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To Bee or Not to Bee: Investigating Pesticide Behavior Inside and Outside of Semi-Field Cages
No full textBees play an important role in ecosystems and food production through pollination. One such bee, the alfalfa leaf cutting bee (ALCB) is a very efficient pollinator and is essential in alfalfa seed production. However, bees face increasing harm, most notably due to the deleterious effect of pesticides used in agriculture, and much research is dedicated to investigating the extent of effects that pesticides have on different bee populations. One common tool used to study the effects of pesticide exposure on bees is semi-field cages. These cages have some key advantages, such as restricting bee foraging to plots sprayed with pesticides and simulating agroecosystem conditions. However, these semi-field studies operate under the assumption that the environmental conditions are the same and that pesticides loss will occur at the same rate. To test this assumption, field experiments were conducted. These experiments were conducted by spraying three common-use pesticides on alfalfa leaves inside and outside of field cages and determining the concentrations of pesticides on the leaves over a period of seven days while monitoring the meteorological conditions in each environment. Upon completion of this study, it was found and concluded that there were no significant differences in pesticide loss rates, suggesting that the pesticides used in this study did in fact behave similarly inside and outside of semi-field cages during these experiments
A Radio Payload for In-Space Sub-Terahertz Communications
Get PDFThis paper presents the first fully integrated design of a CubeSat-compatible sub-terahertz (sub-THz) radio payload for in-space communications at 225 GHz. Addressing the growing congestion in traditional RF bands and the limitations of Free Space Optical systems, the proposed system leverages recent breakthroughs in compact high-frequency front-ends, horn antenna arrays, and RFSoC-based digital processing to unlock multi-GHz bandwidths in the underutilized sub-THz spectrum. A detailed feasibility study confirms link closure from low Earth orbit using state-of-the-art components, and the payload’s architecture is engineered for real-time high-speed uplink/downlink under stringent CubeSat size, weight, and power (SWaP) constraints. The proposed payload will fly aboard the TeraLink CubeSat mission, marking a critical step toward operational sub-THz satellite links and ushering in a new era of broadband, high-frequency space communications
Consolidated Simultaneous Ranging and Clock Synchronization With Application to Positioning in Cis-Lunar Space
No full textThe AOWR scheme functions as a set of transceivers connecting two entities: the ground station and the spacecraft. The phase difference information obtained from both sides intrinsically contains data related not only to the range but also to the clock difference simultaneously. The AOWR scheme can synchronize the clock onboard the spacecraft regardless of the distance. In cis-lunar space due to poor geometric configurations, until the position is determined, the clock difference cannot be established. It drastically improves and reduces the dilution-of-precision index. The paper will present the outcomes confirmed through demonstration experiments utilizing hybrid devices related to the GNSS and the AOWR schemes with software-defined radio technology
ROSISat - The Radiation Orbital Shielding Investigation Satellite
Get PDFThe Radiation Orbital Shielding Investigation Satellite (ROSISat) is an ongoing 1U CubeSat project designed to study the effectiveness of various materials as shielding against single-event upsets and effects on computer memory modules in Earth orbit. ROSISat is a student project managed under the Embry-Riddle Orbital Research Association (ERORA), a registered student organization at Embry-Riddle Aeronautical University in Daytona Beach, Florida. It is one of three projects from ERORA presented at this conference, alongside tBEARR and SATLASS. ROSISat aims to be the first of ERORA’s projects to be launched and operational in LEO, serving to develop CubeSat flight heritage at ERAU
Attitude Control of a CubeSat for the Lunar Navigation Satellite System (LNSS) Using Thrusters and Reaction Wheels
Get PDFPoster presented during the 2025 SmallSat Conference
The Potential of Small Optical Isolators for LEO Satellite Equipment
Get PDFPoster presented during the 2025 SmallSat Conference
Development of an Open-Source Spacecraft Bus for the PULSE-A CubeSat
Get PDFThe undergraduate-led Polarization-modUlated Laser Satellite Experiment (PULSE-A) at the University of Chicago seeks to demonstrate the feasibility of circular polarization shift keyed satellite-to-ground laser communication. Free-space optical communications offer significantly improved data rates and lower power requirements than radio frequency communications for a similar form factor, which makes optical communications of particular interest for future satellite missions as on-orbit data collection rates increase. PULSE-A’s low-cost open-source bus serves as the backbone of the mission and has been designed in tandem with the Payload, with design driven by strict requirements for pointing accuracy, component alignment, power demand, and thermal stability. This work presents the design and testing of the PULSE-A bus.
