Soyuz 7K-L1
Soviet circumlunar spacecraft for crewed Moon flybys.
The Soyuz 7K-L1 "Zond" spacecraft was a modified version of the Soyuz 7K-OK, designed for the Soviet crewed Moon-flyby program. It was intended to carry two cosmonauts from Earth to circle the Moon without entering lunar orbit. Modifications included replacing the orbital module with a support cone and a high-gain parabolic antenna, removing a reserve parachute, and adding a gyro platform and star navigation sensors for far space navigation.
Quick Facts
- Country
- Soviet Union
- Applications
- Carry cosmonauts around the Moon and back to Earth
- Manufacturer
- OKB-1
- Lifetime
- Seven days
- Derivedfrom
- Soyuz 7K-OK
- Built
- 15
- Launched
- 12
- Retired
- 3
Facts from the source article.
History
Sergei Korolev first imagined sending people to the Moon by launching parts of a spacecraft on multiple R-7 rockets and putting them together in orbit around Earth. Then Vladimir Chelomei’s much larger UR-500 booster came along, which in theory could do the whole job in a single launch. Chelomei also put forward his own Moon ship, the LK-1, and Soviet leader Nikita Khrushchev signed off on it in August 1964. But just two months later, Khrushchev was removed from power, and Chelomei lost his main supporter. By the end of that year, Korolev brought back his idea for the Soyuz spacecraft, though he hid his real goal by presenting it as an Earth-orbiting test vehicle for practicing rendezvous and docking. In October 1965, only three months before he died, Korolev got official permission to build a crewed lunar spacecraft based on a modified Soyuz. It would be sent toward the Moon on a UR-500 rocket fitted with the Blok D upper stage, which was being developed by his own bureau, OKB-1. Korolev had originally planned to assemble the lunar Soyuz in Earth orbit because he doubted the UR-500 was strong enough to lift the whole thing, and he also worried about crew safety. After his death in January 1966, the new head of OKB-1, Vasily Mishin, argued that the Soyuz could be lightened enough to fly on the UR-500. The first four uncrewed test flights were only partly successful or outright failures; two of them flew under the generic name “Kosmos,” as was common for Soviet test spacecraft. Starting with a mission from 2 to 7 March 1968, later flights of the L1 spacecraft were publicly called “Zond,” a name the Soviets used for deep-space test missions. Once the United States succeeded in sending Apollo 8 around the Moon, the political drive for a Soviet crewed flyby faded. A planned first crewed L1/Zond flight with Alexei Leonov and Valery Bykovsky, set for late 1970, was called off. On top of that, the Proton booster was nowhere near safe enough for people, and its many launch failures made it a poor choice for carrying a crew.
Planned schedule
By 1967, the Soyuz 7K-L1 program had a packed schedule. Missions 2P and 3P were set for March 1967 to test the Blok D stage. Uncrewed lunar flybys followed: 4L in May and 5L in June. Crewed flybys were planned for 6L in June or July, 7L and 8L in August, 9L and 10L in September, and 11L and 12L in October, with 13L held as a backup. In July 1968, officials proposed monthly L1 launches, aiming for the first crewed flight in December 1968 or January 1969 after three or four successful uncrewed missions. By December 1968, three crewed L1 missions were scheduled for March, May, and July 1969. Finally, in September 1969, a single crewed L1 mission was formally set for April 1970.
Test missions
Cosmos 146 (s/n 1) launched on 10 March 1967 as a prototype Soyuz 7K-L1P into a planned highly elliptical Earth orbit. Cosmos 154 (s/n 3) launched on 8 April 1967 and failed into a planned translunar trajectory. Zond 1967A (s/n 4) launched on 27 September 1967; first stage RD-253 failed, resulting in deviation from flight path at T+67 seconds. Zond 1967B (s/n 5) launched on 22 November 1967; second stage RD-210 failure, shutoff 4 seconds after ignition, launcher crashed downrange. Zond 4 (s/n 6) launched on 2 March 1968 to study remote regions of circumterrestrial space and develop new systems; it returned on 7 March 1968 but the self-destruct system automatically blew up the capsule at 10 to 15 km altitude off the African coast at Guinea. Zond 1968A (s/n 7) launched on 23 April 1968; second stage failed 260 seconds after launch, attempted lunar flyby. Zond 1968B (s/n 8) launched on 21 July 1968; Blok D stage exploded on the pad, killing three people. Zond 5 (s/n 9) launched on 15 September 1968, performed a circumlunar flight on 18 September 1968, the first Moon mission to include animals, and returned to Earth on 21 September 1968. Zond 6 (s/n 12) launched on 10 November 1968, circumlunar on 14 November 1968, returned to Earth on 17 November 1968 but crashed due to parachute failure. Zond 1969A (s/n 13) launched on 20 January 1969; stage two shut down 25 seconds early, automatic abort, capsule safely recovered, attempted lunar flyby. Zond-M 1 launched on 21 February 1969; first stage failure, capsule escape system fired 70 seconds after launch, capsule recovered, attempted lunar orbiter and N1 rocket test. Zond-M 2 launched on 3 July 1969; first stage failure, Zond capsule recovered, attempted lunar orbiter and N1 rocket test. Zond 7 (s/n 11) launched on 7 August 1969, lunar flyby on 11 August 1969, returned to Earth on 14 August 1969. Zond 8 (s/n 14) launched on 20 October 1970, lunar flyby on 24 October 1970, returned to Earth on 27 October 1970. Zond 9 (s/n 10) and Zond 10 (s/n 15) were planned but cancelled.
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