Sokol (spacesuit)

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Sokol spacesuit lying in the bucket seat

The Sokol space suit ( Russian Сокол for falcon ) is a Russian space suit that is worn by all cosmonauts on board the Soyuz spacecraft during take-off, landing and docking maneuvers. This type was first used in 1973 and is still used. It is called a rescue suit by the manufacturer NPP Zvezda , as it is only used to protect the spaceman in the event of a loss of pressure on board the Soyuz spaceships. This means that it has the same function as the well-known orange US American ACE suit that was worn by the space shuttle astronauts when the space shuttle took off and landed. With the Sokol suit, no external action is possible. B. the Russian Orlan-D space suits.

description

Yuri Ussachev in his Sokol-KV2

The current version of the suit is called Sokol-KW2 (Сокол КВ-2). It consists of an inner pressure sleeve made of Kapron and an outer sleeve made of white nylon . The shoes are integrated into the suit, while the gloves are removable and attached using a coupling made of blue anodized aluminum . The polycarbonate - visor is mounted on hinges at ear level and closes in the closed condition with an anodized aluminum flange of the suit from. The cap or inner soft helmet folds up when the visor is opened. The spacesuit has four pockets on the legs and adjustment straps on the arms, legs, chest and stomach.

The pressure gauge for internal pressure is located on the left wrist. A mirror is worn on the right joint on an elastic band. This enables the cosmonaut to read instruments that are normally out of his field of view. An altimeter is also worn during re-entry to check cabin pressure. Often a wrist watch is attached to the space suit with an elastic band. Most of the watches are of Swiss or Russian origin and bought privately.

Electrical and communication connections are on the right at stomach height. The separate connections for air and oxygen are located on the left. In the normal state, an electrically driven fan blows air from the cabin through the suit at a rate of 150 l / min. If the cabin pressure falls below 600 hPa , the air supply is automatically replaced by oxygen from pressure bottles. The suit maintains this internal pressure no matter how deep the cabin pressure drops. Air and oxygen leave the suit through the blue pressure relief valve in the center of the chest. The space suit is thus an open life support system, similar to a diving suit . This makes the suit very easy to assemble. The disadvantage is the high oxygen consumption, which is justifiable since the system is only needed in an emergency.

The suits weigh about ten kilograms and are perceived by some wearers as a considerable hindrance to movement. They are designed to be worn for up to 30 hours in a normal pressure environment and up to two hours in a vacuum . In addition, the suits are buoyant and have a neck collar that prevents water from entering the suit. The Soyuz crews are equipped with buoyancy aids and cold weather survival equipment for an emergency ditching.

By the end of 2002, 309 airworthy and 135 test or training suits had been produced. These numbers have now increased even further due to the use of the Soyuz spaceships as ISS feeders.

application

Each cosmonaut is equipped with a handcrafted suit for space flight. It is very important that the suit fits perfectly. To check this, the future space travelers sit for two hours with their Sokol suit on in their tailor-made Kazbek-U-shell seat (Russian Казбек-У ) and the suit is precisely adjusted with the straps on the arms, legs and chest and changed if necessary . So strict attention is paid to the exact fit of the suit in order to avoid injuries and pressure points during take-off and landing, where loads of several G occur. The exact adjustment of the seat and suit makes it necessary that the bucket seats have to be transferred from one Soyuz spaceship to another in the event that the cosmonaut comes back with a spacecraft other than the launch vehicle.

Crew of Soyuz TMA-9 in their Sokol spacesuits with portable ventilation devices

To get into the space suit, the two V-shaped zippers on the front are opened. Underneath there is a large hose-shaped opening in the pressure envelope, which is called the appendix. The cosmonaut starts with his feet first, then guides his arms through the openings provided and at the end sticks his head into the helmet from below. For sealing, the appendix is ​​then rolled up tightly (similar to waterproof bicycle bags with roll closure ) and fixed with elastic straps. The bead of the rolled up appendix is ​​tucked under the V-shaped flap on the front. Worn on the floor, the space suit is connected to a portable ventilation device, which ensures ventilation and cooling of the suit. To avoid damage to the feet of the suit, gray leather shoes are pulled over the suit on the floor. These must be removed before entering the Soyuz spaceship. This also prevents contamination of the pressurized cabin.

The Sokol pressure suit is worn for take-off and landing, with the gloves pulled on and the visor closed. During an emergency, the suit maintains an internal pressure of usually 400 hPa above ambient pressure. The suit will inflate a little and restrict the cosmonaut's freedom of movement. It should still be possible to operate the spaceship.

If the impairment of mobility becomes too great, it is possible to set the blue pressure relief valve to a lower pressure of 270 hPa (backup mode). Then the suit is supplied with pure oxygen. Because of the risk of decompression sickness , this is only intended for absolute emergencies.

history

Pressure suits were already worn on the Vostok flights. When the new Soyuz spaceship was designed in the mid-1960s, the developers in the OKB -1 design office made the controversial decision not to use them in the new spaceships. Some of the early Soyuz missions had Jastreb -Raumanzüge on board, but only for extravehicular activities were used.

On June 30, 1971, the Soyuz 11 crew died on re-entry when the air escaped from their landing capsule due to a defective air valve . One of the recommendations of the commission of inquiry was that all future crews must wear pressure suits during critical phases (take-off, landing, coupling maneuvers) of their mission.

