Russia is in dire need of a super-heavy class carrier
Last year, Roscosmos announced a tender for the development of a heavy-class rocket based on the existing Angara project, capable, among other things, of delivering a manned spacecraft to the moon. Obviously, Russia's lack of super-heavy rockets capable of throwing up to 80 tons of cargo into orbit is hampering many promising work in space and on Earth. The project of the only domestic carrier with similar characteristics, Energia-Buran, was closed in the early 90s, despite the spent 14.5 billion rubles (in prices of the 80s) and 13 years. Meanwhile, in the USSR, a super-rocket with stunning performance characteristics was successfully developed. The readers of "VPK" are offered a story about the history of the creation of the N1 rocket.
The beginning of work on the N1 with a liquid-jet engine (LPRE) was preceded by research on rocket engines using nuclear energy (NRE). In accordance with a government decree of June 30, 1958, a preliminary design was developed at OKB-1, approved by S. P. Korolev on December 30, 1959.
OKB-456 (chief designer V. P. Glushko) of the State Committee for Defense Technology and OKB-670 (M. M. OKB-1 developed three versions of missiles with nuclear-powered missiles, and the third turned out to be the most interesting. It was a giant rocket with a launch weight of 2000 tons and a payload mass of up to 150 tons. The first and second stages were made in the form of packages of conical rocket blocks, which were supposed to have a large number of NK-9 liquid-propellant rocket engines with a thrust of 52 tons in the first stage. The second stage included four NRE with a total thrust of 850 tf, a specific thrust impulse in the void of up to 550 kgf / kg when using another working medium at a heating temperature of up to 3500 K.
The prospect of using liquid hydrogen in a mixture with methane as a working fluid in a nuclear rocket engine was shown in the addition to the above decree "On the possible characteristics of space rockets using hydrogen", approved by SP Korolev on September 9, 1960. However, as a result of further studies, the expediency of heavy launch vehicles with the use of liquid-propellant rocket engines at all stages on mastered fuel components with the use of hydrogen as a fuel has become clear. Nuclear energy has been postponed for the future.
Grandiose project
Government decree of June 23, 1960 "On the creation of powerful launch vehicles, satellites, spacecraft and space exploration in 1960-1967" provided for years of a new space rocket system with a launch mass of 1000-2000 tons, which ensures the launch of a heavy interplanetary spacecraft with a mass of 60-80 tons into orbit.
A number of design bureaus and scientific institutes were involved in the ambitious project. On engines - OKB-456 (V. P. Glushko), OKB-276 (N. D. Kuznetsov) and OKB-165 (AM Lyulka), on control systems - NII-885 (N. A. Pilyugin) and NII- 944 (V. I. Kuznetsov), on the ground complex - GSKB "Spetsmash" (V. P. Barmin), on the measuring complex - NII-4 MO (A. I. Sokolov), on the system for emptying tanks and regulating the ratio of fuel components - OKB-12 (A. S. Abramov), for aerodynamic research - NII-88 (Yu. A. Mozzhorin), TsAGI (V. M. Myasishchev) and NII-1 (V. Ya. Likhushin), according to the manufacturing technology - the V. M. Paton of the Academy of Sciences of the Ukrainian SSR (B. E. Paton), NITI-40 (Ya. V. Kolupaev), the Progress plant (A. Ya. Linkov), according to the technology and methods of experimental development and retrofitting of stands - NII-229 (G. M. Tabakov) and others.
The designers consistently examined multistage launch vehicles with a launch weight of 900 to 2500 tons, while assessing the technical possibilities of creating and the preparedness of the country's industry for production. Calculations have shown that most of the tasks of military and space purposes are solved by a launch vehicle with a payload of 70–100 tons, which is launched into an orbit with an altitude of 300 km.
Therefore, for the design studies of N1, a payload of 75 tons was adopted with the use of oxygen-kerosene fuel at all stages of the rocket engine. This value of the mass of the payload corresponded to the launch mass of the launch vehicle of 2200 tons, taking into account that the use of hydrogen as fuel at the upper stages will increase the mass of the payload up to 90–100 tons with the same launch weight. Studies carried out by the technological services of manufacturing plants and technological institutes of the country have shown not only the technical feasibility of creating such a launch vehicle with minimal cost and time, but also the readiness of the industry for its production.
At the same time, the possibilities of experimental and bench testing of LV units and blocks II and III stages on the existing experimental base of NII-229 with minimal modifications were determined. The LV launches were envisaged from the Baikonur cosmodrome, for which it was required to create appropriate technical and launch structures there.
Also, various layout schemes with transverse and longitudinal division of steps, with bearing and non-bearing tanks were considered. As a result, a rocket scheme was adopted with a transverse division of stages with suspended monoblock spherical fuel tanks, with multi-engine installations at I, II and III stages. The choice of the number of engines in a propulsion system is one of the fundamental problems in the creation of a launch vehicle. After the analysis, it was decided to use engines with a thrust of 150 tons.
