N1 Rocket – The Most Powerful Space Rocket Ever Built
The N1 rocket was developed by the Soviet Union as Russia’s answer to the American Saturn rocket in an era where both sides of the Cold War were trying to stay one step ahead when it came to advancing rocket technology. The N1’s origins began in 1959 when the Soviets wanted to pursue their own Moon landing program and construction on a new launch vehicle began.
The N1 ultimately failed in getting Russian cosmonauts to the moon first due to serious technical issues with its launch process and a troubled design process owing to rivalry and political disputes, but it remains one of the most powerful and ambitious rockets in history to be launched.
Origins of the N1
With the onset of the Cold War, both the Soviet Union and the United States began to invest heavily in new rocket technology that could be used for both ICBM (intercontinental ballistic missile) weapons development and space exploration.
The Nazi regime in Germany had developed their own rocket and cruise missile technology during the Second World War, and following the defeat of the Nazis, both sides sought to use knowledge and designs gleaned from German scientists to further rocket building programs.
The Soviet Union’s space program has been the subject of much fascination and concern in America since Russia’s successful launch of the first satellite Sputnik in 1957 which had been propelled into space using an ICBM that could reach the US mainland.
In the late 1950s, Soviet scientists had also researched the possibility of nuclear powered rockets, such as the YaKhR-2 design, but these were abandoned due to safety concerns and research concluding that traditional chemical based rocket propulsion could still provide the power necessary.
In 1960, Russian rocket scientist Sergei Korolev sent a letter to the central committee of the Communist Party of the Soviet Union arguing for a communist expansion into space in response to growing American advances and requested state funding for a new rocket design.
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In the same year, Korolev made a case to Soviet premier Nikita Khruschev that the Soviet Union could build a rocket capable of completing a moon landing and asked for the creation of a Soviet Institute of Interplanetary Studies to conduct research into a space program. Unfortunately, Korolev also admitted that he had not consulted all Soviet rocket designers on his plan and the idea was refused by Khruschev.
By the 1960s, both the Soviet Union and the United States became locked into a race to see which country would be the first to send a human to the moon.
The Soviet Union had already demonstrated its capabilities in space with the launch of Yuri Gagarin into orbit aboard the Vostok 1 spacecraft in 1961. In November 1967, America conducted a successful test launch of the Saturn V rocket which proved to be technically capable of making the journey to the moon and back. This was followed by a second successful, unmanned test of the Apollo 4 rocket unit.
Korolev was eventually allocated a small amount of funding from the Soviet government in the early 1960s to develop a space program since the Soviet military were unwilling to reallocate funds for non-military purposes due to the arms race at the time.
His initial scheme proposed that Soviet Soyuz rockets be used to complete a space mission, but due to its limited range, multiple Soyuz units would be used in different roles to guide a crew into space. However, it was determined that a rapid launch design was needed to prevent any of the Soyuz stages from burning out of fuel.
Instead, he proposed a larger launch vehicle design which was designated as the N1. In the plans, the N1 was intended as a heavy-lift launch vehicle capable of carrying extensive payloads into orbit and beyond.
Korolev worked closely with former rival scientists Vladimir Chelomey and Valentin Glushko. All three began to combine ideas they had created separately. Chelomey had proposed to the Soviet Communist Party that instead of a physical landing on the moon, a Russian crew would instead perform a close-proximity orbit. Chelomey idea was deemed more acceptable and realistic by the Soviet government and more funding was granted.
After securing fundings, the second obstacle faced by the Soviet engineers was the development of the rocket’s engines and the fuel which could be used. The N1 rocket initially planned to use the NK-15 and NK-33 engines, which were designed to burn a mix of kerosene and liquid oxygen. The NK-15 and NK-33 were extremely powerful, but had been plagued with reliability issues with a high rate of failure during testing.
Various propellant (rocket fuel) ideas were discussed for the N1, including Lox-Kerosene, Lox-UDMH and Nitric Acid-UDMH.
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In 1961, Glushko acquired information from American NASA rocket tests that were using N2O4 as fuel with successful results for the Titan II rocket. He suggested using it in all three stages of the N1. However, Korolev felt N204 was too dangerous and this disagreement led to several clashes between him and Glushko which set the project back with Korolev refusing to use N2O4.
To reach a solution, Korolev enlisted the help of jet engine designer Nikolai Kuznetsov who proposed using the NK-15 engine but powered using Lox-Kerosene fuel. The NK-15 was a smaller engine but would be arranged around the rocket’s base in 30 units to increase its lift power.
