Aerospace Engineering Commons^™

Mitigating Out-Of-Plane Fiber Waviness In Afp Laminates With Tow-Gaps Via Selective Placement Of Thermoplastic Veils, Ahmadreza Ravangard, Kuthan Celebi, Sergii G. Kravchenko, Oleksandr G. Kravchenko

Mechanical & Aerospace Engineering Faculty Publications

Fiber tow-gaps and overlaps formed during the Automated Fiber Placement (AFP) process pose a significant challenge by introducing non-uniform composite morphologies, often characterized by resin-rich regions and fiber waviness. These defects occur as deposited fibers sink into the gap regions during consolidation, with gap geometry determined during path planning. Such morphological inconsistencies can compromise structural reliability by initiating premature failure, particularly through localized out-of-plane waviness and resin accumulation. This study investigates the integration of high melting temperature thermoplastic veils, specifically polyetherimide (PEI), into fiber tow-gaps as a method to prevent ply sinking and reduce fiber waviness on both internal and …

Extending The Applicability Of Thermal Protection System Ballistic Limit Equations Beyond The Testable Regime, William P. Schonberg, Michael D. Squire

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Spacecraft use thermal insulation in their design, which is usually placed on their exterior. As such, it is susceptible to high-speed impacts by meteoroids and orbital debris, which can damage it to a point where the protection it offers is below acceptable limits. It is important to be able to characterize expected levels of damage stemming from such high-speed impacts. In this paper, we extend the applicability of a previously developed ballistic limit equation (BLE) for one such thermal insulation material using the results of a series of Smooth Particle Hydrodynamics Code (SPHC) impact simulations at velocities in excess of …

Anisotropic And Temperature-Tunable Second-Harmonic Vortex Generation In Ferroelectric Nbocl2 Holograms, Jayanta Deka, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Optical vortex beams with helical phase fronts have immense potential to enhance data capacity due to the unbounded values of orbital angular momentum. Chip-scale platforms for producing vortex beams are of paramount importance for a variety of applications. On the other hand, 2D materials with unique optical properties are essential for developing multifunctional ultrathin photonic devices. Here, anisotropic and temperature-tunable second-harmonic vortex beam generation is demonstrated with ultrathin ferroelectric niobium oxide dichloride (NbOCl₂) fork holograms. The polarization-resolved Raman measurements are performed on the NbOCl₂ crystal to understand the anisotropic behavior of the Raman modes. It is demonstrated …

Hydrogen Standards And Aviation Sustainability, Eva Maleviti, Evan Stamoulis, Elen Paraschi

Publications

Standards from ISO, SAE, and ASTM are essential for certification, safety, and sustainability validation.

Hydrogen Readiness In Aviation & Challenges- Technology Meets Regulation And Market Demand, Eva Maleviti

Publications

Where technology meets regulation and market demand.

Program And Proceedings: Nebraska Academy Of Sciences 1880–2025, 145th Anniversary Year, One Hundred-Thirty-Fifth Annual Meeting

Nebraska Academy of Sciences: Programs and Proceedings

Program

Aeronautics and Space Science

Biological and Medical Sciences

Biology

Chemistry

Earth Sciences

Science Education

Anthropology

Applied Science and Technology

Physics and Engineering

Forensic Sciences

Ecology, Sustainability, and Environmental Science

Maiben Lecture: Mary Ann Vinton, "State of the Academy"

Friends of Science Awards: David Crouse and Daniel Sitzman

Navigating Together: The Conav Testbed And Framework For Benchmarking Cooperative Localization, Rohith Boyinine, Jayanth Ammapalli, Anusna Chakraborty, Rajnikant Sharma, Kevin Brink, Clark N. Taylor

Faculty Publications

This paper presents CoNaV, a comprehensive framework for creating a multi-vehicle cooperative localization (CL) testbed designed to support the benchmarking, development, and deployment of cooperative navigation algorithms. Given the essential role of CL in improving localization accuracy for both defense and civilian applications, CoNaV provides a robust environment for rigorously validating algorithms under real-world conditions. By establishing a benchmark for CL algorithms, CoNaV lays a foundation for advancing research into more sophisticated and distributed CL solutions. This framework highlights the potential of cooperative navigation to enhance multi-vehicle operations and offers a scalable, practical approach for future developments in CL technology.

