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Development of a Tool for Planning Fuel-Optimized Collision Avoidance Maneuvers
Get PDFThe need for collision avoidance maneuvers is expected to rise due to growing congestion in low-Earth orbit. This paper presents the development of a tool to automate the generation of collision avoidance maneuvers in response to conjunction events. The tool presented has allowed the Space Flight Laboratory (SFL) to eliminate concerns associated with human error, while concurrently addressing the expected increase in the need for these maneuvers without needing to impose any additional burden on flight dynamics engineers. The automation of this task has reduced the hands-on time required by over 80% when compared to the pre-existing workflow.
If the risk associated with an identified conjunction event is too high, a collision avoidance maneuver must be planned to reduce the probability of collision. This tool first assesses the safety of the event assuming no action is taken. The optimal thrust axis, thrust time, and thrust ∆v are selected to design a fuel-optimized collision avoidance maneuver to improve the safety of the conjunction event such that the post-maneuver probability of collision is below a user-configurable threshold. The tool then validates the selected maneuver through simulation to assess the post-maneuver safety of the conjunction event. The final step of the tool is to generate an orbit ephemeris message and a set of time-tag commands. These files are ready for immediate use by operators, requiring no additional processing or intermediary steps.
This paper provides justification for the various criteria used to design fuel-optimal collision avoidance maneuvers, including discussion on why alternative approaches are less fuel optimal. The end-to-end operation of the tool has been validated through on-orbit operations, with the tool having been used to design 14 successful maneuvers in support of over 10 active missions. The tool presented therefore provides a robust comprehensive solution for generating fuel-optimal collision avoidance maneuvers. The continued development of automated tools such as the one presented is going to be necessary to address the increasing complexity of space traffic coordination, and the increasing complexity of the space environment as a whole
Deploying Post Quantum Cryptography on Newspace Satellites
No full textWe describe and implement a new key exchange protocol combining both Post Quantum Cryptography (PQC) and Elliptic Curve Cryptography (ECC). The protocol is designed to allow for authenticated key exchanges with a single satellite. The Triple Key Encapsulation Mechanism (KEM) protocol is designed to be secure against both classical and quantum attackers and retains its full security even if one of the two cryptographic schemes is broken. The protocol was implemented on two generations of Berlin Space Technology (BST) On Board Computers (OBC) and tested on the AFR small satellite in low earth orbit using an In Orbit Demonstrator (IOD) board of the new BST OBC. We discuss some of the challenges PQC poses for low performance systems and satellites in general and outline some of the strategies employed to overcome them
PEEK-Guided Neural Network Pruning for Deployment on Low SWaP Hardware
No full textDeploying deep learning models onboard spacecraft is limited by strict size, weight, power (SWaP), and bandwidth constraints. Standard object detection networks like YOLO or Faster R-CNN are too computationally heavy for real-time use in space. We present a pruning framework using PEEK (Probabilistic Explanations for Entropic Knowledge extraction), an entropy-based interpretability method that pinpoints low-information layers for removal. Applied to YOLOv5 for Rendezvous, Proximity Operations, and Docking (RPOD), this approach cuts model size by up to 30% and compute cost by 25%, with only minor accuracy trade-offs—enabling faster, reliable detection on low-SWaP spacecraft platforms
Development Status of Flight Model of ARICA-2
No full textARICA-2 (AGU Remote Innovative CubeSat Alert system -2) is a 2U CubeSat developed in AGU (Aoyama Gakuin University) in JAPAN. ARICA-2 was selected as the as the JAXA Innovative Satellite Technology Demonstration-4 and is scheduled for launch in Japanese fiscal year 2025. The mission objective of this satellite is to demonstrate the real-time alert system of sudden astronomical phenomena, such as gamma-ray bursts (GRBs). Observation of GRBs is challenging because it is difficult to predict location and time of occurrences and its extremely short duration. So, it is necessary to alert immediately for tracing observations of GRBs from the other observational equipment. ARICA-2 is the successor to ARICA, a 1U CubeSat launched by JAXA rocket in 2021. However, ARICA has never established the communication. ARICA-2 has three communication devices, two types of commercial satellite communication devices and a UHF (Ultra High Frequency) communication device. As ARICA did, ARICA-2 tries to demonstrate the real-time alert system by using commercial satellite network services. Commercial satellite communication devices are relatively inexpensive and easy to obtain. So, this demonstration is expected to promote research on sudden astronomical phenomena. Additionally, we decided to use UHF communication device, magnetorquers to attitude control system and Spresense, which is SONY’s low-power micro controller board, for on-board computer on ARICA-2 as a reflection of ARICA. And ARICA-2 is equipped with two types of gamma-ray detectors larger than that of ARICA
[M]otherhood: Navigating Work-Family Constraints and Strategies in Pink-Collar Jobs
No full textWorking mothers continue to confront cultural norms and workplace practices that frame paid labor as incompatible with caregiving. In the workplace, these norms often result in motherhood bias and discrimination due to the incompatibility between norms of the ‘ideal worker’ and the ‘ideal mother’ (Acker 2006; Williams, Blair-Loy and Berdahl 2013). This tension is especially acute in pink-collar jobs, women-dominated occupations in service and care sectors, which are often mischaracterized as mother- friendly despite offering limited flexibility, low pay, and minimal structural support (Sartor, Lange, and Tröster 2023; Deming 2022; Ervin et al. 2022). While prior research has explored the motherhood penalty in elite white-collar professions (Stone 2007), the experiences of mothers in pink-collar work remain underexamined, particularly at the intersection of race, gender, and class.