At the I, II and III stages of the carrier, it was decided to install a system for monitoring the organizational and administrative activities of the KORD, which turned off the engine when its controlled parameters deviated from the norm. The thrust-to-weight ratio of the launch vehicle was assumed to be such that during abnormal operation of one engine at the initial section of the trajectory, the flight continued, and in the last sections of the first stage flight, it was possible to turn off a larger number of engines without prejudice to the task.
OKB-1 and other organizations carried out special studies to justify the choice of propellant components with an analysis of the feasibility of using them for the N1 launch vehicle. The analysis showed a significant decrease in the mass of the payload (at a constant launch mass) in the case of a transition to high-boiling fuel components, which is due to low values of the specific impulse of thrust and an increase in the mass of fuel tanks and pressurized gases due to the higher vapor pressure of these components. Comparison of different types of fuel showed that liquid oxygen - kerosene is much cheaper than AT + UDMH: in terms of capital investments - twice, in terms of cost - eight times.
The H1 launch vehicle consisted of three stages (blocks A, B, C), interconnected by truss-type transition compartments, and a head unit. The power circuit was a frame shell that perceives external loads, inside which fuel tanks, engines and other systems were located. The propulsion system of stage I consisted of 24 NK-15 (11D51) engines with 150 tf thrust on the ground, arranged in a ring, stage II - eight of the same engines with a high-altitude nozzle NK-15V (11D52), stage III - four NK- 19 (11D53) with a high-altitude nozzle. All engines were closed circuit.
Instruments of the control system, telemetry and other systems were located in special compartments at the appropriate stages. The LV was installed on the launching device with supporting heels along the periphery of the end of the first stage. The adopted aerodynamic layout made it possible to minimize the required control moments and to use the principle of thrust mismatch of opposite engines on the launch vehicle for pitch and roll control. Due to the impossibility of transporting entire rocket compartments by existing vehicles, their division into transportable elements has been adopted.
On the basis of the N1 LV stages, it was possible to create a unified series of rockets: N11 with the use of II, III and IV stages of the N1 LV with a starting mass of 700 tons and a payload of 20 tons in an AES orbit with an altitude of 300 km and N111 with the use of III and IV stages of the N1 LV and the II stage of the R-9A rocket with a launch mass of 200 tons and a payload of 5 tons in an AES orbit with an altitude of 300 km, which could solve a wide range of combat and space missions.
The work was carried out under the direct supervision of S. P. Korolev, who headed the Council of Chief Designers, and his first deputy V. P. Mishin. The design materials (a total of 29 volumes and 8 annexes) at the beginning of July 1962 were considered by an expert commission headed by the President of the Academy of Sciences of the USSR M. V. Keldysh. The Commission noted that the justification of the LV H1 was carried out at a high scientific and technical level, meets the requirements for the conceptual designs of the LV and interplanetary rockets, and can be used as the basis for the development of working documentation. At the same time, members of the commission M. S. Ryazansky, V. P. Barmin, A. G. Mrykin and some others spoke about the need to involve OKB-456 in the development of engines for launch vehicles, but V. P. Glushko refused.
By mutual agreement, the development of engines was entrusted to OKB-276, which did not have sufficient theoretical baggage and experience in developing liquid-propellant rocket engines with almost complete absence of experimental and bench bases for this.
Unsuccessful but fruitful trials
The Keldysh Commission indicated that the primary task of the H1 is its combat use, but in the course of further work, space became the main purpose of the superrocket, primarily an expedition to the moon and return to Earth. To a large extent, the choice of such a decision was influenced by reports of the Saturn-Apollo manned lunar program in the United States. On August 3, 1964, the government of the USSR, by its decree, consolidated this priority.
In December 1962, OKB-1 submitted to the GKOT the "Initial data and basic technical requirements for the design of the launch complex for the N1 rocket" agreed with the chief designers. On November 13, 1963, the Commission of the Supreme Council of the National Economy of the USSR, by its decision, approved an interdepartmental schedule for the development of design documentation for a complex of structures necessary for flight testing of the LV N1, excluding the construction itself and material and technical support. MI Samokhin and AN Ivannikov supervised the creation of the test site at OKB-1 under the close supervision of SP Korolev.
By the beginning of 1964, the overall backlog of work from the scheduled time was one to two years. On June 19, 1964, the government had to postpone the beginning of the LCI to 1966. Flight design tests of the N1 rocket with a simplified head unit of the LZ system (with the 7K-L1S unmanned spacecraft instead of LOK and LK) began in February 1969. By the beginning of the LKI, experimental testing of units and assemblies, bench tests of blocks B and C, tests with a prototype 1M rocket at technical and launch positions were carried out.
