Encyclopedia Astronautica
1971.04.23 - Soyuz 10 docking failure.


Soyuz 10 approached to 180 m from Salyut 1 automatically. It was hand docked after faillure of the automatic system, but hard docking could not be achieved because of the angle of approach. Post-flight analysis indicated that the cosmonauts had no instrument to proivde the angle and range rate data necessary for a successful manual docking. Soyuz 10 was connected to the station for 5 hours and 30 minutes. Despite the lack of hard dock, it was said that the crew were unable to enter the station due to a faulty hatch on their own spacecraft. When Shatalov tried to undock from the Salyut, the jammed hatch impeded the docking mechanism, preventing undocking. After several attempts he was unable to undock and land.

Kamanin's account: Docking was planned for 03:00. The Igla system takes over 16 km from the station at 27 m/s closing rate. At 500 m the rate is down to 2 m/s. At 200 m Shatalov takes control of the spacecraft for a manual docking. Contact is made with the stations docking ring at 20-30 cm/s velocity. After 15 minutes, Shatalov reports that he cannot get a docking light - there is no electrical connection between the spacecraft and the station. Telemetry shows that the spacecraft and station are still separated by a 90 mm gap. It is impossible to obtain a hermetic seal of the docking mechanisms. The crew have no spacesuits that would allow them to move to the station through free space. The cosmonauts can't do anything but sit and wait for advice from the ground.

They try repeatedly to force the docking, but nothing works. After four revolutions soft-docked to the station, they are ordered to separate. The cosmonauts had by then tried all of the ground's recommended actions. There was no panic, and all possible variants were attempted.

The Soyuz 10 ECS is left with 40 hours of oxygen - a few metres away in the station, is 3 months' supply. But there are no spacesuits, either in the Soyuz or in the station, no provisions for EVA at all. Any attempt to try to make an entry to the station would leave Mishin with the death of three cosmonauts on his hands. It should be possible to try docking again several times, since 80 kg of propellant is allocated for docking (twice what is normally required) and there needs to be only 45 kg remaining for a guaranteed retrofire. But the limited oxygen aboard the spacecraft means the crew has to prepare for return instead.

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