The Flight of Soyuz-29

 

The Soyuz-29 space capsule, in which East German cosmonaut Sigmund Jähn returned to Earth, is on display at the Bundeswehr Museum of Military History in Dresden.

  The Soyuz capsule. Image:©MHM.

The Soyuz Programme

Originally, it was designed for military purposes. But over the years, it was increasingly used for civilian purposes. More sophisticated versions of the Soyuz spacecraft are still in use today. The Soyuz-29 displayed at the Bundes¬wehr Museum of Military History is a famous spacecraft. In 1978, it safely carried Sigmund Jähn - the first German in space - back to Earth. As part of the Soyuz-7K-T series, the Soyuz-29 belongs to the second generation of Soyuz spacecraft technology. Between 1972 and 1981, thirty Soyuz capsules were sent into space.

Before lift-off, the spacecraft weighed almost 6.8 tons (today: approx. 2 tons) and was composed of three modules: the orbital module, the service module, and the descent module. The more colloquial term that is commonly used for the latter is "space capsule". The three-module Soyuz-29 was launched on 15 June 1978 to carry the two Soviet cosmonauts Vladimir V. Kovalyonok and Aleksandr S. Ivanchenkov to the Salyut-6 space station. The flights to the space station took comparably long. The two cosmonauts had to hold out for more than 24 hours in the capsule, the interior of which measured only 3.8 m³.

On 26 August 1978, Soyuz-31 was launched. On board were military officers Valery F. Bykovsky and Sigmund Jähn, who were to work seven days on the Salyut-6 space station. On 03 September 1978, the descent module of Soyuz-29 was used to bring Bykovsky and Jähn back to earth. Thus, Soyuz-29 had been in space for about 80 days. The maximum usage allowed was 90 days.

Photograph: Soviet cosmonaut Ivanchenkov aboard Salyut-6, photo taken in 1978 by S. Jähn ©Jähn/MHM

Return to Earth

On 03 September 1978 at 11:20 a.m. Moscow time, Soyuz-29 undocked from the Salyut-6 space station. The velocity was 8 kilometres per second (28,800 km/h or roughly 17,500 mph). At 01:51 p.m., the braking engines fired, which would then reduce the speed of the capsule over a period of exactly 215.3 seconds. At that moment, the spacecraft was above the Atlantic Ocean and still about 10,000 km (or roughly 6,200 miles) away from where it was supposed to land.

At 02:04 p.m., the orbital and service modules were jettisoned and subsequently burned up in Earth's atmosphere. Soyuz-29 was just passing Sudan at a height of 120 kilometres (roughly 75 miles). At 02:18 p.m., the critical phase of the descent began at a height of 70 kilometres (43 miles) and a speed of approximately 1.2 kilometres per second (4,320 km/h or 2680 mph).

A heat shield that was turned towards the Earth protected the two cosmonauts from the extreme outside temperatures of about 3,000°C (5430°F) caused by the friction of the capsule against Earth's atmosphere. Exterior elements such as antennae burned up. Inside the capsule, however, the temperature only rose from 20°C (68°F) to 22°C (72°F). Due to the massive deceleration, the two cosmonauts were exposed to fivefold gravity acceleration. At 02:19 p.m., radio communications were interrupted. At 02:23 p.m., radio contact was re-established.

At 02:25 p.m., the main parachute started to unfold at a height of 10 kilometres (6.2 miles), thereby reducing the speed from 864 km/h (537 mph) to 22 km/h (13.7 mph) at a height of 4.5 kilometres (2.8 miles). In the meantime, the heat shield had been jettisoned. At 02:40 p.m., the landing engines fired for a short moment at a height of one metre (3.3 feet) to slow the capsule down to 10 km/h (6.2 mph). What followed only little later was a hard landing, because the parachute had not been detached from the capsule as planned. Sigmund Jähn suffered injuries that caused permanent damage to his spine.

Soyuz-29 – from the flight to the present

The Soviet Union donated the descent module of Soyuz-29 to the East German Armed Forces (National People's Army, German: NVA) for an exhibition in the Army Museum in Dresden (which is today the Bundeswehr Museum of Military History). The East German Army Museum first put Soyuz-29 on display in a very successful special exhibition that started in 1978. The museum staff had to protect the space capsule with a fine-meshed net to prevent souvenir hunters from damaging it. Later on, it was presented in the permanent exhibition, where it can still be seen today. It is located in the area "Technology and the Military" in the Libeskind Wedge.

Author: Jens Wehner, historian and Head of the Department for Photography, Film and Video at the Bundeswehr Museum of Military History in Dresden.