Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Analysis of a thermal vacuum chamber project for nanosatellites tests
Submission Author:
Damylle Donati , SC , Brazil
Co-Authors:
Vitória Tessari, Lucas Silva dos Santos, Carlos Eduardo Bibow Corrêa, Damylle Donati, kleber paiva, Egemael Viesser, Talita Possamai, Renato Oba
Presenter: Vitória Tessari
doi://10.26678/ABCM.COBEM2023.COB2023-0445
Abstract
To guarantee that a nanosatellite complies with operating requirements, taking into account the launch, commissioning, and operation phases, it must undergo a series of qualification tests, whether requested by the launch vehicle supplier or the project team. Thermal tests are critical to the design of a nanosatellite, and some are part of the launch qualification list. Among such tests, the bake-out and thermal cycling tests stand out, which simulate the sudden increase in temperature and the life cycle of the satellite in the orbit of interest, sometimes receiving direct radiation from the sun, sometimes in contact with deep space. However, tests in vacuum chambers, a device that simulates extreme temperatures and vacuum conditions, are considerably expensive, making it impossible for project teams with low budgets to carry out such tests before the qualification phase, which causes insecurity regarding the integrity of the product, as there may not be enough time for changes in the event of a breakdown. To overcome this situation, this study presents the design characteristics of a low-cost vacuum-thermal chamber used for testing during the development phases of a nanosatellite. Its conceptual design, structural and insulation characteristics, and thermodynamic behavior are presented. The chamber can reach 1x10$^{-5}$ mbar of internal pressure, a maximum temperature of 120$^\circ$C and a minimum temperature of -10$^\circ$C for isopropyl alcohol as a refrigerant. To ensure the effectiveness of the simulation of the problem, this study presents an isothermal analysis of the chamber developed through the acquisition of temperature data in a cage that models the standardized dimensions for CubeSats. Two configurations are compared: the chamber with a glass window and a reflective metal door, releasing radiation to the external environment and applying two hatches in the shroud for isolation. Both configurations were tested in two situations: cooling and heating. In the cooling test, the configuration with hatches presented lower heat loss and more significant temperature uniformity. Meanwhile, the configuration without the hatches presented a sudden temperature drop along the length of the cage, with minimum values in the central points. The variation of the central point among configurations was approximately 6$^\circ$C. However, both configurations showed similar behaviors in the heating test, with more significant heating near the door in the configuration without hatches. The results indicate that the chamber performs well in testing objects with small dimensions, such as CubeSats 1U, picosatellites, and CanSats. For the CubeSats 6U analysis, modifications regarding the heat source uniformity and thermal insulation must be made.
Keywords
Vacuum Chamber, Thermal Tests, cubesat, Thermal Control
