Aerospace Engineering Commons^™

Atmospheric Waves Experiment (Awe) Thermal Control System: Review Of On-Orbit Performance, Matthew I. Ralphs, Mike Holt

Space Dynamics Laboratory Publications

This paper reviews the Atmospheric Waves Experiment (AWE) detector thermal control system’s (TCS) performance for over two years of operation on the Internation Space Station (ISS). The TCS employs active thermal control for the InGaAs detectors with thermoelectric coolers (TEC). Each of the four detectors are controlled by a dedicated TEC at a nominal setpoint of -30°C, with heat transported away via low-mass, high-conductance pyrolytic graphite sheet (PGS) thermal straps into a nickel-plated copper conductor bar. A bi-directional radiator with Silver Teflon ensures an unobstructed view that can radiate the heat away to space. Titanium isolators decouple the detectors from …

A Suite Of Thermal Switches For Surviving Extreme Thermal Environments In Space, Matthew I. Ralphs, Matt Jensen, Alexis Eames, Matt Sinfield

Space Dynamics Laboratory Publications

Thermal switches are a key enabling technology for spacecraft operating in extreme thermal environments. Whether surviving the lunar night, managing intermittent high-power loads from deep space communication systems, or dealing with other extreme thermal environments, high-performance thermal switches allow critical missions to operate beyond conventional thermal design limits. This paper presents the development, testing, and performance of a suite of passive thermal switches designed for both spacecraft- and subsystem-level thermal control. The suite includes: (1) traditional in-line switch placed between sensitive components and radiators; (2) compact designs suitable for integration into standard bolted joint interfaces to modulate the conductance between …

An Investigation Of A Mach 15 Flow Over A Blunt Wedge Using First-Principles Potential Energy Surfaces: Influence Of Wall Temperature, Paolo Valentini, Zach Davis, Maninder S. Grover, Nicholas J. Bisek

Space Dynamics Laboratory Publications

The simulation of a Mach 15 air flow over a blunt wedge is conducted using the direct molecular simulation (DMS) method. Due to partial dissociation of the air mixture at the imposed free stream conditions, the shock layer contains N₂, O₂, NO, N, and O. All potential energy surfaces (PESs) used to model the various molecular interactions only describe electronic ground states energetics. Thus, no electronic excitation is modeled. An isothermal wall boundary condition is imposed, with full momentum and energy accommodation. Two wall temperatures are considered in this work, namely 1,000 K and 2,000 K. …

Hypersonic Non-Equilibrium Cfd And Dsmc Model Comparisons With The Varda Reentry Capsule, Jack D. Crespo, Paolo Valentini, Ashwin P. Rao, Zach S. Davis

Space Dynamics Laboratory Publications

Nonequilibrium aerothermodynamic modeling of the Varda hypersonic testbed capsule is conducted with direct simulation Monte Carlo (DSMC) and computational fluid dynamics (CFD) solvers. Flowfield properties at the 78 km reentry trajectory point are extracted to compute line of sight spectral radiance using two radiative emission codes, namely HARA and NEQAIR. Computed spectra are compared to spectral radiance measured by an in situ optical emission spectroscopy payload flown on Varda’s W-2 capsule in 2025. Model comparisons to the experimental data reveal discrepancies between the HARA and NEQAIR radiative emission predictions in both overall magnitude and qualitative behavior. NEQAIR was found to …

Simulation Results Of Spaceborne Ssa Using A Comprehensive Passive Radar Model, Chinmay Gaikwad, Filipe Senra, Thomas Alan Lovell, Hao Peng, Berker Pekoz, Tianyu Yang

