{"id":16693,"date":"2021-03-11T10:48:20","date_gmt":"2021-03-11T08:48:20","guid":{"rendered":"https:\/\/acktar.com\/?p=16693"},"modified":"2023-04-29T14:40:25","modified_gmt":"2023-04-29T11:40:25","slug":"thermal-control-coatings","status":"publish","type":"post","link":"https:\/\/acktar.com\/thermal-control-coatings\/","title":{"rendered":"Black & White Thermal Control Coatings Comparison Experiment"},"content":{"rendered":"

ABSTRACT<\/h2>\n

In space applications, thermal control, emissivity and absorptivity are critical factors to the optimum performance of space vehicles or satellites.<\/p>\n

Thermal control coatings (TCC) are designed to have specific radiative properties that are tailored for different specific missions.<\/p>\n

For example, for solar orbiters, a radiative surface coated with a white coating having low absorptance and high emissivity is required.<\/p>\n

Usually, variously colored coatings from white to black are used for thermal design.<\/p>\n

In general, the function of TCC is to reduce external heat absorption and\/or to regulate radiant heat exchange between on-board equipment on spacecraft.<\/p>\n

Black coatings with high emissivity and absorptance values are usually required for high temperature applications.<\/p>\n

As heat absorbing surfaces, they provide high absorptivity and emissivity properties.<\/p>\n

For example surfaces with black coatings with high emissivity can be used in the internal parts for equalizing the internal temperature, whereas external surfaces of spacecraft can be coated with coatings having lower surface absorptivity and high emissivity.<\/p>\n

In this paper a brief overview of black and white thermal control coatings manufactured in USA, Russia, France and Israel and their main strengths for a range of space applications will be presented.<\/p>\n

The testing of these coatings in high temperature applications where the choice for coatings is drastically reduced will be discussed.<\/p>\n

Since the coatings in near-planetary, inter-planetary and planetary environments are exposed to UV solar radiation, charged particles, atomic oxygen, extreme temperature gradients induced by differences in relative sun exposure and dust it is very important to study their behavior in simulated LEO\/GEO and planetary conditions.<\/p>\n

The results of tests conducted on a number of coatings designed for LEO, GEO and interplanetary missions and the properties like atomic oxygen erosion resistance, surface conductivity, high temperature behaviour, BRDF characteristics, etc. will be presented.<\/p>\n

Influence of vacuum conditions on surface resistivity of inorganic coatings will be discussed.<\/p>\n

INTRODUCTION<\/h2>\n

In the last decade, space materials scientists worldwide expressed a concern about the problems of space durability of various external space materials and coatings interacting with the space environment.<\/p>\n

The influence on the space environment has become one of the major concerns due to the significantly extended longevity of space missions, international collaboration on various space projects, first of all, the International Space Station development and operation, as well as space exploration.<\/p>\n

The selection of the best, most durable materials is associated with the main subjects of space exploration, such as space mission\u2019s safety, spacecraft structures reliability and multi-million spending or savings.<\/p>\n

An international long-term research program was started in the 90th at ITL on comparative testing, durability evaluation, characterization and surface modification of advanced flight-proven space materials [1-4].<\/p>\n

These aspects of space materials\u2019 research become a special high-priority subject at the time of international collaboration and joint international agreements, for instance, such as the Agreement of 14 major space countries regarding their collaborative plans and efforts in the new era of global space exploration [5,6].<\/p>\n

The major objective of this paper is to provide a brief review of the impact of different simulated space environments on a variety of Russian, US, French, and Israeli functional thermal control coatings being used in space flights.<\/p>\n

EXPERIMENTAL<\/h2>\n

2.1 Materials<\/h3>\n

Thermal control coatings (TCC) from various sources were used in this program.<\/p>\n

The Russian materials included thermal control coatings manufactured by Kompozit Company in Russia.<\/p>\n

The western materials included advanced conductive and non-conductive last generation thermal control paints by Lord Corp. (USA), Alion (USA) and MAP (France) and some black TCC\u2019s from Acktar, Israel.<\/p>\n

A number of these TCC\u2019s, including the commercially available thermal control paints, and some experimental conductive (antistatic) thermal control coatings, have been treated and tested in ground-based testing facilities.<\/p>\n

The TCC\u2019s that were used in this study and some of their properties are presented in Tables 1 and 2.<\/p>\n

2.2 Testing and Characterization<\/h3>\n

The space environmental simulation testing and characterization of selected materials included:<\/p>\n