Deployable Solar Arrays for PocketQubes

Abstract

Research in miniaturization of satellite technology has enabled the development of a new class of satellites- PocketQubes. The extremely small form factor greatly limits power generation capabilities, with body-mounted arrays expected to generate around 1W average orbital power for the 3P size. Deployable solar arrays present an ideal solution for small satellites, enabling more demanding payloads onboard. Numerous designs for CubeSats have already been developed commercially and in academia.
This research focuses on adapting solar array designs available in literature to 3P PocketQubes, addressing their unique size, power and deployment constraints imposed by the deployer. A 4-panel array design in a wing configuration was designed, facilitating a peak power of 19.7 W. This was supported by a burn-wire mechanism and a torsion spring hinge. Structural analysis was conducted using LS-DYNA and ANSYS Mechanical to simulate deployment impact and launch vibrations, respectively. The analysis evaluated the design’s response to dynamic launch loads and mechanical impacts during deployment. The final assembly weight was 204.8 g, contributing to a specific power of 96.2 W/kg, comparable to many COTS deployable solutions for CubeSats. The procurement cost was found to be €1480 (excluding solar cell assemblies), and can be greatly lowered with higher order quantities for formation flying/distributed missions with multiple PocketQubes.
Additionally, this research examined the impact of solar array deployment configurations on power generation and orbital lifetime. Power generation was assessed using a simplified Python model, later verified through AGI STK simulations. Results indicated that the 𝛽 angle significantly influences power output across different configurations. Moreover, for peak 𝛽 angles representing noon-midnight and dusk-dawn orbits, seasonal variations were studied. This yielded an approximate 30% reduction during summer solstice for dusk-dawn orbits, but no visible change for noon-midnight orbits. For velocity aligned PocketQubes, configurations with panels mounted on the 5 × 5 cm face at a 135° deployment angle were found to be optimal. In contrast, for PocketQubes with pointing capabilities and high peak power requirements, the previously designed wing configuration was recommended.
The study of orbital lifetimes was facilitated by ESA’s DRAMA software and CROC was used to identify the minimum, average (random tumbling scenario), and maximum cross sections, contributing to a wide range of expected orbital lifetimes. In the velocity-aligned case, configurations featuring panels attached long edges (parallel to the drag force) yielded lifetimes suitable for long Earth observation missions. The latter configurations were found to be suited for shorter, technology demonstration missions. The launch date significantly impacted the results of the study, especially for configurations with higher ballistic coefficients. The results from this study however are highly idealistic, as the PocketQube angle of attack is expected to vary, largely influencing the drag area experienced. Assumptions regarding the drag coefficient and the use of NRLMSISE-00 drag model within DRAMA also limit the accuracy of the results, as seen when comparing the simulation and real observations from Delfi-PQ.