Zond (Зонд; Russian for "probe") was the name given to two distinct series of Soviet unmanned space program undertaken from 1964 to 1970. The first series based on 3MV planetary probe was intended to gather information about nearby planets. The second series of test spacecraft being a precursor to manned circumlunar loop flights used a stripped-down variant of Soyuz spacecraft, consisting of the service and descent modules, but lacking the orbital module.
The first three missions were based on the model 3MV planetary probe, intended to explore Venus and Mars. After two failures, Zond 3 was sent on a test mission, becoming the second spacecraft to photograph the far side of the Moon. It then continued out to the orbit of Mars in order to test telemetry and spacecraft systems.
The missions 4 through 8 were test flights under for the Soviet Moonshot during the Moon race. The Soyuz 7K-L1 (also mentioned just as L1) spacecraft was used for the Moon-aimed missions, stripped down to make it possible to launch around the Moon from the Earth. They were launched on the Proton rocket which was just powerful enough to send the Zond on a free return trajectory around the Moon without going into lunar orbit (the type path that Apollo 13 flew in its emergency abort). With minor modification, Zond was capable of carrying two cosmonauts.
In the beginning there were serious reliability problems with both the new Proton rocket and the similarly new Soyuz spacecraft, but the test flights pressed ahead with some glitches. The majority of test flights from 1967–1970 (Zond 4 to Zond 8) showed problems during re-entry.
The Zond spacecraft made only unmanned automatic flights. Four of these suffered malfunctions that would have injured or killed any crew. Instrumentation flown on these missions gathered data on micrometeor flux, solar and cosmic rays, magnetic fields, radio emissions, and solar wind. Many photographs were taken and biological payloads were also flown.
Zond 1Launched 2 April 1964Communications lost 14 May 1964Venus flyby 14 July 1964Zond 2Launched 30 November 1964Communications lost May 1965Mars flyby 6 August 1965Zond 3Launched 18 July 1965Lunar Flyby 20 July 1965Cosmos 146Launched 10 March 1967Prototype Soyuz 7K-L1P launched by Proton into planned highly elliptical earth orbit.Cosmos 154Launched 8 April 1967Prototype Soyuz 7K-L1P launched by Proton and failed to go into planned translunar trajectory.Zond 1967ALaunched 28 September 1967Fell off course 60 seconds after launch. Escape tower took Zond capsule safely away. Rocket crashed 65 km downrange.Attempted Lunar flybyZond 1967BLaunched 22 November 1967Second stage failure. Zond capsule was safely recovered. Rocket crashed 300 km downrange.Attempted Lunar flybyZond 4Launched 2 March 1968Study of remote regions of circumterrestrial space, development of new on-board systems and units of space stations.Returned to Earth 7 March 1968—Self destruct system automatically blew up the capsule at 10 to 15 km altitude, 180–200 km off the African coast at Guinea.Zond 1968ALaunched 23 April 1968Second stage failed 260 seconds after launch.Attempted Lunar flybyZond 1968B (Zond 7K-L1 s/n 8L)Launched 21 July 1968Block D stage exploded on pad, killing three people.Zond 5Launched 15 September 1968Circumlunar 18 September 1968Returned to Earth 21 September 1968A biological payload of two Russian tortoises, wine flies, meal worms, plants, seeds, bacteria, and other living matter was included in the flight, and were the first Earth lifeforms to travel around the moon and return safely.The first spacecraft to circle the Moon and return to land on Earth.Zond 6Launched 10 November 1968Circumlunar 14 November 1968Returned to Earth 17 November 1968Zond 1969ALaunched 20 January 1969Stage two shutdown 25 seconds early. Automatic flight abort. Capsule was safely recovered.Attempted Lunar flybyZond L1S-1Launched 21 February 1969First stage failure. Capsule escape system fired 70 seconds after launch. Capsule was recovered.Attempted Lunar orbiter and N1 rocket testZond L1S-2Launched 3 July 1969First stage failure. Zond capsule was recovered.Attempted Lunar orbiter and N1 rocket testZond 7Launched 7 August 1969Lunar flyby 11 August 1969Returned to Earth 14 August 1969Zond 8Launched 20 October 1970Lunar flyby 24 October 1970Returned to Earth 27 October 1970Zond 9Planned but cancelledZond 10Planned but cancelled
