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Satellite Navigation With Earth Islands for SCOPE-1
No full textSpacecraft optical navigation can deliver autonomous navigation onboard when Earth-based tracking is saturated, obstructed, or impractical. Optical navigation relies on the correspondences between detected and known or mapped features in imagery to extract position and/or velocity, and data-driven methods, which directly leverage collected data to learn, can improve detection performance. This paper presents an initial data-driven Earth-based detection system using islands as landmarks for the SpaceCraft for Optical- based Position Estimation-1 (SCOPE-1) 3U CubeSat, which will be paired on board with a physics-based estimation framework. The system consists of an island detector trained on Earth observation imagery of islands, an identification procedure to match detected islands to a localized catalog, and a measurement model to estimate spacecraft position. The results indicate that navigation using landmarks with this system is feasible in Low Earth Orbit (LEO)
AI-Driven Mission-Critical Software Optimization for Small Satellites: Integrating an Automated Testing Framework
No full textSmall satellites (SmallSats) have revolutionized our modern digital infrastructure, such as Earth observation, navigation, real-time communications, and deep space exploration, due to their composable design, effectively reduced cost, and accelerated development cycles. However, SmallSat software must function autonomously, often under limited bandwidth, processing power, and computing resources. Pre-launch techniques such as Hardware-in-the-Loop (HIL), Software-in-the-Loop (SIL) and Unit testing are generally used, but often insufficient to detect errors, timing anomalies, fault propagation, or further telemetry-based degradations. This paper presents a Python-based validation framework influenced by recent testbeds like EIRSAT-1, ITASAT-2, and NOS3, integrating telemetry simulation, synthetic fault injection, resource logging, anomaly detection, and runtime tuning using machine learning techniques. Synthetic faults, such as memory saturation and packet delays, are injected across 30 test cycles. The structured logs were provided as input to train Random Forest and SVM models. The average latency rate reduces from 1.42s to 0.89s, and the fault rate reduces from 33% to 16.6% with Bayesian tuning. During practice simulations, the results give support to spot faults earlier and enhance performance. As a result, this research provides a helpful automated framework for developers and aerospace engineers to boost the effectiveness of important software used in small satellites
A Dynamic Wireless Channel Emulator for Realistic CubeSat Testing
No full textFailure of the communication subsystem has been responsible for approximately 20% of small satellite mission failures over the period between 2000 and 2019. Insufficient system-level integration and testing has been cited as one reason why corrective actions weren’t taken before launch to prevent such failures. Here, we introduce a relatively inexpensive GTEM-cell-based dynamic channel emulator that will permit designers of CubeSats operating at frequencies up to 20 GHz to evaluate their spacecraft’s communications over multiple simulated passes with the spacecraft in as close to over-the-air flight condition as possible, including fully deployed antennas. Using this over-the-air channel emulator allows the designer to confirm that the communications subsystem will function correctly while experiencing: 1) path loss and Doppler shift, 2) random fading due to satellite motion or rain fading, and/or 3) noise, interference, or scintillation, as applicable, that perfectly matches what would be experienced during actual satellite passes. Our dynamic channel emulator comprises a controller, a pair of channel emulators that operate on the uplink and downlink, respectively, a diplexer, and a GTEM cell into which the satellite is placed. The compact size and relatively low cost of a GTEM cell are significant advantages compared to a full-size anechoic chamber or an open area test site. The ground station transmitter and receiver are disconnected from the ground station antennas and transmitter power amplifier and connected to the uplink and downlink channel emulators. The instantaneous attenuation and Doppler shift on the uplink and downlink are set by a pair of channel emulators of our own design that are driven by standard orbit propagation software (free space path loss and Doppler shift) augmented our own channel models (excess fading due to high frequency signal propagation through hydrometeors and spacecraft tumbling). A fixed attenuator emulates the minimum path loss on the link while a programmable attenuator accounts for excess fading associated with increases in distance, polarization mismatch, or the presence of hydrometeors along the path. An SSB modulator implemented using a software defined radio implements the Doppler shift associated with orbital motion as the satellite approaches and then recedes from the Earth station. A circulator directs signals from the satellite in the GTEM cell into the downlink path, and signals from the uplink path into the satellite in the GTEM cell. It also isolates the uplink and downlink chains from each other. Tests conducted using our dynamic channel emulator can confirm that the communications subsystem will function correctly under ultra-realistic channel conditions, and significantly lower the risk of communications subsystem failure. The basic system can be upgraded to allow simultaneous testing of: 1) the GNSS subsystem by applying simulated GNSS signals that account for the position, speed, and orientation of the CubeSat with respect to the simulated constellation, and 2) the CubeSat’s electrical power system by illuminating the solar cells using a solar simulator. If the standard radio frequency absorber is replaced with closed cell foam, suitable fans and air filters are installed, and appropriate cleaning protocols followed, the GTEM cell can be upgraded to provide an ISO 8 clean room environment and used for flight model testing
Robot Swarm: A Test Platform for Spacecraft Formations
No full textSatellite swarms are transforming space exploration by enabling cost-effective missions and distributed onboard intelligence. Precise formation control is critical for optimized data collection, collaborative sensing, and collision avoidance. NASA’s Starling mission demonstrates how scalable, autonomous swarms enable satellites to operate as a coordinated network in low Earth orbit [1]. This research project offers a practical, cost-effective platform for testing agile swarm formation control using physical robots, enabling testing and validation of formation control algorithms and evaluating their effectiveness. This project tests Interstel’s iCOSMOS-Swarm, a software platform designed for autonomous coordination of unmanned vehicle swarms. The formation includes four robots to represent ChildSats and a static computer to represent the Mothership
Breaking the Boundaries of Aerospace Simulations, HIL and Digital Twins
No full textPoster presented during the 2025 SmallSat Conference
Effect of High Solar Activity on the Orbital Decay Rate of the 3U Cubesat DORA
No full textCubeSats developed at universities seldom have propulsion due to cost and complexity constraints and are very commonly deployed from the ISS into orbits where atmospheric drag is significant. Without propulsion, the time to re-entry is a function of the cross section to mass ratio and the space weather. Many cubesats have limited ways of decreasing ram cross section, e.g. pointing into the wind. Hard radiation from solar activity inflates the atmosphere and increases drag. Since the beginning of the cubesat era, the Sun has been unusually quiescent, at a level not seen for 200 years, which has biased expectations for mission lifetimes. The current solar maximum is higher than the previous and has reduced the lifetime of LEO satellites.
