Zond 6 was a formal member of the Soviet Zond program, and an unmanned version of the Soyuz 7K-L1 manned Moon-flyby spacecraft. It was launched on a lunar flyby mission from a parent satellite (68-101B) in Earth parking orbit. The spacecraft carried scientific probes including cosmic ray and micrometeoroid detectors, as well as photographic equipment and a biological payload of flies, bacteria and turtles. The mission was a precursor to a manned circumlunar flight which the Soviets hoped could occur in December 1968, thus beating the American Apollo 8. However, after rounding the Moon, Zond 6 crashed on its return to Earth, due to a parachute failure.
![]() | This article needs additional citations for verification. (March 2014) |
![]() | |||||||||
Names | Soyuz 7K-L1 s/n 12 | ||||||||
---|---|---|---|---|---|---|---|---|---|
Mission type | Planetary Science | ||||||||
Operator | Lavochkin | ||||||||
COSPAR ID | 1968-101A ![]() | ||||||||
SATCAT no. | 03535 | ||||||||
Mission duration | 7 days | ||||||||
Spacecraft properties | |||||||||
Manufacturer | NPO Energia Company [citation needed] | ||||||||
Launch mass | 5,375 kg (11,850 lb) | ||||||||
Start of mission | |||||||||
Launch date | 19:11:31, 10 November 1968 (UTC) (1968-11-10T19:11:31Z) | ||||||||
Rocket | Proton-K/11S824 | ||||||||
Launch site | Baikonur 81/26 | ||||||||
End of mission | |||||||||
Disposal | Crash landed | ||||||||
Landing date | 17 November 1968 (1968-11-17) 14:10 UT[1] | ||||||||
Landing site | 70 km NE of Tyuratam, Kazakhstan, USSR[2] | ||||||||
Orbital parameters | |||||||||
Perigee altitude | 120 km (75 mi) | ||||||||
Apogee altitude | 400,000 km (250,000 mi) | ||||||||
Inclination | 51.5° | ||||||||
Period | 500 days | ||||||||
Flyby of Moon | |||||||||
Closest approach | 14 November 1968 | ||||||||
Distance | 2,420 km (1,500 mi) | ||||||||
| |||||||||
Zond Zond 1969A → |
Zond 6 was the official designation for Soyuz 7K-L1 s/n 12. It was supposed to photograph the Moon in colour and in black and white, from 8,000 km and 2,600 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.
Zond 6 flew around the Moon on 14 November 1968, at a minimum distance of 2,420 km. Photographs of the lunar near side and far side were obtained with panchromatic film. Each photo was 5 by 7 in (130 by 180 mm). Some of the views allowed for stereo pictures. The photos were taken from distances of approximately 11,000 km and 3,300 km.
The flight was tracked by Jodrell Bank Observatory, which picked up telemetry data and voice transmissions. The telemetry data appear to have been simulated sensor readings; the voices were either from a tape recorder or being relayed through the probe.[3] In 2018, a recording of the signals was found in Jodrell Bank's archive.[3]
During the craft's return from the moon, concerns arose about the falling temperatures of the hydrogen peroxide tanks.[4] This issue was addressed by rotating Zond 6 so that the tanks were in direct sunlight.[4] While this was successful in raising the temperatures of the tanks, it also damaged the seal around the door of the re-entry cabin, resulting in the spacecraft starting to leak and the pressure in the cabin falling.[4]
Zond 6 used a relatively uncommon technique called "skip reentry" to shed velocity upon returning to Earth. A few hours before reentry, on 17 November 1968, the cabin largely depressurised, killing all the animal test subjects aboard. A further problem resulted in Zond 6's parachutes ejecting while the cabin was still several miles up. The craft crashed in Kazakhstan, near the designated landing area.[5]
Investigation of the remains of the spacecraft was delayed while the self destruct system was located and removed.[4] The craft's film magazines could then be recovered, and the images therein were published, along with claims that the mission had been entirely successful.[4][5]
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.