The spacecraft bus was designed to fill two major needs, (1) to meet the requirements of the PULSE-A mission, and (2) to be easily configurable for future missions that desire enhanced capabilities over other low-cost open-source designs (including follow-on missions to PULSE-A). At its core, the bus features dual Beagle-Bone Black Industrial compute units—selected for their flight heritage—integrated via a PC/104 header standard. The open-source power system builds on existing designs from Hawai’i Space Flight Laboratory’s Artemis CubeSat kit and Stanford’s PyCubed kit, adapted to meet PULSE-A’s demanding requirements. While these kits are designed for low-power, modular payloads, PULSE-A’s power system is capable of continuous higher-power operation while preserving the modularity fundamental to these open-source designs. PULSE-A implements Goddard Space Flight Center’s core Flight System (cFS), which takes a modular software architecture approach and is built in C, unlike Artemis, which relies on Arduino C++, and Py-Cubed, which was developed in Python. The use of C as the primary language aligns with the expertise of the University of Chicago’s Computer Science department, allowing for ease of development by PULSE-A’s undergraduate flight software team. The stack is designed to interface with commercial off-the-shelf Attitude Determination and Control Systems that implement their own control algorithms to ease development of the optical tracking system.
The CubeSat structure utilizes Gran Systems’ 3U frame, modified to accommodate openings for various ports and deployable components including sensors, antennas and solar panels. Inside, the avionics stack uses the PC/104 standard quad rails which terminate in PULSE-A’s custom-designed Payload Box that houses all of the Payload components and optical fiber runs. The Payload-to-bus interface enables precise thermal control of sensitive components through careful selection of interface screw sizes and pad materials. Lastly, the optical mounts and Payload box are designed to be easily manufacturable in most university machine shops, further contributing to their ease-of-implementation. This work also covers the techniques and iterative engineering processes used to develop the thermal control and dissipation mechanisms for the specific requirements, under volume, mass and temperature-range constraints
Efficient Adaptive Thruster Control Strategies for Nanosatellite Attitude Control
Get PDFThis work explores the use of online estimation techniques to enhance advanced thruster-only attitude control strategies. Classical fixed-gain feedback control and newer model predictive control (MPC) based approaches all suffer from reduced efficiency or performance when the system parameters deviate from their nominal values. By incorporating optimal estimation techniques, this can be avoided and deviations from nominal values can be leveraged for fault detection, isolation, and recovery (FDIR).
Specifically, this work investigates the use of extended Kalman filters (EKF) to estimate parameters such as thruster torque and disturbances in real time, using satellite attitude measurements and known control inputs. In addition to providing nominal parameter estimates, this approach also yields uncertainty estimates, which can be used to provide stochastic robustness guarantees.
High-fidelity simulations are performed with varying levels of noise introduced, and using a variety of different fine pointing and slewing attitude control schemes, to assess the effectiveness of the developed adaptive parameter estimation techniques. This is done by studying the effects on total propellant use, stability of control algorithms, and the convergence of the parameter estimates
Magnetic Balancing for Microvibration Reduction in Passive Magnetic Bearings for Smallsat Reaction Wheels
No full textPoster presented during the 2025 SmallSat Conference
OrigamiSat-2: 3U CubeSat Demonstrator for Two-Layer Pop-Up Origami Deployable Membrane Reflectarray Antenna
No full textPoster presented during the 2025 SmallSat Conference