Publications

In this paper, a high-fidelity simulation framework is developed to assess the feasibility of tracking space debris using a large low-Earth orbit (LEO) satellite constellation equipped with onboard passive radar sensors. By exploiting illumination from a distributed network of ground-based transmitters, the constellation provides consistent line-of-sight access to debris objects at higher altitudes, enabling angles-only detection and tracking. This approach yields a scalable, automated, and cost-effective architecture for next-generation space surveillance and contributes to more resilient space traffic management. A complete angles-only passive-radar orbit-determination pipeline is introduced and demonstrated. Initial orbital states are generated using a rate-aware constrained admissible-region multiple-hypothesis …

Large-Scale Cubesat Chassis, Matthew D. Evans, Robert A. Bettinger

AFIT Patents

The present invention relates to large-scale CubeSat chassis and methods of making and using same. The disclosed CubeSat comprises specific structural features that can yield up to at least a 27 U CubeSat that has comparable or even better performance and benefits than that of smaller CubeSats. Such volume increase coupled with the structural integrity of Applicants' CubeSats opens up a wide range of CubeSat performance increases including, but not limited to, larger payloads, more diverse payloads and larger CubeSat fuel capacities. Such increased payload capabilities includes, for example, increased focal length capabilities and such improved maneuverability results in, for …

Model-Based Investigation Of The Influence Of Environmental Conditions On The Energy Supply Of Multirotor Uavs, Morten Roßberg, Hanna Dibbern, Claudia Werner

Journal of Aviation Technology and Engineering

Flight time of unmanned aerial vehicles (UAVs) is limited by available energy, which is affected by the mission profile and external factors, such as environmental conditions. Two main environmental conditions that need to be considered are the impact of wind and ambient temperature on the UAV and its energy supply. The purpose of this study is to examine the effects of wind and ambient temperature to conduct a preliminary evaluation of flight performance and flight limitations. For this reason, three locations in the United States—New York City, Miami, and Fairbanks—are selected and the impact of the considered environmental conditions of …

Dynamic Thrust Testbed For Uav Electric Motors, Colin M. Flowers, Robert C. Johnson Jr., Carson P. Holt

Williams Honors College, Honors Research Projects

This project seeks to bring new testing capability to the Zips Aero Design Team through the design, manufacture, integration, and testing of a dynamic thrust testbed for UAV electric motors. The project centers upon the revival and modification of a past prototype aircraft for use as a testbed for in-flight thrust measuring and recording. The team currently lacks the ability to test dynamic thrust under the operating conditions and flight speeds that are encountered in competition. Project technical areas include component and product design, electrical and electronics, and fluid mechanics, including the use of SolidWorks, MATLAB, and ArduPilot. Aside from …

Set-Theoretic Reachability-Informed Model Predictive Control For Mechanical And Aerospace Systems, Jinaykumar Nitinkumar Patel

Mechanical and Aerospace Engineering Dissertations

Modern mechanical and aerospace systems increasingly operate autonomously in environments characterized by nonlinear dynamics, uncertainty, and safety constraints. In these settings, estimation and control methods based on nominal models and single-point trajectory predictions are usually insufficient to ensure safe and reliable operation. This dissertation uses a set-theoretic perspective, in which the system state, uncertainty, and admissible behavior are described by sets instead of point estimates. The key question is not only what the state is, but what set of states remains consistent with the dynamics, disturbances, control limits, and available measurements. This provides bounded descriptions of uncertainty and supports control …

Numerical Investigation Of Injector Location And Equivalence Ratio In A Flame‐Holder Cavity Scramjet, Matthew Sorenson

Electronic Theses and Dissertations

This thesis presents a CFD-based parametric study of injector location and fuel rate in an ethylene-fueled flame-holder cavity scramjet using STAR-CCM+. Simulations are performed for three injector locations (x/D = 18, 36, and 54) and nine equivalence ratios spanning from ϕ = 0.2 to 1.0 in 0.1 increments. The study aims to determine how injector placement and fueling level alter scramjet performance across a broad operating sweep. The results show a clear regime change between ϕ = 0.2 and ϕ ≥ 0.3. At ϕ = 0.2, combustor behavior is weakly sensitive to injector location compared to the higher-fueling cases. For …

Assessment Of Simulation Software Used For Cubesat Gnc Verification And Validation By University Research Teams, Alexander Taiyo Newett

Masters Theses

As the growth in university satellite teams continues, along with the greater trend in the small satellite market, the need for a guidance, navigation, and control verification and validation pipeline suitable for these young and inexperienced teams becomes evident. Much of the mathematical theory and software implementation of GNC concepts are large hurdles for teams largely composed of undergraduate students.

