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Zond program
Zond ("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, photographing the far
side of the Moon (only the second spacecraft to do so) and
continuing 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 same
path that Apollo 13 flew in its emergency abort). With minor
modification, Zond was capable of carrying 2 cosmonauts.
In the beginning there were serious reliability
problems with both the new Proton rocket and the similar new Soyuz
spacecraft, but the test flights pressed ahead with some glitches.
Then majority of tests flights from 1967-1970 (Zond 4 to Zond 8)
showed problems during re-entry.
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.
3MV planetary probe based missions
Zond 1
Launched 2 April 1964
Communications lost 14 May 1964
Venus flyby 14 July 1964
Zond 2
Launched 30 November 1964
Communications lost May 1965
Mars flyby 6 August 1965
Zond 3
Launched 18 July 1965
Lunar Flyby 20 July 1965
Soyuz 7K-L1 test missions
Cosmos 146
Launched 10 March 1967
Prototype Soyuz 7K-L1P launched by Proton into planned highly
elliptical earth orbit.
Cosmos 154
Launched 8 April 1967
Prototype Soyuz 7K-L1P launched by Proton and failed into planned
translunar trajectory.
Zond 1967A
Launched 28 September 1967
Fell off course 60 seconds after launched. Escape tower took Zond
capsule safely away. Rocket crashed 65 km downrange.
Attempted Lunar flyby
Zond 1967B
Launched 22 November 1967
Second stage failure. Zond capsule was safely recovered. Rocket
crashed 300 km downrange.
Attempted Lunar flyby
Zond 4
Launched 2 March 1968
Study 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 1968A
Launched 23 April 1968
Second stage failed 260 seconds after launch.
Attempted Lunar flyby
Zond 1968B (Zond 7K-L1 s/n 8L)
Launched 21 July 1968
Block D stage exploded on pad, killing three people.
Zond 5
Launched 15 September 1968
Circumlunar 18 September 1968
Returned to Earth 21 September 1968
Turtles and other biological specimens were the first lifeforms to
travel to lunar orbit and return safely.
Zond 6
Launched 10 November 1968
Circumlunar 14 November 1968
Returned to Earth 17 November 1968
Zond 1969A
Launched 20 January 1969
Stage two shutdown 25 seconds early. Automatic flight abort.
Capsule was safely recovered.
Attempted Lunar flyby
Zond L1S-1
Launched 21 February 1969
First stage failure. Capsule escape system fired 70 seconds after
launch. Capsule was recovered.
Attempted Lunar orbiter and N1 rocket test
Zond L1S-2
Launched 3 July 1969
First stage failure. Zond capsule was recovered.
Attempted Lunar orbiter and N1 rocket test
Zond 7
Launched 7 August 1969
Lunar flyby 11 August 1969
Returned to Earth 14 August 1969
Zond 8
Launched 20 October 1970
Lunar flyby 24 October 1970
Returned to Earth 27 October 1970
Zond 9
Planned but cancelled
Zond 10
Planned but cancelled
Zond 5
Zond 5, a formal member of the Soviet Zond
program and unmanned version of Soyuz 7K-L1 manned moon-flyby
spacecraft, was launched from a Tyazheliy Sputnik (68-076B) in
Earth parking orbit to make scientific studies during a lunar flyby
and to return to Earth.
Zond-5 became the first spacecraft to circle the
Moon and return to land on Earth. On September 18, 1968, the
spacecraft flew around the Moon. The closest distance was 1,950 km.
High quality photographs of the Earth were taken at a distance of
90,000 km. A biological payload of two russian tortoises, wine
flies, meal worms, plants, seeds, bacteria, and other living matter
was included in the flight.
September 21, 1968, the reentry capsule entered
the Earth´s atmosphere, braked aerodynamically by means of skip
reentry, and deployed its parachutes at 7 km. The capsule splashed
down in the Indian Ocean and was successfully recovered by the USSR
recovery vessels Borovichy & Vasiliy Golovin. The biological
payload was intact, proving that it was possible to survive a lunar
flyby and safely return to Earth. It was announced that the turtles
had lost about 10% of their body weight but remained active and
showed no loss of appetite. The spacecraft was planned as a
precursor to manned lunar spacecraft.
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