The Forel immersion suit is a protective garment that can keep a cosmonaut afloat in water and protect them from exposure to cold, wind, rain or snow on land. It is used when the descent module (DM) of the spacecraft makes an emergency landing in an unfamiliar location, which may be either on water or an inaccessible and uninhabited area on land.

This suit is a single garment — the only part that can be detached from the suit is the gloves. The wearer’s head is protected from water and cold by a rubber helmet. On the shoulders there is a buoyant collar, which inflates when the suit is immersed in water and serves as a life ring. The suit is designed to be worn under several layers of warm clothes, in order to preserve heat.

The Forel suit can keep a cosmonaut alive for at least 12 hours in water with a temperature of –1⁰С or when the air temperature is –10⁰С. At higher temperatures, it can keep the wearer alive for several days. The suit is bright orange in color, in order to assist search parties. When it is dark, the light emitting diode device on the front of the suit lights up.

During the launch and reentry of a spacecraft it is impossible to exclude the risk of accidents which threaten the life of the crew. The emergency may occur while the craft is over water, or the DM may land on water (as happened on October 16, 1976, when cosmonauts Viacheslav Zudov and Valery Rozhdestvensky landed on Lake Tengiz, in Kazakhstan. Moreover, once the test flights from the Vostochny rocket launch site begin, it is possible that the DMs from spacecraft may make emergency landings on the Pacific Ocean rather than on dry land.

Before take-off the cosmonauts undergo extensive training in the use of the immersion suit. A “long” training session may last an hour and a half. During that time the cosmonaut must take off the Sokol space helmet, put on more layers of warm clothes (the flight costume, a woolen pullover, and thermal clothes) and then the Forel immersion suit, and, wearing all those clothes, must get out of the descent module, taking with them the necessary emergency supplies.

The whole operation needs to be carried out in the cramped conditions of the descent module (which has a diameter of 2.2 meters and a total volume of about 2.5 cubic meters), while the module is being tossed by the waves. During their training the body temperature of the cosmonauts increases to 40⁰С, their pulse reaches 150-170 beats per minute, their blood pressure increases and they experience oxygen deprivation because of the poor ventilation. As a result of such demanding training, a cosmonaut can lose up to 5 kg.

When in the water, the members of the crew lie on their backs, fasten their legs to each other to form a star shape, and start to scull towards the shore. They set off a signal flare. The Forel immersion suit provides the cosmonaut with the buoyancy they need to stay afloat, and keeps them safe while they wait for the rescuers to arrive.