Vostok-2M

The Vostok-2M (Russian: Восток meaning "East"), GRAU index 8A92M was an expendable carrier rocket used by the Soviet Union between 1964 and 1991. Ninety-three were launched, of which one failed. Another was destroyed before launch.^[1] It was originally built as a specialised version of the earlier Vostok-2, for injecting lighter payloads into higher sun-synchronous orbits. It was a member of the R-7 family of rockets, and the last Vostok.

The Vostok-2M made its maiden flight on 28 August 1964, from Site 31/6 at the Baikonur Cosmodrome, successfully placing Kosmos 44, a Meteor weather satellite into orbit. Its only launch failure occurred on 1 February 1969, when the launch of a Meteor failed due to an upper stage problem.

At 16:01 GMT on 18 March 1980, a Vostok-2M exploded during fueling Plesetsk Site 43/4, ahead of the launch of a Tselina-D satellite, killing 48 people who were working on the rocket at the time. A filter in a hydrogen peroxide tank of the third stage had accidentally been soldered with tin-lead, the latter of which causes decomposition of hydrogen peroxide.^[2] As a consequence, the H2O2 broke down, overheated, and melted the solder, causing pieces to fall into the H2O2 storage tank and cause a runaway chemical reaction. This led to a fire inside the third stage and eventual explosion which resulted in the complete destruction of the launch vehicle and severe pad damage (LC-43 did not host another launch for three years).

Vostok-2M launches occurred from Site 31/6 at Baikonur, and Sites 41/1 and 43 at Plesetsk. It is unclear if any were launched from Site 1/5 at Baikonur. The Vostok-2M was retired in 1991, in favour of standardisation on the Soyuz-U and U2 rockets. The final flight was conducted on 29 August, and carried the IRS-1B satellite for the Indian Space Research Organisation.

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