Mission Type: Flyby
Launch Vehicle: Modified SS-6 (Sapwood) 8K78
Launch Site: Tyuratam (Baikonur Cosmodrome), U.S.S.R., launch site 1
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 and 8) imaging system
Spacecraft Power: Two solar panels
References:
Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, by Asif A. Siddiqi

National Space Science Data Center, http://nssdc.gsfc.nasa.gov/

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.