The Space Rescue Professional: Operationalizing Guardians For The Future, Benjamin Johnis, Robert Bettinger, James Dean

Faculty Publications

The escalating competition in space exploration demands a dedicated space rescue capability. This article argues for the establishment of a space rescue professional (SRP) career field within the Department of Defense and the US Space Force. By harnessing existing US Air Force combat rescue expertise and partnering with the National Aeronautics and Space Administration, the Space Force can rapidly develop a robust SRP program with the warrant officer corps as its backbone. This article addresses a critical gap in national space policy to outline a cost-effective dual-service training pipeline and SRP operational roles. Such an investment safeguards astronauts, bolsters US …

Computation Of Natural Relative Trajectories In The Elliptic Restricted Three-Body Problem, Dane Huck

Masters Theses

"Humankind’s presence in deep space is certain to increase throughout future decades. Future missions will continue to exploit the complex dynamics making use of liberation point orbits. Along with this trend is the rise of small satellites ("small sats") and fractionated spacecraft in general. Compared to traditional monolithic spacecraft, small sats can often have higher maneuverability, be a fraction of the cost, and be more expendable in nature. The growing interest in these two areas drives the need for improvements in the area of relative motion in deep space. One obvious use of small sats in deep space is for …

Ground Testing Of Cryogenic Environments In Vacuum Conditions, Lucas A. Scott

Masters Theses

The environment in the vacuum of space is unforgiving and ever-changing. Not only facing the lack of a protective atmosphere, but powerful radiation and extreme temperature ranges as well. Equipment destined for space must be hardened to withstand them. Just launching satellites that are theoretically able to survive these conditions is unfeasibly costly in the event of failure. Because of this, spacecraft must be tested in a simulated environment that can match the harsh climate in space. Therefore, it is the goal of the Gas and Plasma Dynamics Lab's (GPDL) to test and prove specific methods of recreating these conditions. …

Generative Adversarial Networks For Dimensionality Reduction In Evtol Aircraft Takeoff Trajectory Optimization, Samuel Sisk, Farzaam Khorasani-Gerdehkouhi, Abdulaziz Abutunis, K. Chandrashekhara, Xiaosong Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Electric vertical takeoff and landing (eVTOL) aircraft play a key role in urban air mobility (UAM), which aims to alleviate traffic congestion in urban areas. Despite their value, eVTOL aircraft suffer from battery energy consumption, which affects their range and endurance in real world flight tasks. Especially, the takeoff process has been identified for excessive power demands. Multidisciplinary analysis and optimization manage to discover optimal takeoff trajectories with minimum energy consumption while balancing multidisciplinary trade-offs, such as short distance takeoff and passengers' comfort. However, conventional parametrization methods (such as B-spline curves) leverage an empirically high-dimensional design space to include real …

Multifidelity Dust Erosion Analysis Of Mars Entry Vehicles, Adam Boland, Dominic Zanti, Serhat Hosder, Andrew Hinkle

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The objective of this paper is to present a multifidelity approach for estimating recession rate and kinetic energy impact rate on the surface of planetary entry vehicles operating in dusty atmospheric environments at hypersonic speeds. The multifidelity model used a co-Kriging approach that combined a low-fidelity correlation with a correction factor from high-fidelity CFD solutions. The developed multifidelity model enables efficient and accurate exploration of a design space to determine at what conditions encountering dust is most dangerous to TPS survivability. Two sample problems are used to demonstrate the effectiveness of the approach: the Mars 2020 lander and a HIAD-type …

