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Soviets mulled a colossal nuke on future Moon rocket
Nuclear scientists and rocket engineers in the USSR discussed a possibility of deploying the largest hydrogen bomb of all times on a planned N1 heavy-lifting rocket, recent memoirs of a top Soviet nuclear program veteran say. Immediately after the unprecedented 50-megaton device had successfully exploded in an arctic test in 1961, it became a major justification for the development of a giant rocket to deliver it to its target, Aleksandr Chernyshev, Deputy Chief at the Russian Nuclear Center, RFYaTs, wrote.
The Cold War-era N1 heavy-lifting rocket could carry world's most-powerful hydrogen warhead inside its payload section. Alternatively, it could be equipped with 17 warheads.
From the time a veil of secrecy had fallen from the Russian rocket industry in 1990s, its sources have maintained that Sergei Korolev, the founder of the Soviet space program, tried to lure the Defense Ministry into funding his dream rocket project with proposals for its military use, including carrying nuclear weapons -- a rather unlikely task for such a huge booster. (74) But recently, a key figure from a traditionally much more secretive nuclear field confirmed the enormity of the weapon that was planned to be carried on the N1. Even more importantly, the expert also put a date on the discussions to put a nuclear warhead on what would eventually become the Soviet "Moon rocket."
On Oct. 30, 1961, the USSR exploded an experimental hydrogen bomb designated A602EN on the island of Novaya Zemlya in the Arctic Ocean. Although the 50-megaton blast was about three times more powerful than the largest US nuclear charge tested at the time, the new Soviet bomb was actually "toned down" to a half of energy it was capable of unleashing.
The resulting 100-megaton hydrogen bomb would never be operationally deployed and its spectacular test served mostly political and engineering purposes. However, Korolev wasted no time using the arrival of the "Tsar-bomb", as it was later described, as a yet another military rational for the N1 launcher. Korolev was hardly a war-monger and wanted the heavy rocket to fulfill his space ambitions, however the N1 and its vast launch pads would be virtually impossible to build without military support.
According to Chernyshev, in November and December 1961, just one or two months after the "birth" of a mega-bomb, its developers were already in Korolev's offices discussing a possibility of "packaging" their wonder weapon into the N1 rocket. The A602EN bomb dropped from the aircraft over Novaya Zemlya had a length of eight meters, a diameter of 2.1 meters and a mass of 26 tons. Since the rocket-based warhead would need a massive heat shield to protect the nuclear charge from the heat of atmospheric reentry, the mass of the prospective payload would increase considerably. Estimates based on known depictions of the military version of the N1, indicate that the roughly 70-meter-tall rocket would have a payload area with a diameter of at least 4.1 meters and an approximate length of around 10 meters. The launcher was expected to carry 75-80 tons to a low Earth orbit.
Rocket engineers jokingly nick-named a proposed nuclear warhead for the N1 rocket "Kuzkina mat" (Mother of Kuzma), after a semi-profane, semi-humorous expression used by the Soviet leader Nikita Khrushchev in his infamous anti-US rants.
In parallel with the discussions about using the N1 rocket as a delivery system, nuclear scientists also proposed to test the device at its full 100-megaton capacity. (643) Unfortunately for Korolev (but probably not for the world piece), neither idea was ever approved.
Other military tasks for N1
Launching the mega-bomb was neither the first nor the last military job thought up by Korolev for the N1. Other potential tasks included the delivery of multiple warheads (as many as 17) and the launch of a giant military space station capable of intercepting enemy satellites and even bombarding targets on Earth. Concepts of unmanned anti-missile defense systems were also apparently entertained.
But despite all Korolev's efforts, the N1 rocket did not fit well into the Soviet military doctrine, relying on mass deployment of compact ballistic missiles. To make matters worse, some high-ranking officers within the defense ministry were apparently openly voicing a concern that space program in general and the N1 project in particular would divert scarce funds and attention from pure military goals and thus could compromise the Soviet military readiness. The Ministry of Defense did provide lukewarm backing for low-cost non-military "add-ons" to its existing programs, such as launching scientific satellites on converted ballistic missiles, but it vehemently resisted attempts to make it pay for expensive hardware with dubious military significance.
Despite the skepticism of the military, on June 23, 1960, the Soviet government authorized the preliminary design of the N1 rocket, assigning Ministry of Defense and the industry to come up with a list of military projects suitable for the booster by the third quarter of the same year.
