The space suit worn by Shenzhou crews during the launch and re-entry is a Chinese copy of the Russian Sokol-KV2 (Cокол: Falcon), which was manufactured by NPP Zvezda and worn by early Soyuz crews. China obtained examples of the Sokol-K in the 1990s and developed its own space suit on its basis. Official Chinese publications refer to this space suit as “Intra-Vehicular Activity Space Suit” (舱内航天服).
The space suit is 10kg in mass, and consists of three layers. The inner form-fitting undergarment is designed for cooling and ventilation. It removes excess body heat from the wearer using the flow of air. This design is less efficient than the liquid cooling and ventilation garment seen on Western-designed space suit. The middle layer is made of rubberised nylon in order to keep a stable internal pressure. The outer layer is made of white nylon canvas to provide protection for inner layers. Grey leather outer boots are integrated with the suit but the gloves are removable.
The suit has adjustment straps on the arms, legs, chest and abdomen. A large pressure relief valve located at the centre of the chest regulates the pressure inside the suit. A pressure gauge and a wrist watch are worn on the left arm. Communication and electric cables are mounted on the right abdomen of the suit. There are two separate hoses for oxygen supply and exhaustion located on the left abdomen. The hard helmet worn by the astronaut is made of polycarbonate, which allows high strength and low weight. The spherical visor can be opened on hinges. Internal air flow and an anti-frosting layer help to keep the visor clear.
Like the Sokol suit, the Chinese space suit is of an open-circuit life-support system. It employs a compressed-gas supply and a demand regulator from which an individual breathes. The exhaust gases along with the cooling and ventilation air is then piped away from inside the suit via a separate hose. Such a design is less complex than a ‘closed-circuit’ system, but a great deal of useable oxygen still present in the exhaled breathing gas is lost in this manner, thus significantly increasing the rate of oxygen consumption. When worn on the ground, the suit is attached to a hand-held portable ventilation unit that supplies air to the suit and removes body heat via a heat exchanger.
The intra-vehicular activity space suit is intended to be worn during the spacecraft launch and re-entry procedures, as well as in an emergency such as depressurisation of the spacecraft cabin. During the first manned mission Shenzhou 5, the astronaut Yang Li-Wei wore the space suit throughout the entire flight. In subsequent missions, the crew would take off their space suits after the spacecraft had entered the orbit, and only wore a blue flight suit during the mission before re-entry. In case of an emergency, the crew would return to the spacecraft’s re-entry module, seal the hatch and put on their space suits within few minutes. The space suit could provide the wearer with life support and temperature regulation for over 6 hours.