results in dynamic instabilities in the low supersonic to transonic flight regime. Dynamic stability coefficients are typically calculated through parameter identification and trajectory regression techniques using both physical test data and Computational Fluid Dynamics (CFD) simulations. This methodology can generate dynamic stability coefficients, but the resulting data points are limited, and have high degrees of uncertainty due to the nature of data reduction methods. With increased computational capabilities, new methods for dynamic stability quantification have been explored that seek to leverage the high-dimensional aerodynamic data produced from CFD simulations to compute dynamic stability behavior and address the limitations of linearized aerodynamics. The objective of this work is to advance the quantification of dynamic stability behavior of blunt-body entry vehicles by leveraging high-fidelity CFD data through Reduced Order Modeling (ROM). ROMs are capable of leveraging high-fidelity aerodynamic data in a cost effective manner by finding a low-dimensional representation of the Full Order Model (FOM). ROMs based on Proper Orthogonal Decomposition (POD) have shown success in recreating CFD analyses of parametric ROM applications and time-varying ROM applications. Results of this research demonstrated success in constructing two ROMs of a notional blunt-body entry vehicle to recreate heatshield and backshell pressure distributions from forced oscillation trajectories. The ROM was more successful at reconstructing the heatshield pressure distribution, with challenges arising in predicting the chaotic response of backshell latent coordinates.
(Georgia Institute of Technology, 2023-01)
Dean, Hayden V.; Robertson, Bradford E.; Mavris, Dimitri N.
Human missions to Mars will require advanced entry, descent, and landing (EDL) technology
to safely land payloads onto the planet’s surface. With rapidly increasing mass requirements, and
stagnant geometry constraints set by current launch vehicles, non-heritage EDL vehicles must be
considered to safely land human-scale payloads on Mars. The hypersonic inflatable aerodynamic
decelerator (HIAD) is an EDL architecture being evaluated for human-scale payloads to Mars.
Parameterization of a HIAD using important geometry variables is generated and used to
explore the feasible design space of the entry architecture. The design space is evaluated
using GT-Hypersonics, a multidisciplinary design analysis and optimization environment that
combines ESP, CBAero, a Dymos-based trajectory optimizer, TPSSizer, and FIAT to perform
trajectory, aerodynamic, and aerothermodynamic analysis on a given entry vehicle geometry,
and prescribed flight parameters. This analysis is used to size the vehicle’s TPS system, and
determine loads experienced by the vehicle during entry. Ranges for geometric inputs were
selected and implemented to explore the design space of the HIAD architecture for a use case on
Mars using uncrewed and crewed mission constraints. The design spaces for both the uncrewed
and crewed missions demonstrated flexibility of inputs, allowing for multiple configurations to
be used successfully in a mission to Mars. This study was useful in understanding the future
of using the HIAD architecture in space exploration. This study demonstrates the ability to
rapidly generate vehicle designs and evaluate their feasibility, a capability that will be useful in
the growing space industry.