A simplified manned spacecraft cabin air temperature control model and its verification

Abstract

Cabin air temperature control is a vital function of manned spacecraft environmental and thermal control systems, which is a key factor influencing orbited astronaut comfort. A manned spacecraft cabin air temperature and humidity control system design is provide in this paper, which is based on combination of single phase fluid loop and cabin ventilation. A simplified, semi-active cabin air temperature control model is developed based on experimental and analyzed results. The research result shows that cabin air temperature is mainly determined by cabin heat load, heat transferred by condensing heat exchanger and cabin heat loss. Especially, cabin heat loss is the key factor influencing cabin air temperature control and is too complicated to be determined by analyzing. The characteristic of cabin heat loss is achieved by ground test and a linear behavior between the cabin heat loss and cabin air temperature is developed within limited cabin air temperature range. Based on the developed air temperature control model, the orbiting working modes of the temperature and humidity control system can be determined for different set cabin air temperature, including the air flow rate through condensing heat exchanger (the ventilation valve angle), the set temperature of single phase fluid loop. The determined working modes based on the simplified cabin air temperature control model have been applied during the orbit flight. The flight data show that cabin air temperature can be adjusted between 10-26 ℃ ℃℃ ℃ within ±1 ℃ precision. The validity of the cabin air temperature control model is verified by the flight.