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Artist's impression of the Soyuz 7K-L1 en route to the Moon.
An L1 lunar complex with Proton booster top stage is being prepared in the assembly hangar
Proton booster with L1 spacecraft rollout
The Soyuz 7K-L1 "Zond" spacecraft was designed to launch men from the Earth to circle the Moon without going into lunar orbit in the context of the Soviet manned moon-flyby program in Moon race. It was based on the Soyuz 7K-OK with several components stripped out to reduce the vehicle weight. The most notable modifications included the removal of the orbital module (the orbital module was replaced by a support cone and a high gain parabolic antenna) and a reserve parachute; and the addition of the gyro platform and star navigation sensors for the far space navigation. The spacecraft was capable of carrying two cosmonauts. In the beginning there were serious reliability problems with both the new Proton rocket, the Proton 7K-L1, and the similar new Soyuz spacecraft. With the first four unmanned test starts (see below) being partially successful or unsuccessful, including two under common open name "Kosmos" as for any Soviet test spacecraft, the mission of 2–7 March 1968 and subsequent ones were the flights of the L1 spacecraft under the open designation "Zond" that were given by Soviets for test missions to far space.
After the successful US Apollo 8 manned flight around Moon, the Soviet manned moon-flyby missions lost political motivation. The first manned flight of the L1/Zond spacecraft with Alexey Leonov and Valery Bykovsky planned for the end of 1970 was cancelled.
All L1/Zond spacecraft made only unmanned automatic flights from 1967–1970, from (Zond 4 to Zond 8), and four of these five Zond flights suffered malfunctions.
Test flights conducted around the Moon showed problems using their star sensors for navigation. These problems caused ballistic reentry due to the failed guidance. One direct descent re-entry was performed on a steep ballistic trajectory with deceleration of up to 20 Gs and splashed down in the Indian Ocean. Three others performed a maneuver known as "skip reentry" to shed velocity. One of those also performed an unsafe (for humans) descent of up to 20 Gs of deceleration, the other suffered main parachute failure, and only one flight - Zond 7 - would have been safe for cosmonauts.
Instrumentation flown on these missions gathered data on micrometeor flux, solar and cosmic rays, magnetic fields, radio emissions, and solar wind. Many photographs were taken and biological payloads were also flown. Zond 5 was the first spacecraft to carry a group of terrestrial creatures (tortoises being the most complex) on a circumlunar flight and return relatively safely to Earth. Zond 5 splashed down in the Indian Ocean after descending steeply with a 20 G deceleration rate. Although unsafe for humans these high Gs apparently didn't affect the tortoises' health, and they were reportedly able to breed afterwards.
Two modifications of main Soyuz 7K-L1 "Zond" version were created: the powered (up to 7 tonn mass) Soyuz 7K-L1S "Zond-M" that were failed attempted to launch for Moon flyby on N1 rocket two times due to Soyuz 7K-LOK orbital ship-module of L3 lunar expedition complex was not ready; the Soyuz 7K-L1E "Zond-LOK" as dummy mockup of Soyuz 7K-LOK and were successfully launched on Low Earth Orbit on Proton rocket as Kosmos 382 and failed launched for Moon orbiting on third N1 rocket.
Despite of closest readyness for primary goal, no official open name for manned Soyuz 7K-L1 "Zond" was adopted. According to Mishin's and Kamanin's memoires, the names "Rodina" (motherland), "Ural" (Ural mountains), "Akademik Korolyov" (academician Korolyov). Also, "Zarya" (dawn) and "Znamya" (banner) were proposed for both lunar Soyuz 7K-L1 flyby and Soyuz 7K-LOK orbital ships.
The information display systems (IDS) on the L1 was called "Saturn" and featured some differences from the standard 7K-OK "Sirius-7K" IDS.
Along with the remaining 7K-L1s, the Soviet moon-flyby program was closed in 1970 without the achievement of its manned primary goal. The intended manned use of L1/Zond spacecraft was documented in official Soviet sources at first time but from 1968 until 1989 this and the moon-landing N1-L3 programs were classified and the Soviet government denied the existence of both. Near 1968 a rare open Soviet sources (Big Soviet Encyclopedia's Yearbook, Kosmonavtika small encyclopedia) sporadically referred to Zond's as tests of space ships for lunar missions (omitting but meaning words manned - in difference to term space apparate used by Soviets for non-manned spacecraft).
Proton 7K-L1 launch vehicle configuration
As of 1967, the Soyuz 7K-L1 launch schedule was:
- 2P -Develop Block D stage -Feb or Mar 67
- 3P -same -Mar 67
- 4L -Unmanned lunar flyby -May 67 (actually launched on September 27, 1967, booster failure)
- 5L -Unmanned lunar flyby -Jun 67 (actually launched on November 22, 1967, booster failure)
- 6L -Manned lunar flyby -Jun or Jul 67
- 7L&8L -Manned lunar flybys -Aug 67 (7L actually launched on April 23, 1968 as Zond 1968A, booster failure; 8L actually launched on July 21, 1968, booster explosion)
- 9L&10L -Manned lunar flybys -Sep 67 (10L planned to launch as Zond 9, cancelled)
- 11L&12L -Manned lunar flybys -Oct 67
- 13L -Reserve spacecraft (actually launched on January 20, 1969 as Zond 1969A, booster failure;)
In July 1968 it was proposed that L1 spacecraft would be launched every month, and the first manned mission would be in December 1968 or January 1969 after 3-4 successful unmanned flights. In December 1969 dates for three manned L1 missions were set to March, May, and July 1969. Finally, in September 1969 one manned L1 mission was formally set for April 1970.
