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GKZh-2: Life's first space-return vehicle

A pill-shaped container accommodating two dogs and a multitude of biological objects flew aboard early prototypes of the Vostok spacecraft in preparation for the first human mission into orbit. The cabin, known as GKZh-2 for Germitecheskaya Kabina Zhivotnogo, which translates to "pressurized animal cabin." was a mini-spacecraft in its own right, becoming the first vehicle designed to return live animals back to Earth after an orbital flight.

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The Vostok ejection seat fitted with the Pressurized Animal Cabin, GKZh-2. This particular vehicle was apparently used during the second launch attempt in August 1960.


The GKZh-2 container (also known as KZh-02) was designed primarily for testing the pilot ejection system of the Vostok spacecraft during automated orbital test flights. The container was fitted into a modified rocket-propelled pilot seat, which was to be ejected from the Descent Module during all nominal landings of the Vostok spacecraft. In case of emergency on the launch pad or during the initial phase of the ascent to orbit, a pilot could also bail out from the spacecraft and parachute to safety.

The development of the GKZh-2 started in 1958 at an aviation industry plant in Lytkarino, outside Moscow, which specialized in life-support and rescue equipment for aircraft. The same organization previously supplied similar gear for launching dogs on research rockets. The work on the GKZh-2 container was based on the experience with the original spacecraft animal cabin, GKZh, which was under development from 1956 to 1957 and paved the way for the one-way launch of the second Soviet satellite with a dog onboard.

According to its official specifications, the GKZh-2 cabin could support two dogs during an orbital flight lasting up to 15 days and for five days on the ground during potential search operations.

The cabin contained a special automated machine for feeding the animals, a waste disposal system, monitoring equipment and additional compartments for other biological objects, such as plants, flies and seeds.

The cylindrical cabin was manufactured out of an aluminum alloy and had two windows for real-time monitoring of the animals during the flight with the help of TV cameras. Depending on the color of the dog, the interior of the cabin could be painted either in dark or light colors to provide a contrast background. (923)

The cabin also had an air-ventilation system and an oxygen supply system, which would be activated after the prototype of the pilot seat had been ejected from the Descent Module. The system would be powered by autonomous batteries also installed in the cabin.

Finally, the GKZh-2 container had a pair of radio transmitters which could be used to maintain communications with mission control after ejection from the main spacecraft. In orbit, scientific data from the cabin would be routed via regular communications channels of the Vostok spacecraft.

The prototype of the cosmonaut seat, which carried the cabin, also had a special antenna helping recovery specialists during the search of the vehicle in the landing area.

After the touchdown, the dogs would be automatically unbuckled from their seats, allowing the animals to get into comfortable positions in the cabin.


Front view of the GKZh container.


To be continued

Page author: Anatoly Zak; Last update: August 20, 2020

Page editor: Alain Chabot; Last edit: August 20, 2020

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A schematic by Oleg Gazenko illustrates the placement of sensors on dogs inside the Vostok spacecraft. Click to enlarge. Credit: IMBP


Belka and Strelka inside GKZh-2 container.


Descent module of the Vostok 1K spacecraft with a GKZh-2 container inside and with its main hatch open.


Frame from a footage likely showing lifting of the GKZh-2 container aboard the Vostok spacecraft.



Post-landing processing of the GKZh-2 container.









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