Many software packages exist that can help these teams achieve GNC verification and validation. If the learning curves of these software packages can be overcome, new satellite teams have the opportunity to better build and test GNC algorithms that are …

Autonomous Navigation Development And On-Ground Validation For Satellite Rendezvous And Proximity Operations, Logan Banker

Masters Theses

Spacecraft rendezvous and docking are critical mission phases for various applications of spaceflight, including active debris removal (ADR) and in-orbit servicing, assembly, and manufacturing (ISAM). While previous missions utilized humans to perform rendezvous and docking, this style of mission greatly increases safety risks and cannot be implemented on a large scale. Autonomous servicing satellites provide a path towards scalable rendezvous and proximity operations (RPO) because these autonomous agents do not require human intervention. This work presents a lightweight convolutional neural network (CNN) for the navigation system of an agent which analyzes monocular images and predicts the target's position and orientation …

Assessment And Comparison Of Selected Carbon Ablation Models In Hypersonic Free-Flight And Arc-Jet Conditions, Andrew Steven Heider

Masters Theses

Accurate prediction of ablative thermal protection system (TPS) performance is critical for hypersonic vehicle design. However, numerical prediction of ablation remains challenging because results are influenced by complex physics and the choice of surface chemistry model and assumptions made in material response calculations. The objective of this work is to evaluate several carbon ablation models and their implementation within modern computational fluid dynamics (CFD) codes. Numerical simulations were performed using NASA’s LAURA flow solver and the commercial CFD code ANSYS Fluent, which coupled Navier-Stokes with surface chemistry models describing carbon oxidation, nitridation, and sublimation reactions. Several reaction sets were considered, …

Embeddable Optical Fiber Sensor For Simultaneous Strain And Temperature Monitoring, Amardeep Kaur, Sudharshan Anandan, Steve Eugene Watkins, Yinan Zhang, Kumbla Chandrashekhara, Hai Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

We present an embeddable hybrid optical fiber sensor based on a cascaded extrinsic Fabry–Pérot interferometer (EFPI) and intrinsic Fabry–Pérot interferometer (IFPI) for simultaneous strain and temperature monitoring in high-performance composite materials. The sensor is fabricated using femtosecond laser micromachining and is embedded within bismaleimide composite laminates manufactured via an out-of-autoclave process. Experimental results demonstrate linear and decoupled responses to strain and temperature, with the EFPI showing minimal temperature sensitivity (1.7 pm/°C) and the IFPI exhibiting high temperature sensitivity (16.1 pm/°C). Strain sensitivities for both components were consistent at 0.6pm/με in embedded conditions. The sensor maintained structural integrity and stable spectral …

A Large Thermal Vacuum (Tvac) Facility To Simulate Cryogenic Space Environments, Emmanuel Kofi Asuako Wie-Addo, Lucas Alexander Scott, Frank Daoru Han

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This work reports the upgrade of a 10-ft (3.0 m) long x 6-ft (1.8 m) diameter vacuum facility as part of ongoing efforts to address some of the technology gaps in NASA's Moon to Mars mission architecture, which include systems to survive and operate through extended periods in extreme environments. Consequently, a removable thermal shroud has been fabricated and installed to facilitate the simulation of extreme cryogenic conditions. The cooling rates of the shroud and a surrogate test article, using liquid nitrogen as the coolant are analyzed and documented under varying vacuum environments during cryogenic testing. The attainable vacuum level …

