Abstract
The optical solar reflector is basically a mirror of second surface with low absorptivity/emissivity ratio and negligible degradation in the space environment, which makes it an excellent coating for thermal control of satellites. It works as a radiator and is used in particular parts of the external surfaces of the satellites in order to reject the undesirable heat to the deep space. In the Brazilian Space Programs, the radiators of the satellites are generally painted with special white paints in order to reject heat instead of the use of optical solar reflector. The problem of white-ink radiators is the high degradation of the thermo-optical properties that happen over the useful lives. Thus, a process of manufacturing and assembly of optical solar reflector was developed in Brazil. To validate this process in terms of mechanical and thermal properties, 3 types of optical solar reflector radiators were manufactured, and their absorptivity and emissivity properties at the temperature of 23 °C were measured. Optical solar reflector coupons were mounted on aluminum plates to perform vibration, thermal vacuum and thermal-shock tests. A study was also done to optimize the thickness of the glue to fix the structure of the satellite on the optical solar reflector. It showed an excellent environmental stability and maintained its thermo-optical characteristics after the tests.
Highlights
Artificial satellites are equipment sent into space in order to perform a certain task, such as: meteorological studies, telecommunications, data collection for scientific studies, etc
The satellite is exposed to extreme thermal conditions such as solar radiation, radiation that comes from the Earth, and a strong heat sink that is deep space, where the fund temperature is 4 K
One of the materials commonly used to coat the satellite is the thermal blanket known as multi-layer insulation (MLI) (Nagano et al 2011)
Summary
Artificial satellites are equipment sent into space in order to perform a certain task, such as: meteorological studies, telecommunications, data collection for scientific studies, etc. Random Vibration Test The samples were subjected to random vibration according to the levels specified by the MIL-STD 883 — Method 2026 — K condition (Table 4) This test is intended to check the performance and mechanical strength of the bonding of the coverslips on OSR aluminum plate as well as the strength of adhesion of thin films of metal deposited on the borosilicate. Any problem could be magnified during the thermal vacuum test and could be checked after this This test aimed to verify possible cracks caused by OSR differential thermo-dilation, delamination of thin films of the metal borosilicate coverslip glass, as well as problems related to assembly with air bubbles in the glue, which could expand due vacuum and damage the radiator. This procedure aimed at reducing the duration of the test, facilitating the chamber operation (Almeida et al 2006)
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