|Launch Date||Nov. 10, 1968|
|Launch Site||Baikonur Cosmodrome, Kazakhstan, Russia | Launch Site 1|
|Alternate Names||1968-101A, 03535|
Fly around the Moon and return to Earth, taking photographs and testing the effect of space travel on a biological payload.
Zond was the second Soviet spacecraft to fly to the Moon and back. It took pictures of the lunar near and far sides, but crashed on re-entry. Though the picture film was salvaged, the biological payload was lost.
Nov. 10, 1968: Launch
Nov. 14, 1968: Lunar Flyby
Nov. 17, 1968: Return to Earth
Zond 6 was the second spacecraft that the Soviets sent around the Moon.
Soon after translunar injection, ground controllers discovered that the vehicle's high-gain antenna had failed to deploy. Given that the main attitude- control sensor was installed on the antenna boom, controllers had to make plans to use a backup sensor for further attitude control.
The spacecraft circled the far side of the Moon at a range of 2,420 kilometers, once again taking black-and-white photographs of the Moon.
During the return flight, temperatures in a hydrogen peroxide tank for the attitude-control thrusters dropped far below acceptable levels. Engineers attempted to heat the tank by direct sunlight, but as they later discovered, such a procedure affected the weak pressurization seal of the main hatch and led to slow decompression of the main capsule.
Despite the failures, Zond 6 successfully carried a fully automated guided reentry into the primary landing zone in Kazakhstan.
A radio altimeter, not designed for work in depressurized spacecraft, issued an incorrect command to jettison the main parachutes. As a result, the spacecraft plummeted to the ground and was destroyed. Although the main biological payload was lost, rescuers salvaged film from the cameras.
Launch Vehicle: 8K82K + Blok D (Proton-K no. 235-01 / Blok D no. 19)
Spacecraft Mass: about 5,375 kg
- biological payload
- radiation detectors
- imaging system
- photo-emulsion camera
- micrometeoroid detector
Siddiqi, Asif A. Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, NASA, 2002.