The N1 (from Ракета-носитель Raketa-nositel', "Carrier Rocket"; Cyrillic: Н1, GRAU index: 11A52, Sheldon: G-1-e, DoD: SL-15) was a super heavy-lift launch vehicle of the Soviet space program intended for crewed travel to the Moon and beyond. All four launch attempts between 1969 and 1972 failed. Studied and designed by OKB-1 since 1959, it was the counterpart to the US Saturn V. A five-stage kerolox-fuelled rocket, its Block A was the most powerful rocket stage flown for over 50 years, at 45 meganewtons of thrust, until the SpaceX Super Heavy. Block A's large cluster of thirty NK-15 engines, prone to individual failures, was managed by KORD, an analog computer which shut down engines opposite the failure, to maintain attitude control. Block B and V used eight and four hot staged engines respectively, planned to bring the rocket to low Earth orbit. Dangers of the complex engine cluster and fuel feeder systems were not discovered earlier as static fires were not conducted on the Block A. Its second test flight resulted in one of the largest conventional explosions ever, that disabled its Site 110 launch pad at Baikonur Cosmodrome for 18 months. The N1-L3 aimed to compete with the US Apollo program for a crewed Moon landing, using a similar lunar orbit rendezvous method. The rocket had three stages, carrying the L3 lunar payload into low Earth orbit with two cosmonauts. The L3 contained the Block G trans-lunar injection stage; Block D for mid-course corrections, lunar orbit insertion, and initial surface descent; single-pilot LK lander; and two-pilot Soyuz 7K-LOK orbital spacecraft for return to Earth. The N1 started development in October 1965, almost four years after the Saturn V. The project was derailed by the death of its chief designer Sergei Korolev in 1966; the program was suspended in 1974 and canceled in 1976. The TMK project of crewed Mars and Venus flybys also relied on the N1. OKB-1 later developed Energia, the only Soviet super-heavy lift rocket to reach orbit, flying in 1987 and 1988. Details of the Soviet crewed lunar programs were kept secret until the USSR was nearing collapse in 1989. From 2013, the NK-33 engines, built for the N1F improvement cancelled in 1974, were adapted to the smaller US Orbital Sciences Antares 100 rockets and Russian Soyuz 2.1v rockets.
History In 1967 the United States and the Soviet Union were in a race to be first to land a human on the Moon. The N1/L3 program received formal approval in 1964, which required development of the N1 launch vehicle, comparable in size to the American Saturn V. On 25 November 1967, less than three weeks after the first Saturn V flight during the Apollo 4 mission, the Soviets rolled out an N1 mock-up to the newly constructed launch pad 110R at the Baikonur Cosmodrome in Soviet Kazakhstan. This Facilities Systems Logistic Test and Training Vehicle, designated 1M1, was designed to give engineers valuable experience in the rollout, launch pad integration, and rollback activities, similar to the Saturn V Facilities Integration Vehicle SA-500F testing at the Kennedy Space Center in Florida in mid-1966. While the crawler transported the Saturn V to the pad vertically, the N1 made the trip horizontally and was then raised to the vertical position at the pad, using a purpose built Transporter Erector (TE) named Grasshopper. Using TEs was standard practice in the Soviet space program. On December 11, after completion of various tests, the N1 mockup was lowered and rolled back to the assembly building. The 1M1 was used repeatedly in the following years for additional launchpad integration tests. Although this test was carried out in secret, a US reconnaissance satellite photographed the N1 on the pad shortly before its rollback to the assembly building. NASA Administrator James Webb had access to this and other similar intelligence that showed that the Russians were seriously planning crewed lunar missions. That knowledge influenced several key US decisions in the coming months. The satellite imagery appeared to show the USSR was close to a flight test of the N1, but did not reveal that this particular rocket was just a mockup and that the USSR was many months behind the US in the race to land a human on the Moon (however, the CIA the NRO, and President Lyndon B. Johnson did know that the rocket was a mock-up per the daily presidential briefing of 27 December 1967). The Soviets were hopeful that they could carry out a test flight of the N1 in the first half of 1968, but for a variety of technical reasons the attempt did not occur for more than a year.
Early Soviet lunar concepts
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