The super-heavy carrier rocket N-1 was nicknamed "Tsar-rocket" for its large dimensions (launch weight of almost 2500 tons, height - 110 meters), as well as the goals set during work on it. The rocket was supposed to help strengthen the state's defense capability, promote scientific and national economic programs, as well as manned interplanetary flights. However, like their famous namesakes - Tsar Bell and Tsar Cannon - this design product was never used for its intended purpose.
The USSR began to think about the creation of a heavy super-rocket back in the late 1950s. Ideas and assumptions for its development were accumulated in the royal OKB-1. Among the options was the use of a design reserve from the R-7 rocket that launched the first Soviet satellites and even the development of a nuclear propulsion system. Finally, by 1962, the expert commission, and later the country's leadership, chose an arrangement with a vertical rocket design, which could put a load weighing up to 75 tons into orbit (the mass of the cargo thrown to the Moon is 23 tons, to Mars - 15 tons). At the same time, it was possible to introduce and develop a large number of unique technologies - an on-board computer, new welding methods, lattice wings, an emergency rescue system for astronauts and much more.
Initially, the rocket was intended to launch a heavy orbital station into near-earth orbit, with the subsequent prospect of assembling TMK, a heavy interplanetary spacecraft for flights to Mars and Venus. However, later, a belated decision was made to include the USSR in the "lunar race" with the delivery of a man to the lunar surface. Thus, the program to create the N-1 rocket was accelerated and it actually turned into a carrier for the LZ expeditionary spacecraft in the N-1-LZ complex.
Before deciding on the final layout of the launch vehicle, the creators had to evaluate at least 60 different options, from multi-block to monoblock, both parallel and sequential division of the rocket into stages. For each of these options, appropriate comprehensive analyzes of both advantages and disadvantages were carried out, including a feasibility study of the project.
In the course of preliminary research, the creators were forced to abandon the multi-block scheme with parallel division into stages, although this scheme had already been tested on the R-7 and made it possible to transport ready-made elements of the launch vehicle (propulsion systems, tanks) from the plant to the cosmodrome by rail … The rocket was assembled and checked on site. This scheme was rejected due to the non-optimal combination of mass costs and additional hydro, mechanical, pneumatic and electrical connections between the missile blocks. As a result, a monoblock scheme came to the fore, which assumed the use of liquid-propellant rocket engines with pre-pumps, which made it possible to reduce the wall thickness (and hence the mass) of the tanks, as well as to reduce the boost gas pressure.
The project of the N-1 rocket was in many ways unusual, but its main distinguishing features were the original scheme with spherical suspended tanks, as well as a load-bearing outer skin, which was supported by a power set (an airplane scheme of "semi-monococks" was used) and an annular arrangement of a liquid-propellant rocket engine at each of the stages. Thanks to this technical solution, as applied to the first stage of the rocket during the launch and its ascent, the air from the surrounding atmosphere was ejected into the inner space under the tank by the LPRE exhaust jets. The result was a semblance of a very large jet engine that included the entire lower part of the 1st stage structure. Even without air afterburning the LPRE exhaust, this scheme provided the rocket with a significant increase in thrust, increasing its overall efficiency.
The stages of the N-1 rocket were interconnected by special transitional trusses, through which gases could flow absolutely freely in the event of a hot start of the engines of the next stages. The rocket was controlled along the roll channel with the help of control nozzles, into which the gas was fed, discharged there after the turbopump units (TNA), along the pitch and course channels, the control was carried out using the thrust mismatch of the opposite liquid-propellant engines.
Due to the impossibility of transporting the stages of a super-heavy rocket by rail, the creators proposed to make the outer shell of the N-1 detachable, and to produce its fuel tanks from sheet blanks ("petals") already directly at the cosmodrome itself. Initially, this idea did not fit into the minds of the members of the expert commission. Therefore, having adopted the preliminary design of the N-1 rocket in July 1962, the members of the commission recommended that the issues of delivery of the assembled rocket stages be further worked out, for example, using an airship.
During the defense of the preliminary design of the rocket, the commission was presented with 2 versions of the rocket: using AT or liquid oxygen as an oxidizer. In this case, the option with liquid oxygen was considered as the main one, since the rocket using AT-UDMH fuel would have lower characteristics. In terms of value, the creation of a liquid oxygen engine seemed to be more economical. At the same time, according to representatives of OKB-1, in the event of an emergency on board the rocket, the oxygen option seemed safer than the option using an AT-based oxidizer. The creators of the rocket remembered the crash of the R-16, which occurred in October 1960 and worked on self-igniting toxic components.
When creating a multi-engine version of the N-1 rocket, Sergei Korolev relied, first of all, on the concept of increasing the reliability of the entire propulsion system, through the possible shutdown of defective liquid-propellant engines during flight. This principle has found its application in the engine control system - KORD, which was designed to detect and turn off faulty engines.