A Combined Tomographic Particle Image Velocimetry And Numerical Simulation Approach For Supersonic Wind Tunnel Calibration, Joshua Gary, Josiah Mcdermott, Kyle Worden, Serhat Hosder, Davide Viganò

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Supersonic wind tunnels remain essential tools for high-speed aerodynamics research, yet the characterization of their free-stream conditions remains technically challenging and lacks standardized criteria for defining "good" flow quality. While traditional calibration methods rely on intrusive probes, recent advances in optical diagnostics offer new opportunities for non-intrusive characterization. In this work, we demonstrate a novel use of Tomographic Particle Image Velocimetry (Tomo-PIV), combined with numerical simulations, as a methodology for supersonic wind tunnel calibration. The approach is applied to the recently upgraded Missouri S&T Supersonic Wind Tunnel, where Tomo-PIV measurements reveal uniform flow with low angularity and low turbulent noise …

Physics-Constrained Generative Adversarial Networks For Dimensionality Reduction In Optimization, Samuel Sisk, Xiaosong Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Electric vertical takeoff and landing (eVTOL) aircraft make a unique form of urban air mobility due to their low noise, zero emission, and precision control. To maximize efficiency, high-fidelity simulation-based multidisciplinary design optimization discovers the optimal balance among subsystems within an eVTOL. However, conventional multidisciplinary design optimization is computationally intensive due to excessive high-fidelity model evaluations. Moreover, complex nonlinear constraints deteriorate optimization efficiency and convergence. While surrogate models enable efficient design optimization, surrogate modeling suffers in large-scale applications and surrogate-based optimization still has to deal with nonlinear constraints. To address these challenges, the authors' previous work proposed physics-constrained generative adversarial …

Optimal Takeoff Trajectory Prediction Of Electric Drones Based On A Fully Automated Optimal Experimental Design Method, Jiachen Wang, Dheeraj Paramkusham, Xiaosong Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Electric vertical takeoff and landing (eVTOL) aircraft is attracting great interest as a viable solution to promote urban aerial mobility with promising flexibility as well as emission reductions. However, the low specific energy of the current battery is still a strong constraint on the range and endurance of eVTOL flights, especially considering the significant power demands during the takeoff process. Engineering design optimization permits promising solutions for the minimum takeoff energy consumption but can be computationally intensive due to iteratively evaluating simulation models. Surrogate-based design optimization is efficient but still relies on optimization iterations which prohibit real-time decision-making. To fill …

Tomo-Piv Study Of Baseline Flow Structures Behind A Strut Injector, Josiah Mcdermott, Connor Bell, Davide Viganò

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Stabilizing combustion in scramjet engines is a formidable challenge due to the small-time scales afforded for air-fuel mixing. Numerous studies in this area have demonstrated the potential of strut-style platforms for fuel injection and mixing enhancement, which remains an active area of research. In the Aerodynamics Research Laboratory at Missouri S&T, a strut-style injector system has recently been installed. In this study, we characterize the baseline flow structures behind this platform absent fuel injection. The wake generated by a strut itself has an appreciable impact on the resulting air-fuel mixing, which motivates its characterization. In future studies, this characterization will …

Anisotropic Second-Harmonic Ince-Gaussian Beam Generation Using Nbobr2 Holograms, Jayanta Deka, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Ince-Gaussian (IG) modes are a complete and orthogonal set of solutions to the paraxial wave equation in elliptic coordinates representing a continuous transition between Hermite-Gaussian modes and Laguerre-Gaussian modes. Chip-scale platforms to generate IG beams have great significance for various applications, including optical trapping and micromanipulation of particles, optical communication, and quantum optics. On the other hand, materials with high optical anisotropy are crucial for building polarization-sensitive optical devices. In this context, niobium oxide dihalides are a new class of ferroelectric materials exhibiting strong, tailorable, and highly anisotropic second-harmonic generation responses. Here, we report the generation of highly anisotropic second-harmonic …