This article was originally based on material from NASA (NSSDC) information on Zond 6
Zond program | ||
---|---|---|
3MV based missions | ![]() | |
Soyuz 7K-L1/L1S |
| |
Other |
Spacecraft missions to the Moon | |||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Exploration programs |
| ||||||||||||||||
Active missions |
| ||||||||||||||||
Past missions |
| ||||||||||||||||
Planned missions |
| ||||||||||||||||
Proposed missions |
| ||||||||||||||||
Cancelled / concepts |
| ||||||||||||||||
See also |
| ||||||||||||||||
|
← 1967 · Orbital launches in 1968 · 1969 → | |
---|---|
Surveyor 7 | Explorer 36 | Kosmos 199 | OPS 1965 | OPS 5028 | Kosmos 200 | Apollo 5 | OPS 2243 · OPS 6236 | Kosmos 201 | E-6LS No.112 | Kosmos 202 | Kosmos 203 | OPS 7034 | Zond 4 | OGO-5 | Kosmos 204 | Kosmos 205 | Explorer 37 | DS-U1-Ya No.1 | OPS 5057 | Kosmos 206 | OPS 4849 · OPS 7076 | Kosmos 207 | Kosmos 208 | Kosmos 209 | Kosmos 210 | Apollo 6 | OV1-13 · OV1-14 | Luna 14 | Kosmos 211 | Kosmos 212 | Kosmos 213 | OPS 5165 | Kosmos 214 | Kosmos 215 | Kosmos 216 | Molniya-1 No.10 | 7K-L1 No.7L | Kosmos 217 | Kosmos 218 | Kosmos 219 | OPS 1419 | Kosmos 220 | ESRO-2B | Nimbus B · SECOR 10 | OPS 7869 | Kosmos 221 | Kosmos 222 | Kosmos 223 | Kosmos 224 | Sfera No.12L | OPS 5138 | Kosmos 225 | Kosmos 226 | IDCSP 20 · IDCSP 21 · IDCSP 22 · IDCSP 23 · IDCSP 24 · IDCSP 25 · IDCSP 26 · IDCSP 27 | Strela-2 No.3 | Kosmos 227 | OPS 5343 · OPS 5259 | Kosmos 228 | Kosmos 229 | Explorer 38 | Kosmos 230 | Molniya-1 No.13 | Kosmos 231 | OV1-15 · OV1-16 | Kosmos 232 | Kosmos 233 | Kosmos 234 | OPS 2222 | OPS 5187 | OPS 5955 | Explorer 39 · Explorer 40 | Kosmos 235 | ATS-4 | ESSA-7 | Orbiscal 1 · OV5-8 · Gridsphere 1 · Gridsphere 2 · Gridsphere B · Gridsphere R · LCS-3 · LIDOS · SECOR 11 · SECOR 12 · Radcat · P68-1 | Kosmos 236 | Kosmos 237 | Kosmos 238 | Kosmos 239 | OPS 5247 | Kosmos 240 | Zond 5 | Kosmos 241 | OPS 0165 · OPS 8595 | Intelsat III F-1 | Kosmos 242 | Kosmos 243 | LES-6 · OV2-5 · ERS-21 · ERS-28 | Kosmos 244 | Kosmos 245 | ESRO-1A | Molniya-1 No.14 | OPS 0964 | Kosmos 246 | Kosmos 247 | Apollo 7 | Kosmos 248 | Kosmos 249 | OPS 4078 | Soyuz 2 | Soyuz 3 | Kosmos 250 | Kosmos 251 | Kosmos 252 | OPS 1315 | OPS 5296 | Pioneer 9 · ERS-31 | Zond 6 | Kosmos 253 | Proton 4 | Kosmos 254 | Kosmos 255 | STV-1 | Kosmos 256 | Kosmos 257 | OPS 6518 | HEOS-1 | OAO-2 | Kosmos 258 | OPS 4740 · OPS 7684 | Kosmos 259 | ESSA-8 | Kosmos 260 | Intelsat III F-2 | Kosmos 261 | Apollo 8 | Kosmos 262 | |
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in brackets. |
Soviet crewed lunar programs | ||
---|---|---|
Launch vehicles and ascent/upper stages |
| ![]() |
Spacecraft |
| |
Other hardware |
| |
Soyuz docking tests | ||
Zond (7K-L1/L1S) lunar flyby missions |
| |
LOK (7K-LOK/L1E) test missions |
| |
LK Lander (T2K) test missions | ||
The † sign designates failed missions. Italics designates cancelled missions. |