Improving Neural Network Efficiency With Multi-Fidelity And Dimensionality Reduction Techniques, Vignesh Sella, Thomas O'Leary-Roseberry, Xiaosong Du, Mengwu Guo, Joaquim R.R.A. Martins, Omar Ghattas, Karen Willcox, Anirban Chaudhuri

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Design problems in aerospace engineering often require numerous evaluations of expensive to-evaluate high-fidelity models, resulting in prohibitive computational costs. One way to address the computational cost is through building surrogates, such as deep neural networks (DNNs). However, DNNs may only be an effective surrogate when sufficient evaluations of the high-fidelity model are required such that the up-front training cost is amortized, or in situations that require real-time responses (such as interactive visualizations). Typically, the data requirements for adequately accurate training of DNNs are often impractical for engineering applications. To alleviate this issue, the proposed work utilizes output dimensionality reduction along …

Characterizing Intralaminar Distal Crack And Delamination In Multidirectional Laminates Under Low Velocity Impact: Modeling Approach With Ultrasound Testing Validation, Niildiip Chandraa, Rachel Van Lear, Arief Yudhanto, Yuqing Zhao, David A. Jack, Douglas E. Smith

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multidirectional laminated composites are essential for load-bearing structures, especially under frequent impact loading. While existing modeling techniques simulate various impact damage modes, our understanding of the underlying mechanisms, specifically the initiation and progression of intralaminar distal cracks and interlaminar delamination, needs improvement. Validating these mechanisms is crucial for enhancing modeling accuracy and expediting the design process. In this work, we propose a three-dimensional finite element modeling (3D FEM) approach aimed at elucidating the impact damage mechanisms in multidirectional carbon fiber reinforced polymer (CFRP). Our model incorporates cohesive zone models (CZM) to simulate the behavior of intralaminar cracks at distal points …

Phase Change Cells And Verification Of Gallium As Thermal Calibration Reference In Space, Harri Latvakoski, T. Shane Topham, Gail Bingham, Mike Watson, Igor Podolski

Space Dynamics Laboratory Publications

• Phase change cell introduction

• Design and ground testing of on-orbit phase cells

• ISS phase cell flight experiment

Radiometric Sensor Level Calibration For Remote Sensing (Planning, Testing, And Operation), Joe Tansock

Space Dynamics Laboratory Publications

Contents

• What is Calibration and Why is it Important (example) 
• Remote Sensor Calibration Approaches
• Typical Space-based Sensor Lifecycle and Calibration Efforts at SDL
• EO Calibration Applications (example) 
• Example Calibrations at SDL
• Calibration Testing at SDL and example Calibration Equipment
• Calibration is Multi-Path
• Student Employment/Projects to Support SDL Calibration

Calibration For Small Satellite Payloads, Jason Knudsen, Christian Conkle, Alex Allgrunn, Deron Scott

Space Dynamics Laboratory Publications

SDL Presentation on Calibration for Small Satellite Payloads

Rbi Ground Calibration, Harri Latvakoski, Greg Cantwell, James Peterson, Joel Cardon

Space Dynamics Laboratory Publications

• RBI overview

• Ground calibration objectives

• Calibration configurations & chamber setup

• Calibration tests & equipment

Small Satellite Payload Calibration, Deron Scott, Cole Miller, Eli Salay, Shane Canfield, Scott Hansen, Matt Berghout, Jan Kunzler, Duane Miles

Space Dynamics Laboratory Publications

SmallSat missions have cost, time, and scale limitations. Calibration methods can be optimized to enable mission success at a low cost by providing customers the best “bang for their buck.”

Multi-Layered Security Approaches For A Modular Open Network Architecture-Based Satellite, Brandon Shirley, Quinn Young, Peter Wegner, Jacob Christensen, Jeffrey Janicik

Space Dynamics Laboratory Publications

Overview

• Introduction
• Open System Architecture (OSA) and Modular Open Network Architecture (MONA) background
• Security Challenges
• Security Principles
• Solutions