Reducing operational costs of thermal vacuum testing of spacecraft via gaseous nitrogen thermal conditioning technology

Many new thermal vacuum testing programs for ground testing of spacecraft require ensuring high accuracy temperature regime in a wide temperature range. Thermal vacuum tests are notable for significant material costs. Therefore, the requirement to reduce operating costs, including those associated with ensuring the temperature regime, is not less relevant. This explains the increased interest in promising energy-efficient technologies, one of which is based on the thermal conditioning of gaseous nitrogen. Systems with gaseous nitrogen thermal conditioning units have an optimal combination of operational and technical characteristics and, compared to systems where liquid nitrogen is poured into cryogenic screens, have lower consumption of liquid nitrogen and electrical energy, especially in stabilized temperature regime. The risk of contamination of the thermal vacuum chamber and the test object due to leaks of the liquid coolant is eliminated. Due to the fact that the properties of nitrogen quite accurately correspond to the ideal gas law, modeling of such systems is relatively simple, and the characteristics are predictable and stable. The article provides a brief analysis of the characteristics of gaseous nitrogen thermal conditioning units of two leading foreign manufacturers and the results of the practical application of four foreign manufactured thermal conditioning units with different characteristics in a typical thermal vacuum chamber. We considered the main directions of improving the characteristics of thermal conditioning units by foreign manufacturers. The conclusion is made about the high efficiency and economic feasibility of gaseous nitrogen thermal conditioning technology in most cases of thermal vacuum testing.