Advanced Thermal Control Coatings for Use in Low Earth Orbit

Space technology has been developed for frontier exploration not only in low-earth orbit environment but also beyond the earth orbit to the Moon and Mars, where material resources might be strongly restricted and almost impossible to be resupplied from the earth for distant and long-term missions performance toward “long-stays of humans in space”. For performing such long-term space explorations, none would be enough to develop technologies with resources only from the earth; it should be required to utilize resources on other places with different nature of the earth, i.e., in-situ resource utilization. One of important challenges of lunar in-situ resource utilization is thermal control of spacecraft on lunar surface for long-lunar durations. Such thermal control under “long-term field operation” would be solved by “thermal wadis” studied as a part of sustainable researches on overnight survivals such as lunar-night. The resources such as metal oxides that exist on planets or satellites could be refined, and utilized as a supply of heat energy, where combustion synthesis can stand as a hopeful technology for such requirements. The combustion synthesis technology is mainly characterized with generation of high-temperature, spontaneous propagation of reaction, rapid synthesis and high operability under various influences with centrifugal-force, low-gravity and high vacuum. These concepts, technologies and hardware would be applicable to both the Moon and Mars, and these capabilities might achieve the maximum benefits of in-situ resource utilization with the aid of combustion synthesis applications. The present paper mainly concerns the combustion synthesis technologies for sustainable lunar overnight survivals by focusing on “potential precursor synthesis and formation”, “in-situ resource utilization in extreme environments” and “exergy loss minimization with efficient energy conversion”.

Download Full-text

Thermal Control Materials and Coatings Currently Being Developed in France for Use in Low Earth Orbit

Protection of Space Materials from the Space Environment - Space Technology Proceedings ◽

10.1007/978-94-010-0714-6_18 ◽

2001 ◽

pp. 235-242

Author(s):

F. Guerard ◽

J. C. Guillaumon

Keyword(s):

Thermal Control ◽

Low Earth Orbit ◽

Earth Orbit

Download Full-text

Property changes in materials due to atomic oxygen in the low Earth orbit

CEAS Space Journal ◽

10.1007/s12567-021-00376-2 ◽

2021 ◽

Author(s):

Aki Goto ◽

Kaori Umeda ◽

Kazuki Yukumatsu ◽

Yugo Kimoto

Keyword(s):

Photoelectron Spectroscopy ◽

Atomic Oxygen ◽

Surface Reactions ◽

Ccd Camera ◽

Polymeric Materials ◽

Thermal Control ◽

Polyimide Film ◽

Low Earth Orbit ◽

Earth Orbit ◽

Exposure Experiment

AbstractWe expect satellites at altitude below 300 km, very low Earth orbit (VLEO), making observations of the Earth at optical wavelength with increasingly higher resolution. The density of atomic oxygen (AO) at VLEO is significantly higher than that at LEO; severe degradation of spacecraft materials (polymers) due to the high-flux AO is a serious concern. To clarify VLEO environmental effects on spacecraft materials, we designed the Material Degradation Monitor (MDM) and MDM2 missions. The MDM is a material exposure experiment onboard the Super Low-Altitude Test Satellite (SLATS). It aims to understand reactions and degradation of polymeric materials depending on AO fluence in VLEO. In the MDM, samples of spacecraft material were exposed at altitude of 160–560 km; their degradation behaviors were observed optically by a CCD camera for 1.8 years. The MDM2 is a material exposure experiment onboard the International Space Station (ISS) and aims to correctly understand surface reactions and degradation of the same samples used in the MDM at a given AO fluence. In the MDM2, the samples were exposed at altitude of 400 km for 1 year and then returned to Earth for analysis. Based on the results from both missions, we will help in the molecular design of more-durable materials, and establish design standards for future VLEO satellites. This study aims to quantitatively understand the surface reactions and degradation of the 11 types of thermal control materials exposed on the ISS in the MDM2. Five types of multilayer insulation (MLI) films (three types of Si-containing AO protective materials (a silsesquioxane-(SQ-) containing coated polyimide film, two types of polysiloxane-block polyimide (BSF-30) films), an ITO-coated polyimide film, and a Beta Cloth), and flexible optical solar reflectors (flexible OSRs) were found to have a high durability against erosion by AO. This was determined by measuring their loss of mass and thermo-optical properties. The Ag/Inconel layer’s discoloration and peeling were observed for three types of FEP/Ag films as determined by the Ag layer’s oxidation by AO. Also, X-ray photoelectron spectroscopy (XPS) showed that reactions of the Si-containing materials, the SQ-coated polyimide film and the BSF-30 film, form a layer of silica that protects against AO. Even though the concentration of Si in the SQ-coating is the same or greater than in the BSF-30 film, the amount of the SQ-coating that reacted was larger than that of the BSF-30 film under the same AO fluence. Moreover, the effective ability of the UV-shielding coating, composed of ITO and CeO2 coated onto one of the BSF-30 films, was demonstrated by UV–Vis spectrometry. Its sufficient AO protection was confirmed by mass measurements, XPS analyses, and FE-SEM observations.

Download Full-text