Launch Date Nov. 30, 1964
Launch Site Baikonur Cosmodrome, Kazakhstan, Russia | Launch Site 1
Destination Mars
Type Flyby
Status Partial Success
Nation Soviet Union
Alternate Names 3MV-4 No.2, 1964-078C, 00945


This Soviet third-generation spacecraft was designed to fly by Mars and take photographs. It also carried equipment to study interplanetary space.


A solar panel malfunction deprived the spacecraft of critical power and communications were lost before it reached Mars. However, mission controllers were able to twice test fire plasma electric ion rocket engines -- making Zond 2 a successful technology test for future deep space missions.

Key Dates

Nov. 30, 1964: Launch
Dec. 18, 1964: Engine Technology Test
Aug. 6, 1965: Planned Mars Flyby (Unsuccessful)

In Depth

Zond 2 was the Soviet Union's first third-generation ("3MV") spacecraft sent toward Mars. This particular model, the 3MV- 4, was designed to fly by the planet and take photographs.

After the spacecraft successfully entered a trans-Mars trajectory, ground controllers discovered that the probe's solar panels had not completely unfurled, which deprived the vehicle of full power. Later investigation indicated that a tug cord, designed to pull the panels free at the moment of separation from the Blok L upper stage, had broken off.

Controllers were able to fully open the panel only on 15 December 1964, but by then the time for the first midcourse correction to fly by Mars had already passed. Additionally, between communications sessions, there had been a failure in the onboard programmed timer immediately after transinterplanetary injection that led to inappropriate thermal conditions for the spacecraft.

On 18 December 1964, before loss of contact, Zond 2 successfully fired six plasma electric rocket engines (twice) as a technology demonstrator for future deep space missions.

The spacecraft was to have flown by Mars on 6 August 1965. It eventually entered heliocentric orbit.


Launch Vehicle: Modified SS-6 (Sapwood) 8K78

Spacecraft Mass: 996 kg

Spacecraft Instruments:

  1. radiation detector
  2. charged-particle detector
  3. magnetometer
  4. piezoelectric detector
  5. radio telescope
  6. nuclear component of cosmic-ray experiment
  7. ultraviolet and Roentgen solar radiation experiment
  8. imaging system

Spacecraft Power: Two solar panels

Additional Resources

NSSDC Master Catalog: Zond 2

Selected References

Siddiqi, Asif A. Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, NASA, 2002.

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