Session
Weekend Poster Session 2
Location
Utah State University, Logan, UT
Abstract
Reduced launch costs and increased interest from researchers and the public have enabled CubeSats to undergo significant evolution in the past decade, expanding their applications to include a broad range of fields such as communication, navigation, observation, education, and science demonstration. For a wide variety of nanosatellite missions ranging from Earth remote sensing to astronomy-related measurements and space debris tracking, the development of passive or active attitude control systems (PACS/AACS) is of great importance. Of the various attitude control and stabilization methods for small satellites, magnetic techniques such as magnetorquers and hysteresis rods offer modest pointing and detumbling capability while being ideal for satellites with low power budgets. Rigorously ground testing and optimizing these sub-systems in a laboratory setting requires transient 3-axis control of the magnetic field vector that reproduces the magnetic conditions of low-Earth orbit (LEO). However, doing so in a volume large enough for a CubeSat to tumble in (ex. on an air bearing) and maintaining a flight like high spatial homogeneity of the magnetic field, all while keeping costs down for accessibility to student groups in the CubeSat community, such as ours—the Princeton University TigerSats lab—presents a complex optimization challenge.
In this paper, we present a miniaturized, homogeneity-optimized 3-axis Helmholtz Cage of a modified squircle shape that can reproduce transient LEO magnetic fields for 1U satellites with high homogeneity ( < 1% B-field deviation) and for 2U satellites with modest homogeneity ( < 3% B-field deviation). We optimize our system for magnetic homogeneity by developing a computationally inexpensive simulation to compute the magnetic field produced by the Helmholtz Cage. Additionally, we present a novel perturbation analysis to predict the effects of imperfect coil winding. The theoretical simulation is verified to show excellent agreement with the experimental magnetic field. We also present the circuitry for a closed-loop system to simulate transient magnetic fields. The entire system is highly accessible due to the low material costs, documentation of the coil design process, and scalability to accommodate larger CubeSat sizes. We emphasize the merit of presenting a ground testing system that is affordable and implementable for most student groups as comprehensive in-house qualification is a rich educational opportunity that is often under-utilized.
SSC23-WP2-40 Poster
A Low-Cost, Miniaturized, Homogeneity-Optimized Helmholtz Cage for CubeSat Attitude Control Ground Testing
Utah State University, Logan, UT
Reduced launch costs and increased interest from researchers and the public have enabled CubeSats to undergo significant evolution in the past decade, expanding their applications to include a broad range of fields such as communication, navigation, observation, education, and science demonstration. For a wide variety of nanosatellite missions ranging from Earth remote sensing to astronomy-related measurements and space debris tracking, the development of passive or active attitude control systems (PACS/AACS) is of great importance. Of the various attitude control and stabilization methods for small satellites, magnetic techniques such as magnetorquers and hysteresis rods offer modest pointing and detumbling capability while being ideal for satellites with low power budgets. Rigorously ground testing and optimizing these sub-systems in a laboratory setting requires transient 3-axis control of the magnetic field vector that reproduces the magnetic conditions of low-Earth orbit (LEO). However, doing so in a volume large enough for a CubeSat to tumble in (ex. on an air bearing) and maintaining a flight like high spatial homogeneity of the magnetic field, all while keeping costs down for accessibility to student groups in the CubeSat community, such as ours—the Princeton University TigerSats lab—presents a complex optimization challenge.
In this paper, we present a miniaturized, homogeneity-optimized 3-axis Helmholtz Cage of a modified squircle shape that can reproduce transient LEO magnetic fields for 1U satellites with high homogeneity ( < 1% B-field deviation) and for 2U satellites with modest homogeneity ( < 3% B-field deviation). We optimize our system for magnetic homogeneity by developing a computationally inexpensive simulation to compute the magnetic field produced by the Helmholtz Cage. Additionally, we present a novel perturbation analysis to predict the effects of imperfect coil winding. The theoretical simulation is verified to show excellent agreement with the experimental magnetic field. We also present the circuitry for a closed-loop system to simulate transient magnetic fields. The entire system is highly accessible due to the low material costs, documentation of the coil design process, and scalability to accommodate larger CubeSat sizes. We emphasize the merit of presenting a ground testing system that is affordable and implementable for most student groups as comprehensive in-house qualification is a rich educational opportunity that is often under-utilized.