As military continued dragging its feet on the issue, on January 15, 1961, Korolev wrote to Konstantin Rudnev, the head of the State Committee on Defense Technology, GKOT, outlining space projects of high military importance. He also attached a preliminary proposal for an N1-launched military space station identified as OS. The station was described as a "super-reconnaissance" facility capable of automated early warning about rocket launches, nuclear explosions, measurement of solar radiation and other tasks. A total of 14 tasks were formulated for the outpost.
Pointing at the US, Korolev reiterated that the N1 would enter service after the introduction of the American Saturn and, possibly, Nova rocket. In the letter, Korolev admitted that "...at the first sight, some of the proposals might appear questionable and, to some extent, even fantastic..." He urged not jump to conclusions, reminding about the remarkable progress made by aviation in the past 25 years.
Korolev stressed that the development of the N1 was the most important to the military among all other space projects and should've been be accelerated as much as possible.
Along with a letter to Rudnev, Korolev appealed to Marshall Kirill Moskalenko, the commander of the Strategic Rocket Forces, urging the Ministry of Defense to accelerate the formulation of military goals for the heavy launcher in "...at least very preliminary and open to modification" form.
Korolev's correspondence shows that as late as February 1962, he was still unable to overcome the reluctance of the military to endorse the enormous size and payload capabilities of the N1 rocket.
By that time, Korolev was still proposing to use the N1 for the delivery of multiple military payloads into orbit but he also increasingly relied on the argument about the work on similar projects across the Atlantic. He instructed his associates involved in the lobbying effort before the Ministry of Defense to quote the highest possible payload numbers estimated for American Saturn and Nova rockets, and even cite Wernher von Braun's utopian proposal for a manned Martian expedition featuring a rocket with a launch mass of 7,000 tons.
However to his colleagues, Korolev made no secret of the real goals determining the payload capability of the N1 rocket, namely launching the TMK spacecraft on missions to the vicinity of the Moon, Mars and Venus. Particularly Korolev quoted requirements for a two-way missions around the Moon and the expedition on its surface.
A month later, Korolev tried a slightly different approach in dealing with the military skepticism toward the N1. On March 5, he sent a letter to top officials at the Ministry of Defense, rocket industry and nuclear ministry, proposing to precede N1 with a smaller N2 rocket (identified in the document as H-2) which would be more useful to the military.
The 750-ton, three-stage N2 rocket would be built out of two upper stages of the N1 (apparently with a custom-designed third stage). The vehicle would be capable of delivering 25 tons of payload to the low Earth orbit. Korolev proposed it as a carrier of an unspecified number of 25-megaton nuclear warheads capable of hitting their targets with an accuracy of two kilometers. He specified that the rocket would work either as a traditional ICBM flying a ballistic trajectory or as a "global" rocket, implying the delivery of warheads to the Earth orbit from where they would dive toward their targets. One version of the "global" rocket would carry 6-7 warheads with a yield of 2.2 megatons and an accuracy of five kilometers along its flight trajectory and three kilometers sideways.
The N2 would be also used as a space launcher for military spacecraft, but more importantly, it would pave the way to the development of the N1.
The development of the N2 rocket would be further simplified by borrowing the NK-9 engine from the R-9M ballistic missile. At the time, NK-9 was expected to complete its live firing tests in the first half of 1962. The proposed development schedule would enable the first launch of the N2 rocket from the existing launch pad of the R-7 rocket in Tyuratam no later than the end of 1963. It would be followed by the N1 by the end of 1964 or beginning of 1965, Korolev wrote.
Specifications of the N family of rockets (as of March 1962):
Next chapter: Proton rocket
Written and illustrated by Anatoly Zak; Last update: November 3, 2018
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At the end of the 1950s, American plans for the development of giant rockets, such as Nova (above), and their perceived military significance prompted Khrushchev to act. However, the Soviet defense ministry, which funded the rocket programs, remained cool to the idea of big missiles, preferring compact ICBMs instead.
The world's largest thermonuclear explosion conducted by the USSR on Oct. 30, 1961, as viewed from an aircraft flying between 39 and 53 kilometers from the epicenter. Credit: RFYaTs-VNIIEF
During the record-breaking thermonuclear test, a four-engine Tu-95 aircraft dropped a 26-ton mega-bomb from an altitude of 11.5 kilometers. Copyright © 2009 Anatoly Zak
A replica of the 100-megaton A602EN hydrogen bomb (top right) next to a several nuclear missile warheads on the background. Credit: RFYaTs-VNIIEF
A purported exterior design of the giant ICBM based on the N1 rocket. Copyright © 2013 Anatoly Zak
Scale models which were seen at the technical school in Korolev appear to show deriviatives of the N1 design. Click to enlarge. Credit: Jaap Terweij