EQUULEUS

EQUULEUS is a 6U CubeSat project for cis-lunar region exploration, scheduled to be launched in 2020 by NASA’s Space Launch System (SLS) Exploration Mission 1 (EM-1). I mainly worked on thermal analysis and onboard software/simulator development for the thermal and propulsion subsystem.

EQUULEUS adopts a Water Resistojet Propulsion System for trajectory control for trajectory design control and angular momentum unloading. A large amount of heat required for vaporization and severe power constraint makes the thermal design and control tightly coupled with other subsystems. Through thermal vacuum tests and propulsion system operation tests followed by thermal analysis using Thermal Desktop models, we analyzed the feasibility of the entire mission phase.

In addition, due to the severe time-constraint and importance of the initial Delta-V maneuver phase, a robust FDIR (Fault Detection, Isolation, and Recovery) system is required. I was responsible for the FDIR design and software implementation for the thermal management system of both the bus-system and the propulsion module.

I also contributed to trajectory analysis related to halo orbit escape maneuvers at the end of the mission.

Figure 1. Flight Model Thermal Vacuum Chamber Test

Related Publications:

1. Funase, R., Ikari, S., Miyoshi, K., et al., (20th Author), “ Mission to Earth-Moon Lagrange Point by a 6U CubeSat: EQUULEUS”, IEEE Aerospace & Electro. Systems Magazine, Vol.35, No.3, pp.30-44, 2020 [paper]
2. Shibukawa, T., Matsushita, S., Iiyama, K., Ishikawa, A., Nishii, K., and Funase, R. “Flight Model Thermal Design and Validation for a 6U Deep Space Cubesat EQUULEUS”, 50th International Conference on Environmental Systems, Lisbon, Portugal, July, 2020. (conference postponed) [paper]
3. Dei Tos, D.A., Baresi, N., Chikazawa, T., Campagnola, S., Kawabata, Y., Iiyama, K., Kakihara, K., Ozaki, N., Funase, R., and Kawakatsu. Y., “Challenges and Solutions for the Trajectory Design of EQUULEUS”, 29th Workshop on Astrodynamics and Flight Mechanics, Kanagawa, Japan, July, 2019
4. Shibukawa, T., Matsushita, S., Iiyama, K., and Funase, R., “Reflection and Verification of Thermal Design under Tightly-Coupled Constraints to the 6U Deep Space CubeSat EQUULEUS”, 32nd International Symposium on Space Technology and Science, Fukui, Japan, 2019.
5. Matsushita, S., Shibukawa, T., Iiyama, K., and Funase, R. (2019), “Thermal Design and Validation for a 6U Cubesat EQUULEUS under Constraints Tightly Coupled with Orbital Design and Water Propulsion System”, 49th International Conference on Environmental Systems, Bostion, MA, The United States, 2019, [paper]