NPP Zvezda was given the task of developing new suits for Soyuz. They refused to take over existing spacesuits because they were either developed for longer use in a vacuum and / or were unsuitable for use with the Kazbek shell seats of the Soyuz spaceships. The designers under the direction of Gai Ilyich Sewerin developed a new model based on the Sokol pressure suit for fighter pilots. The main difference between the new suit was a different helmet. Only equipment details required for aviation were left out, which helped to save weight.

At the same time, the life support system was developed in cooperation with Sergei Korolev's development office . The finished suit was named Sokol-K , where K stands for cosmos .

variants

Sokol-K

The original version of the Sokol suit was first used on the Soyuz 12 flight in 1973. In contrast to the current model, the pressure cover is made of rubber and the outer cover is not closed with the V-shaped zipper, but rather laced. The wearer of the suit had to wear the communication hood and a belt with biosensors under this cotton undergarment.

Sokol-KR

The Sokol-KR version (Russian Сокол КР , "R" for regenerative) was developed for use with the TKS spaceship , which was part of the military Almaz program. The suit was never used as the TKS spaceships only flew unmanned. The main difference is that this suit is designed to work with a regenerative life support system.

Sokol-KM and Sokol-KW

Work to improve Sokol-K began in 1973. The Sokol-KM (Russian Сокол КМ , “M” модификация for modified ) and KW (Russian Сокол КВ , “W” for ventilated ) were intermediate models for the development of the Sokol-KW2 and were not used on any flight into space.

Sokol-KM and KW consisted of an upper and a lower half, which were connected with zippers. This principle was abandoned for the further developed Sokol-KW2 and access through the appendix was reintroduced. The developers decided that this would make the suit more reliable than the airtight zippers that were available. Additional changes concerned the outer fabric on the joints and the gloves to make the spaceship easier to use.

To increase comfort, both types were equipped with a water-cooled undergarment. This allowed the excess body heat to be dissipated more efficiently. All other suits use air for this.

Sokol-KW2

Sokol-KW2, the current version, was used for the first time on the Soyuz T-2 flight on June 5, 1980.

The main improvement over Sokol-K was the replacement of the rubber inner pressure sleeve with one made of rubberized kapron, a polyamide. This made it possible to reduce the weight of the suit. The visor has been improved and enlarged to improve the cosmonaut's field of vision . Straps on the outer shell have been replaced with zippers to make it easier to put on and take off. The pressure relief valve moved from the left side of the abdomen to the center of the chest to enable it to be operated with both hands. The improvements to arms, legs and gloves from Sokol-KW were also adopted, even if the water-cooled underwear from KM and KW was not adopted. The price for such a suit is said to be 30,000 euros.

Developments in other countries

Chinese spacesuit by Yang Liwei

It is known that China bought a number of spacesuits from Russia for its space program . Yang Liwei's suit , which he wore during the first Chinese manned space flight with Shenzhou 5 , looks like a Sokol-KW2, but it is believed to be more of a Chinese replica. Pictures of the Taikonauts Fei Junlong and Nie Haisheng from Shenzhou 6 show slightly different suits. It is also reported that these are easier.

Sokol suits were also bought for other uses. It was planned that the crew of the British high altitude balloon QinetiQ 1 would wear modified suits from NPP Zvezda. Since the balloonists were supposed to sit in an open platform during the flight, the Sokol suits, together with thick, warm outer clothing, would have protected them from the cold and the low pressure in the stratosphere . The balloon should rise to a height of 40 km. The project was abandoned after damage to the balloon.

Collectors market

Sokol suits, including those used by cosmonauts in space, were first offered by Sotheby’s at an auction in 1993 with other items related to Russian space history. After that, items of equipment such as gloves, communication hoods and hand mirrors, and occasionally even complete suits , appeared on the eBay Internet auction platform. Usually this is discarded worn out training equipment that has never been in space. These things actually belong to Russia, so the legality of the sale is doubtful. It is also believed that the Russian mafia is involved in the trade.

Technical specifications

As of December 31, 2002

Characteristics Sokol-K Sokol-KW Sokol-KW2
Development period 1971-1973 1974-1979 1973-1979
Period of use 1973-1981 - 1980 until now
Working time in a ventilated cabin up to 30 h
Working time in a pressureless cabin up to 2 h
Nominal pressure standard mode 400 hPa
Nominal pressure backup mode 270 hPa
Air flow ≥ 150 slpm
Oxygen flow 20 slpm
Weight 10 kg 12 kg 9 kg
Manufactured specimens:
Airworthy / test and training 		89/66 0/6 220/63

Web links

Commons : Sokol  - collection of pictures, videos and audio files

swell

  1. ↑ Description of the Sokol suit (English)
  2. ↑ a b c d Isaak P. Abramow, A. Ingemar Skoog: Russian Space Suits . Springer Practice, 2003, ISBN 1-85233-732-X .
  3. ↑ a b c Helen Sharman , Cristopher Priest: Seize the Moment . Gollancz, 1993, ISBN 0-575-05628-2 .
  4. ↑ a b Sotheby’s Catalog - Russian Space History , Item 6516, December 11, 1993
  5. ↑ image of the appendix
  6. ↑ Christopher S. Stuart: Psst - Wanna Buy a Slightly Used Soviet Space Suit . Wired Magazine, April 2005 issue
This version was added to the list of articles worth reading on July 23, 2006 .