This study uses intersectionality as a theoretical and methodological lens to explore how mothers navigate structural constraints and cultural expectations in pink- collar jobs. Drawing on eighteen semi-structured interviews, I examine how racialized labor expectations, motherhood discrimination, and institutional neglect shape both the constraints mothers face and the strategies they employ. I ask: (1) How do mothers navigate pink-collar jobs? and (2) How do gender, race, and class shape the constraints, strategies, and needs of mothers in pink-collar jobs?
Findings demonstrate that pink-collar jobs are not inherently mother-friendly. Instead, these occupations often demand emotional, physical, and mental labor without reciprocating care or accommodation. Mothers report facing wage penalties, limited autonomy, pregnancy discrimination, inadequate breastfeeding accommodations, and work-life imbalance.
By centering both white mothers and mothers of color, this study reveals how motherhood in pink-collar work is shaped by overlapping systems of oppression. The findings call for structural changes in workplace policy, including paid leave, employer flexibility, affordable childcare, and protections against racial and maternal discrimination. This research contributes to sociological understandings of gendered labor by demonstrating that caregiving work is not only feminized, but also racialized- and that any meaningful support for mothers must confront these intersecting inequalities
Utilizing Software-Defined Radio Technology in the Development and Operation of a Backup S-Band Ground Station for the ONGLAISAT CubeSat
Get PDFThe ONGLAISAT CubeSat, jointly developed by Taiwan Space Agency (TASA), the University of Tokyo, and Ark Edge Space, was launched in Q4 2024 to conduct optical remote sensing. To support downlink operations via S-band, National Central University (NCU) established a backup ground station. A complete lifecycle plan was implemented, incorporating Software Defined Radio (SDR)-based signal analysis, CCSDS-compatible telemetry visualization via WINGS, and end-to-end RF testing. Initial on-orbit signals were successfully received in Q1 2025. Doppler shift and power fluctuation analysis demonstrated system performance and operational readiness. In addition, signal comparison can serve as an alternative method for determining the satellite\u27s orbit and attitude. This work highlights the role of SDR in enhancing ground station flexibility and reinforces the value of international collaboration in small satellite missions
RHOK-SAT: Investigating Perovskite Solar Cell Performance and Degradation in Low Earth Orbit Through a 1U CubeSat
Get PDFRHOK-SAT is a 1U CubeSat scheduled to launch in September 2025 aboard a resupply mission to the International Space Station (ISS) through NASA’s CubeSat Launch Initiative (CSLI) program. Its mission is to characterize the performance and degradation of six experimental perovskite solar cells in low Earth orbit for 12 months. Characterization consists of current-voltage measurement taken by one dedicated microcontroller per solar cell. Measurements are performed when the cells are in direct sunlight, determined via a quadrant photodiode. A silver-alloyed copper indium gallium selenide (ACIGS) solar cell serves as a reference for comparative analysis due to its well-characterized behavior. Each solar cell is also equipped with a resistance temperature detector (RTD) to provide complementary thermal data to every measurement. RHOK-SAT’s payload is mounted using two printed circuit boards (PCBs), with the solar cells mounted beneath a non-conductive anodized top plate featuring apertures.
The satellite’s flight software (FSW), running on FreeRTOS, manages experiment execution, data management, communications, and system health. Supported by a full-duplex transceiver on board, the software defines a robust communication pipeline for experimental data downlink through an acknowledgment system with the commanding ground station. Additionally, interrupt-driven timers allow experimental data downlink to be automated and received by ground stations across the globe. As a fail-safe mechanism, the FSW can also be updated in flight, providing further tolerance against unanticipated behavior.
To monitor system health, RHOK-SAT periodically transmits telemetry data, including battery level, tumbling rate, and solar panel temperature, which can be visualized on a Grafana dashboard. RHOK-SAT relies on two ground station systems. The primary, commanding ground station, located at Rhodes College, is equipped to transmit commands to the satellite and receive data. Additionally, RHOK-SAT is part of the SatNOGS network, a global open-source satellite ground station system. Through SatNOGS, ground stations worldwide can be utilized to receive data, significantly increasing downlink capability.