Fifteen Soyuz 7K-L1 were built.
- s/n 1 - prototype not equipped with heat shield, intended to perfect orbital operation of the spacecraft without recovery of the capsule. Launched on 1967 March 10 as Cosmos 146
- s/n 2 - prototype not equipped with heat shield, intended to perfect orbital operation of the spacecraft without recovery of the capsule.
- s/n 3 - Launched on 1967 April 8 as Cosmos 154
- s/n 4 - launched on September 27, 1967 as Zond 1967A, booster failure
- s/n 5 - launched on November 22, 1967 as Zond 1967B, booster failure
- s/n 6 - launched on 1968 March 2 as Zond 4
- s/n 7 - launched on April 23, 1968 as Zond 1968A, destroyed
- s/n 8 - launched on July 21, 1968, destroyed
- s/n 9 - launched on 1968 September 14 as Zond 5. The return capsule is on display at the Energia Museum, in Russia.
- s/n 10 - planned to launch as Zond 9, canceled
- s/n 11 - launched as Zond 7. The return capsule is on display at Orevo, Russia.
- s/n 12 - launched on November 10, 1968 as Zond 6, returned to Earth on November 17, 1968
- s/n 13 - launched on January 20, 1969 as Zond 1969A, failure, capsule recovered.
- s/n 14 - launched on October 20, 1970 as Zond 8, returned to Earth on October 27, 1970
- s/n 15 - planned to launch as Zond 10, canceled
- Cosmos 146 (Soyuz 7K-L1 s/n 1)
- Launched March 10, 1967
- Prototype Soyuz 7K-L1P launched by Proton into planned highly elliptical earth orbit.
- Cosmos 154 (Soyuz 7K-L1 s/n 3)
- Launched April 8, 1967
- Prototype Soyuz 7K-L1P launched by Proton and failed into planned translunar trajectory.
- Zond 1967A (Soyuz 7K-L1 s/n 4)
- Launched September 27, 1967
- First stage -1 RD-253 failed, resulting at T+67 sec in deviation from flight path.
- Zond 1967B (Soyuz 7K-L1 s/n 5)
- Launched November 22, 1967
- Second stage - 1 x RD-0210 failure, shutoff of stage 4 seconds after ignition. Launcher crashed downrange.
- Zond 4 (Soyuz 7K-L1 s/n 6)
- Launched March 2, 1968
- Study of remote regions of circumterrestrial space, development of new on-board systems and units of space stations.
- Returned to Earth March 7, 1968 - Self-destruct system automatically blew up the capsule at 10 to 15 km altitude, 180–200 km off the African coast at Guinea.
- Zond 1968A (Soyuz 7K-L1 s/n 7)
- Launched April 23, 1968
- Second stage failed 260 seconds after launch.
- Attempted Lunar flyby
- Zond 1968B (Zond 7K-L1 s/n 8)
- Launched July 21, 1968
- Block D stage exploded on pad, killing three people.
- Zond 5 (Soyuz 7K-L1 s/n 5)
- Launched September 15, 1968
- Circumlunar September 18, 1968
- Returned to Earth September 21, 1968
- Zond 6 (Soyuz 7K-L1 s/n 12)
- Launched November 10, 1968
- Circumlunar November 14, 1968
- Returned to Earth November 17, 1968
- Zond 1969A (Soyuz 7K-L1 s/n 13)
- Launched January 20, 1969 (planned December 8, 1968)
- Stage two shutdown 25 seconds early. Automatic flight abort. Capsule was safely recovered.
- Attempted Lunar flyby (planned first manned flight to beat American)
- Zond-M 1
- Launched February 21, 1969
- First stage failure. Capsule escape system fired 70 seconds after launch. Capsule was recovered.
- Attempted Lunar orbiter and N1 rocket test
- Zond-M 2
- Launched July 3, 1969
- First stage failure. Zond capsule was recovered.
- Attempted Lunar orbiter and N1 rocket test
- Zond 7 (Soyuz 7K-L1 s/n 11)
- Launched August 7, 1969
- Lunar flyby August 11, 1969
- Returned to Earth August 14, 1969
- Zond 8 (Soyuz 7K-L1 s/n 14)
- Launched October 20, 1970
- Lunar flyby October 24, 1970
- Returned to Earth October 27, 1970
- Zond 9 (Soyuz 7K-L1 s/n 10)
- Zond 10 (Soyuz 7K-L1 s/n 15)
- ^ http://www.novosti-kosmonavtiki.ru/content/numbers/252/43.shtml (in Russian)