DORA was a joint mission supported by NASA, JPL, ASU’s Low frequency Cosmology and the Interplanetary Lab with help from Amateur radio operators. The satellite was a platform for experiments in the related fields of communications and radio astronomy. The spacecraft was built by students and amateur radio operators local to the Phoenix area and launched in August of 2024, as the solar max was well underway. The spacecraft was released in October and before the end of November 2024, it had re-entered.
This paper investigates the DORA’s trajectory as it descended from the ISS orbit to re-entry in 54 days. We compare the actual trajectory to various analyses including the Space Mission Analysis and Design method, STK simulation and compare with estimates provided by NASA CSLI/KSC DAS. We find that, while these models all perform well, they do rely on forecasts of solar activity. Such a forecast must be made at the mission formulation phase, which for DORA was done when solar maximum was five years in the future. We recommend that future missions deploying below 500 km consider space weather variability as a risk to mission success and include a worst-case level
Empirical Evaluation of Bayes Error Rate Bounds in Binary Classification
No full textClassification tasks are fundamental in statistical machine learning. In classification tasks, a general goal is to build or select a model that can correctly classify data with as few errors as possible. However, for a particular dataset, the minimal number of errors achievable is seldom zero since overlap in the data makes errors unavoidable. As a result, it is often difficult for machine learning practitioners and data scientists to know whether classification errors can be reduced through further refinement. A potential solution to this lies in the Bayes error rate (BER). The BER is the lowest error rate achievable for a given set of features. If known, the BER could give data scientists better ability to gauge the performance of specific models relative to the limitations of the data and thus make more educated decisions on how much time should be spent iterating on existing solutions. In general, the exact class distributions are unknown, so the BER cannot be determined exactly. Instead, research focuses on estimating or bounding the BER as closely as possible given the data. There are a wide variety of ways to try to bound the BER. This thesis discusses several of these methods and aims to characterize how well they can perform in different scenarios where the BER is known. In particular, we seek to quantify how often the true BER actually falls within the lower and upper bounds for the different methods in the literature. This characteristic has been neglected in the prior literature and would help establish the degree to which these bounds can actually be trusted as a reliable tool for classification problems
Why Does Coach Do That? Exploring Influences of Coach Behavior in Non-Elite Women\u27s Artistic Gymnastics
No full textThis two study dissertation explores coaching in women\u27s artistic gymnastics, as the sport has been criticized for harsh and controlling coaching methods. The first study investigated whether coaches who experienced mistreatment as young gymnasts were more likely to adopt controlling coaching practices. While there was no direct link, those with a history of mistreatment tended to struggle more with managing their emotions. The second study tested whether coaches view controlling coaching as more acceptable for younger or more advanced gymnasts. The results showed that neither age nor skill level made a difference—controlling coaching was generally viewed as unacceptable, while supportive coaching was preferred. These findings challenge the long-standing belief that harsh coaching is deeply ingrained in gymnastics. While many current coaches have personal experiences of mistreatment, the sport appears to be shifting toward a more supportive, athlete-centered culture—at least at the non-elite levels. This suggests a growing recognition that gymnasts can thrive with healthier coaching practices
Evaluating the Impact of Maximum Aero-Thermal Heating on a High-Speed Fixed-Wing Atmospheric Aircraft Optimum Trajectory
Get PDFThis study explores how extreme heating affects the flight paths of hypersonic aircraft—vehicles that travel at speeds many times faster than sound. Analyzing how to fly a high-speed aircraft without overheating it can prevent structural failure while operating at maximum possible performance. The results shown in this section indicate that it is possible to operate at very high speeds in an aircraft while keeping peak vehicle temperature below our limits while saving fuel
Cultural Adaptation of the ACT Guide for Immigrant Community Members
Get PDFUndocumented immigrants face many challenges that can harm their mental health, such as anti- immigrant policies, the threat of deportation, and difficulty accessing mental health care. Online mental health programs can make mental health care more accessible. The ACT Guide is a self-paced online tool designed to help with anxiety and depression. While it has mainly been used by white college students, similar ACT-based programs have been effective for diverse communities worldwide. The first paper was focused on gathering feedback from community members and Latine psychologists. This was done in partnership with United We Dream (UWD) and the Latinx Immigrant Health Alliance (LIHA). Their feedback was used to make changes to the ACT Guide to make it more relatable and effective for undocumented young adults. The second paper was focused on testing the changed ACT Guide with a group of undocumented young adults. The results showed that it helped reduce depression, anxiety, stress, and feelings of being disconnected from personal values. These findings suggest that the changed ACT Guide could be a useful and accessible mental health resource for undocumented communities