RHOK-SAT is a collaborative project involving Rhodes College, the Photovoltaic Materials and Devices Group (formerly at the University of Oklahoma, now at the University at Buffalo), the National Renewable Energy Laboratory (NREL), and the Aerospace Corporation
The Auroral X-Ray Imager (AXIS)
Get PDFThe interaction of the solar wind with the Earth is a subject of significant study. One phenomenon is the occurrence of aurorae at the polar regions, resulting from the interaction of particles in the solar wind with the atmosphere, often giving light shows which captures the publics’ imagination. These energetic interactions also extend to X-ray wavelengths. Whilst aurorae have been studied for generations in the visible, the X-ray emission of aurorae has only been observed by a couple of spacecraft, with a paucity of data. There are only a couple of instances of emission intensity having been measured, but without any spectral information.
The Auroral X-ray Imaging Spectrometer (AXIS) is an instrument concept which is being developed by the Indian Space Research Organisation’s (ISRO) Space Astronomy Group (URSC) with academic and industrial collaborators from the UK funded by the UK Space Agency (UKSA) as part of its International Bilateral Fund (IBF). The AXIS instrument aims to provide world-first measurements of spectral information from the Earth’s aurorae in the 0.3 – 3 keV band, enabling study of emission from the key sources: X-ray fluorescence from atmospheric elements, bremsstrahlung and solar wind charge exchange (SWCX). The urgency to develop this instrument results from a desire to perform simultaneous measurements studying the impact of the solar wind with the ESA-CAS mission SMILE. SMILE is due for launch from Kourou with a January-September 2026 launch window. The Soft X-ray Imager (SXI) of SMILE will study the interaction of the solar wind with the Earth’s magnetosphere in the same soft X-ray band, and simultaneous observations from both high orbit (SMILE/SXI) and LEO (AXIS) would provide a unique dataset for scientific study. To achieve this timely simultaneous observation capability, ISRO’s IMS-1 platform (Indian Micro-Satellite), would be utilised which is a 100kg platform capable of supporting a 30kg instrument complement.
AXIS will have two X-ray pinhole cameras with a combined 140o FOV and provide a technology demonstration of new X-ray CMOS image sensor (CIS) technology being developed for ESAs Theseus mission concept, together with a new compact scientific camera drive system using the CubeSat standards. These new technologies will enable X-ray photon counting with spectroscopic information giving \u3c 100 eV resolution at 1 keV, enabling separation of the emissions from the atmospheric elements; oxygen, nitrogen, etc. Uniquely, this new instrument concept will enable such X-ray photon counting and spectroscopy whilst operating at a temperature of around 0oC (compared to similar X-ray instruments requiring sensor cooling between -112oC (SMILE/SXI) to -130oC (XMM/EPIC). This step-change in performance is achieved using a combination of radiation hardness, low dark current and high frame rate of CIS, and will undoubtedly find many spin-off applications in other space instruments and missions.
We will describe the mission concept and it’s timeliness with SMILE, and outline the capabilities of the IMS-2, before giving detailed description of the AXIS instrument, its objectives and the key technologies being used to achieve its performance, together with test data from X-ray test (lab and synchrotron) and gamma and proton qualification.
Initially, the overall mission concept and previous results science results will be described, and how the mission concept aligns closely with ESA’s SMILE mission. The capabilities of the IMS-S launcher will be outlined, before a detailed description of the AXIS instrument is provided, along with its key scientific objectives and key technologies being used to achieve its performance. Finally, experimental test data and results acquired from laboratory and synchrotron testing will be shown
Demonstration of X-Ray Pulsar-Based Navigation with the CubeSat Astronomical Observatory NinjaSat
Get PDFThis study examines the feasibility of X-ray pulsar navigation with the CubeSat. We developed NinjaSat equipped with gas X-ray detectors sensitive to 2–50 keV with effective area of 16 cm2 at 6 keV. We estimate position and velocity of NinjaSat from Crab pulsar observation data by orbital estimation method based on “Significance Enhancement of Pulse-profile with Orbit-dynamics”. As a result, the estimated position accuracy was within 59 km
COTS Implementation of Magnetorquer-Only CubeSat Spin Stabilization
Get PDFThis paper presents the implementation of CubeSat attitude control algorithms on commercial off the shelf (COTS) hardware. Cornell’s Alpha CubeSat seeks to spin-stabilize using only magnetorquer outputs and IMU inputs. Extensive software development and testing is carried out to overcome these hardware limitations. This paper shares tools, techniques, and niche considerations when bringing the control algorithm from simulation to hardware-in-the-loop (HITL) testing with embedded flight software. In-depth approaches for magnetometer filtering are discussed, along with software implementation decisions for safe mission operations