To secure more backing for his ideas, Korolev also pitched the N1 as a potential ballistic weapon in addition to a space exploration vehicle in March 1962.
While the idea pleased Soviet military officials, the situation was complicated when Khruschev was ousted from power in 1964 and replaced by new Soviet leader Leonid Brezhnev.
The new government tried to reach a compromise on the project in 1965 by declaring the N1 would perform a close orbital mission of the moon to follow Chelomey’s proposal while Korolev’s N1 design would be used to perform it. Korolev wanted the orbit to be manned and after some hesitation this was approved by the Soviet government Central Committee in 1964.
The Soviet government hoped to time the moon orbit project with the 50th anniversary of the Bolshevik revolution to make it a propaganda display and this would be followed by a moon landing in 1968.
In January 1966, the project was dealt a major blow when Korolev died. He was replaced by his assistant Vasily Mishin who had knowledge of rocket science but lacked Korolev’s political connections.
Design of the N1
Mishin continued with the N1 design at the behest of the Soviet government and in February 1966, a launch pad site was constructed at the Baikonur Cosmodrome and components for the N1 were shipped there in November that year.
The first unit produced was the N1F variant which was a full-scale test model where each rocket stage could be tested.
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The completed design of the new N1 was big but complex, with 30 engines and a total thrust of over 45 million newtons. This would make it the most powerful rocket built at the time with the projected ability to carry up to 95 tons of payload into low Earth orbit.
Testing and launch
In February 1967, the first full N1 rocket was constructed with a projected launch date of March 1968 and an actual moon landing using an N1 set to take place in 1969.
In November 1967, the mock up N1 was readied for initial pre-flight testing before it was dismantled and returned to the launch site in 1968. However, cracks were detected in the first stage rocket and the test model was removed from the launch pad and the intact upper stages were kept for crew training.
An updated N1 was returned to the launch site in January 1969 anticipation for a successful launch the next month. Mishin brought over 2,300 scientists and technicians with him to help prepare and maintain the rocket.
After all the preparation, the first test launch of the N1 rocket finally took place on February 21, 1969. However, the launch was a disaster, with the rocket exploding in the air just seconds after liftoff.
The cause of the explosion was later determined to be a malfunction in one of the rocket’s engines after small metallic particles became lodged in the gas generator turbine of the second stage engine and a subsequent investigation blamed excessive overheating in the engine compartment. The rocket’s KORD (engine control system) had also mistakenly shut down the wrong engine when the problems were detected.
A second N1 launch was attempted in July 1969, but this also ended in failure when the vehicle fell from the launch pad and exploded. The exact cause was disputed between Mishin and Chelomey, with both blaming each other’s design contributions as the cause, but it was generally decided by investigators that an exploding fuel pump had caused the crash.
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To add insult to injury, the Americans had been pressing ahead with their moon landing program and had seen good test results with the Apollo rocket. Both American and British military intelligence had become aware that the Soviets were planning their own moon program after detecting the explosions at the site and the news motivated NASA to intensify their program.
Improvements were made to the N1’s KORD engine detection system and a third launch was attempted in 1971 but also resulted in failure due to a rotation problem. This was followed by a fourth failed launch in 1974.
After the botched launch of the fourth N1 vehicle, Glushko and other scientists were brought before a government tribunal to offer independent views on how the project could be improved.
No one could offer an inexpensive or workable solution. The Soviets ultimately shut down the N1 project in 1974 and cancelled all plans for a fifth launch. Due to the secrecy around the Soviet government, the exact reasons for the decision were never made clear to the public, but it has been speculated that a combination of technical disputes, spiraling costs and political pressure all played a role.
Although the launch site was closed after the project was abandoned, the remains of the N1 rocket program can be seen in the abandoned launch pad at the Baikonur Cosmodrome in Kazakhstan.
Despite the cancellation and failure of the N1 rocket program, it paved the way for future developments in Soviet rocket building. The lessons learned from the N1 program would be applied to the development of the more successful Energia rocket, which was based on the N1’s design and used some of its components.
The Energia was launched in 1987 and was used as a launching vehicle for other projects, including the Buran space shuttle which was the Soviet Union’s answer to NASA’s Space Shuttle program.
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The Energia was also the first rocket to use strap-on boosters which increased the overall thrust of the rocket during liftoff and was later adopted by other rockets, including the American Space Shuttle.