On May 25, 1961, U.S. President John F. Kennedy stood before a special joint session of Congress and announced the ambitious goal to land an American on the Moon before the decade’s end. That same month, the Soviet Union began sketching plans for a super heavy-lift launch vehicle capable of carrying payloads beyond low Earth orbit. Initially conceived to deliver ultra-heavy nuclear weapons such as the Tsar Bomb, the design’s focus soon shifted toward the Moon, aligning Soviet ambitions with those of their Cold War rival.
The result was the N1, one of the largest and most powerful rockets ever conceived, intended to supersede the ICBM-derived launchers then in service. Beyond its military applications, the N1 was intended to launch Soviet cosmonauts to the moon, Mars, and huge space stations into orbit.
A mockup of the N1 rocket at the Baikonur Cosmodrome in late 1967. Credit: Wikimedia Commons
Yet unlike America’s Saturn V, the Soviet project began late, suffered chronic underfunding, and was mired in political and technical rivalries among leading designers Sergei Korolev, Valentin Glushko, and Vladimir Chelomei.
When Korolev died unexpectedly in 1966, the program lost its guiding force. Leadership passed to Vasily Mishin, who, though technically capable, lacked Korolev’s authority and political connections. Under his stewardship the N1 struggled with persistent technical failures and endless delays. Between 1969 and 1972, four launch attempts all ended in disaster. By 1974, just five years after Apollo 11’s triumph, the project was cancelled outright. The Soviet dream of a Moon landing never materialized and for years, officials went so far as to deny that such a massive program had ever existed.
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The N1, when paired with its L3 lunar payload, stood an imposing 105 meters tall—slightly shorter than the Saturn V’s 110 meters. The complete N1-L3 system was composed of five stages: the first three (collectively the N1) to place the vehicle into low Earth orbit, and two additional stages (the L3 complex) to propel the payload toward the Moon and guide it into lunar orbit. Fully fuelled, the rocket weighed an enormous 2,750 tonnes. Its lower stages formed a distinct conical profile, dictated by the arrangement of its propellant tanks, with a base measuring 17 meters across. In terms of capability, the N1 was designed to deliver about 95 metric tons to low Earth orbit—a remarkable figure, though still well short of the Saturn V’s 140.6 metric tons.
Size comparison of N1 and Saturn V. Credit: Wikimedia Commons
The heart of the vehicle was its massive first stage, Block A. With 30 NK-15 engines firing together, it generated 45,400 kilonewtons of thrust at lift-off, making it the most powerful rocket stage ever flown at the time, outstripping even the Saturn V’s 33,700 kilonewtons. That record endured for more than half a century, until SpaceX’s Super Heavy booster finally surpassed it in 2023.
The first flight-ready N1, designated 3L, was rolled out to the pad in May 1968 and, after months of preparation, scheduled for launch on February 21, 1969. Trouble began almost immediately after lift-off. Several of the thirty engines failed, triggering propellant leaks and fire. Less than a minute into flight, the entire first stage shut down, and the rocket fell back to Earth in a fiery crash.
The second attempt, 5L, carried a dummy spacecraft, a fully functional fourth and fifth stage, and an escape system for the crew module. The mission was designed as a rehearsal of a circumlunar flight. Instead, the rocket barely cleared the tower before disaster struck. There was a flash of light, following which the vehicle pitched over, and it slammed back into the launch complex. The resulting explosion shattered windows across the site and hurled debris as far as ten kilometers.
The next launch, N1 6L, occurred almost two years after the previous. This time the rocket rose smoothly but soon developed a severe roll that accelerated uncontrollably. Within seconds the stress tore the vehicle apart in midair.
The final flight, 7L, lifted off on November 23, 1972. The start and lift-off went well, and the N1 7L flew higher and longer than the previous three missions. However, just like the three preceding missions, technical problems caused the rocket to explode, bringing to an end the highly anticipated crewed mission to the moon. By then, the Americans had already put twelve men on the moon. The space race was lost and Moscow cancelled the entire N1 program.
An N1 rocket in the factory showing the 30 rocket engines of its first stage. Credit: Reddit
A number of factors contributed to the failure of N1 program:
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Engine reliability. The rocket’s first stage, Block A, relied on thirty NK-15 engines. Though clustering many smaller engines promised redundancy in theory, in practice the design proved unmanageable. The engines were new, unproven, and suffered from a high failure rate. Their dense plumbing, extreme vibration environment, and the complexity of the monitoring system (KORD) created as many problems as they solved, leading to cascading failures rather than graceful recoveries.
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Rushed development and lack of full testing. Driven by the need to keep pace with Apollo, the N1 was pushed forward under tight deadlines and chronic budget constraints. Most critically, the Soviets never performed a full-scale static firing of the thirty-engine first stage. No test stand at Baikonur could handle the enormous thrust, and schedule pressures discouraged building one. As a result, dangerous interactions between engines—ignition transients, fluid instabilities, and pogo oscillations—were discovered not on the ground but in flight, with catastrophic results.
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Fragmented system integration. The Soviet space program operated through a patchwork of design bureaus, factories, and ministries that often competed rather than collaborated. Poor coordination across these organizations made integration of the N1’s many systems inconsistent and error-prone, with critical problems left unresolved until launch attempts.
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Political and institutional pressures. The N1 developed under constant political strain. As Apollo missions advanced, pressure mounted in Moscow to demonstrate quick results. Shifts in leadership—both at the top of the Soviet state (from Nikita Khrushchev to Leonid Brezhnev) and within the space program itself (from Sergei Korolev to Vasily Mishin)—redefined priorities and disrupted continuity. Rivalries among powerful designers such as Korolev, Glushko, and Chelomei further fractured the program, ensuring that resources and attention were never fully concentrated on the N1.
On paper, the N1’s first stage was the most powerful ever flown until the 2020s; in practice, the Saturn V’s simpler five-engine F-1 cluster, massive ground-test campaign, and program stability produced a reliable Moon rocket in time to meet a political deadline. The N1’s architecture could have succeeded given time, funding, and modern systems engineering—but it didn’t get those conditions.
For decades, the USSR denied there had ever been a Moon race, and details of N1/L3 remained hidden until the late 1980s and 1990s. Only with the release of memoirs and archival material did the outside world gain a granular picture of the technical and managerial struggles behind the veil.
Two N1 rockets stand on the launch pad. Credit: Russian Space web
After the program ended, Soviets scrapped most N1 hardware, but Nikolai Kuznetsov quietly warehoused dozens of upgraded engines. In the 1990s many were sold to the United States; Aerojet modified them as AJ26 for Orbital’s Antares rocket. After the 2014 Antares (ORB-3) launch failure, Orbital replaced AJ26s with a different Russian engine family. Meanwhile, Russia flew NK-33s domestically on Soyuz-2-1v into the 2020s.
The N1’s direct line ended, but its lessons fed forward. Clustering many engines has returned in modern super-heavies—but paired with exhaustive ground testing, robust engine-out strategies, and digital control systems that learn from thousands of hot-fires before flight. And the NK-family’s oxygen-rich staged-combustion heritage helped normalize what is now a standard in high-performance kerolox engines worldwide.
References:
# “N1: The Rise and Fall of the USSR's Moon Rocket”, Spaceflight Histories
# N1, Astronautix
# “The N1 Moon rocket”. Russian Space Web
# “Why did the Soviet Union decide to use 30 small engines instead of a few large ones on the N1?”. Stack Exchange
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