Korolev insisted on the installation of the liquid-propellant engine of the engines. Lacking the infrastructural and technological capabilities of the costly and risky creation of advanced high-energy oxygen-hydrogen engines and advocating the use of more toxic and powerful heptyl-amyl engines, the leading engine building bureau Glushko did not engage in engines for H1, after which their development was entrusted to the Kuznetsov KB. It is worth noting that the specialists of this design bureau managed to achieve the highest resource and energy perfection for oxygen-kerosene type engines. At all stages of the launch vehicle, the fuel was located in the original ball tanks, which were suspended from the supporting shell. At the same time, the engines of the Kuznetsov Design Bureau were not powerful enough, which led to the fact that they had to be installed in large quantities, which ultimately led to a number of negative effects.
The set of design documentation for the N-1 was ready by March 1964, flight design tests (LKI) were planned to begin in 1965, but due to the lack of funding and resources for the project, this did not happen. Affected by the lack of interest in this project - the USSR Ministry of Defense, since the payload of the rocket and the range of tasks were not specifically designated. Then Sergei Korolev tried to interest the political leadership of the state in the rocket by proposing to use the rocket in the lunar mission. This proposal was accepted. On August 3, 1964, the corresponding government decree was issued, the start date of the LKI on the rocket was shifted to 1967-1968.
To carry out the mission to deliver 2 cosmonauts to the lunar orbit with the landing of one of them on the surface, it was required to increase the rocket carrying capacity up to 90-100 tons. This required solutions that would not lead to fundamental changes in the draft design. Such solutions were found - installation of additional 6 LPRE engines in the central part of the bottom of block "A", changing the launch azimuth, lowering the height of the reference orbit, increasing the filling of fuel tanks by supercooling the fuel and oxidizer. Thanks to this, the carrying capacity of the N-1 was increased to 95 tons, and the launch weight increased to 2800-2900 tons. The draft design of the N-1-LZ rocket for the lunar program was signed by Korolev on December 25, 1964.
The next year, the rocket scheme underwent changes, it was decided to abandon the ejection. The air flow was closed by the introduction of a special tail section. A distinctive feature of the rocket was the massive payload recoil, which was unique to Soviet missiles. The entire load-bearing scheme worked for this, in which the frame and tanks did not form a single whole. At the same time, a rather small layout area, due to the use of large spherical tanks, led to a decrease in payload, and on the other hand, extremely high engine characteristics, extremely low specific gravity of the tanks and unique design solutions increased it.
All stages of the rocket were called blocks "A", "B", "C" (in the lunar version they were used to launch the spacecraft into near-earth orbit), blocks "G" and "D" were intended to accelerate the spacecraft from the Earth and decelerate at the Moon. The unique scheme of the N-1 rocket, all stages of which were structurally similar, made it possible to transfer the test results of the 2nd stage of the rocket to the 1st. Possible contingencies that could not be “caught” on the ground were supposed to be checked in flight.
On February 21, 1969, the first rocket launch took place, followed by 3 more launches. All of them were unsuccessful. Although in the course of some bench tests, the NK-33 engines proved to be very reliable, most of the problems that arise were associated with them. The problems of the H-1 were associated with the reversing torque, strong vibration, hydrodynamic shock (when the engines were turned on), electrical interference and other unaccounted for effects that were caused by the simultaneous operation of such a large number of engines (at the first stage - 30) and the large dimensions of the carrier itself. …
These difficulties could not be established before the start of the flights, since in order to save money, expensive ground stands were not produced for conducting fire and dynamic tests of the entire carrier or at least its 1st stage in the collection. The result of this was the testing of a complex product directly in flight. This rather controversial approach ultimately led to a series of launch vehicle accidents.
Some attribute the failure of the project to the fact that the state did not have a definite clear position from the very beginning, like Kennedy's strategic stake on the lunar mission. Sharakhanya of Khrushchev's and then Brezhnev's leadership in relation to effective strategies and tasks of cosmonautics are documented. So one of the developers of "Tsar-rocket" Sergei Kryukov noted that the N-1 complex died not so much because of technical difficulties, but because it became a bargaining chip in the game of personal and political ambitions.
Another veteran of the industry, Vyacheslav Galyaev, believes that the determining factor of failures, in addition to the lack of due attention from the state, was the banal inability to work with such complex objects, while achieving the approval of quality and reliability criteria, as well as the unpreparedness of Soviet science at that time for implementation of such a large-scale program. One way or another, in June 1974, work on the N1-LZ complex was stopped. The backlog available under this program was destroyed, and the costs (in the amount of 4-6 billion rubles in 1970 prices) were simply written off.
