Zond (
Russian: Зонд,
lit. 'probe') was the name given to two distinct series of
Sovietrobotic spacecraft launched between 1964 and 1970. The first series, based on the
3MV planetary probe, was intended to gather information about nearby planets.
The second series of test spacecraft was intended as a precursor to remote-controlled robotic circumlunar loop flights, using a stripped-down variant of
Soyuz spacecraft, consisting of the
service and
descent modules, but lacking the
orbital module.
Two tortoises and other lifeforms aboard
Zond 5 were the first terrestrial organisms to travel around the Moon and return to Earth.
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 (after
Luna 3). It then continued out to the orbit of Mars in order to test telemetry and spacecraft systems.
The missions
Zond 4 through
Zond 8 were test flights 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 kind of path flown by
Apollo 13 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 to 1970 (
Zond 4 to
Zond 8) showed problems during re-entry.
The Zond spacecraft made only uncrewed 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.
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 (6.2 to 9.3 mi) altitude, 180–200 km (110–120 mi) off the African coast at Guinea.
A 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.
Uncrewed missions are designated as Kosmos instead of Soyuz; exceptions are noted "(uncrewed)".
The † sign designates failed missions. Italics designates cancelled missions.