Zond 6

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Zond 6
Organization Soviet Union
Major contractors NPO Energia Company
Mission type Planetary Science
Launch November 10, 1968 at 19:11:00 [GMT]
Launch vehicle Proton 8K82K / 11S824
Mission highlight Fly-by of Moon on November 14, 1968 at distance of 2,420km
Mission duration 5.79 days
Mass 5375 kg
Webpage [1]
Orbital elements
Satellite of Moon
Inclination 51.5°
Orbital period 500 d
Apoastron 400,000 km
Periastron 120 km
Instruments
cosmic ray and micrometeoroid detectors, photography equipment, and a biological payload

Zond 6, a member of the Soviet Union's Zond program, was launched on a lunar flyby mission from a parent satellite (68-101B) in Earth parking orbit. The spacecraft, which carried scientific probes including cosmic ray and micrometeoroid detectors, photography equipment, and a biological payload, was a precursor to a manned circumlunar flight which the Soviets hoped could occur in December of 1968, beating the American Apollo 8.

Zond 6 flew around the moon on November 14, 1968, at a minimum distance of 2420 km. Photographs of the lunar near side and far side were obtained with panchromatic film. Each photo was 5 in by 7 in (127.0 by 177.8 mm). Some of the views allowed for stereo pictures. The photos were taken from distances of approximately 11,000 km and 3300 km. Skipped reentry of the spacecraft did not occur, Zond 6 landed in an undetermined region of the Soviet Union.

Zond 6 used a relatively uncommon technique called "skip reentry", defection, to shed velocity upon returning to Earth. A few hours before reentry, a faulty O-ring rubber gasket caused the cabin to depressurise, killing all biologicals aboard. Zond 6's parachutes also deployed too early and it crashed on Soviet soil. Only one negative was recovered from the camera container and a small victory obtained over the Americans. For propaganda reasons, the Soviets claimed the flight was a success, but they were not able to launch a manned flight to the Moon before Apollo 8. A State Commission investigating the crash later determined that the coronal discharge effect which caused the parachute to jettison would only occur at the 25 mm capsule pressure. If the capsule had been completely depressurised to a high vacuum, the accident would not have occurred.

Zond 6 was the cover name for Soyuz 7K-L1 s/n 12. It was supposed to photograph the moon in colour and black and white from 8000 km and 2600 km ranges, then return to earth, landing at Tyuratam only 16 km from the launch pad. It had been a long and difficult road to develop the L1 guidance system, but it worked perfectly that time.

  • Launch Date/Time: 1968-11-10 at 19:11:31 UTC
  • On-orbit dry mass: 5375 kg


Preceded by
Zond 5
Zond program Succeeded by
Zond 1969A

This article was originally based on material from NASA (NSSDC) information on Zond 6 [2]