The first launch of the N1-LZ rocket and space complex (No. ЗЛ) from the starboard launch on February 21, 1969 ended in an accident. High-frequency oscillations occurred in the gas generator of the second engine, the pressure take-off pipe behind the turbine came off, a leak of components formed, a fire started in the tail compartment, which led to a violation of the engine control system, which issued a false command to turn off the engines for 68.7 seconds. However, the launch confirmed the correctness of the chosen dynamic scheme, the launch dynamics, the LV control processes, made it possible to obtain experimental data on the loads on the LV and its strength, the effect of acoustic loads on the rocket and the launch system, and some other data, including operational characteristics in real conditions.
The second launch of the N1-LZ complex (No. 5L) was carried out on July 3, 1969, and it also went through an emergency. According to the conclusion of the emergency commission chaired by V. P. Mishin, the most likely reason was the destruction of the oxidizer pump of the eighth engine of block A when entering the main stage.
Analysis of tests, calculations, research and experimental work lasted two years. Improving the reliability of the oxidizer pump was recognized as the main measures; improving the quality of manufacturing and assembly of THA; installation of filters in front of the engine pumps, excluding the ingress of foreign objects into it; pre-launch filling and nitrogen purging of the tail section of block A in flight and introduction of a freon fire extinguishing system; introduction of structural elements, devices and cables of systems located in the aft compartment of block A into the design of thermal protection; changing the arrangement of devices in it in order to increase their survivability; introduction of blocking of the AED command up to 50 s. flight and emergency withdrawal of the launch vehicle from the start by resetting the power supply, etc.
The third launch of the N1-LZ rocket and space system (No. 6L) was carried out on June 27, 1971 from the left launch. All 30 engines of Block A entered the mode of preliminary and main stages of thrust in accordance with the standard cyclogram and functioned normally until they were switched off by the control system for 50.1 s. continuously increased by 14.5 s. reached 145 °. Since the AED team was blocked up to 50 s, the flight was up to 50, 1 s. became practically unmanageable.
The most probable cause of the accident is the loss of roll control due to the action of previously unaccounted for disturbing moments exceeding the available control moments of the roll bodies. The revealed additional roll moment arose with all the engines running due to the powerful vortex air flow in the bottom area of the rocket, aggravated by the asymmetry of the flow around the engine parts protruding from the bottom of the rocket.
In less than a year, under the leadership of M. V. Melnikov and B. A. Sokolov, 11D121 steering engines were created to provide roll control of the rocket. They operated on oxidizing generator gas and fuel taken from the main engines.
On November 23, 1972, the fourth launch was made with the rocket No. 7L, which had undergone significant changes. The flight control was carried out by an on-board computer complex according to the commands of the gyro-stabilized platform developed by the Scientific Research Institute of the Aircraft Industry. The propulsion systems included steering engines, a fire extinguishing system, improved mechanical and thermal protection of devices and the on-board cable network. The measuring systems were supplemented with small-sized radio telemetry equipment developed by OKB MEI (chief designer A. F. Bogomolov). In total, the rocket had more than 13,000 sensors.
No. 7L flew by 106, 93 p. Without comment, but in 7 s. before the estimated time of separation of the first and second stages, there was an almost instantaneous destruction of the oxidizer pump of engine No. 4, which led to the elimination of the rocket.
The fifth launch was scheduled for the fourth quarter of 1974. By May, all design and constructive measures to ensure the survivability of the product, taking into account previous flights and additional studies, were implemented on the rocket No. 8L, and the installation of the upgraded engines began.
It seemed that the super-rocket would sooner or later fly where and how it should be. However, the appointed head of TsKBEM, transformed into NPO Energia, in May 1974, Academician V. P. Glushko with the tacit consent of the Ministry of General Machine Building (S. A. Afanasyev), the USSR Academy of Sciences (M. V. Keldysh), the Military-Industrial Commission of the Council of Ministers (L. V. Smirnov) and the CPSU Central Committee (D. F. Ustinov) stopped all work on the N1-LZ complex. In February 1976, the project was officially closed by a decree of the Central Committee of the CPSU and the USSR Council of Ministers. This decision deprived the country of heavy ships, and priority passed to the United States, which deployed the Space Shuttle project.
The total expenditures for the exploration of the Moon under the N1-LZ program by January 1973 amounted to 3.6 billion rubles, for the creation of N1 - 2.4 billion. The production reserve of missile units, almost all the equipment of the technical, launching and measuring complexes was destroyed, and the costs in the amount of six billion rubles were written off.
Although the design, production and technological developments, operating experience and ensuring the reliability of a powerful rocket system were fully used in the creation of the Energia launch vehicle and, obviously, will find wide application in subsequent projects, it should be noted that the termination of work on H1 was erroneous. The USSR voluntarily ceded the palm to the Americans, but the main thing is that many teams of design bureaus, research institutes and factories have lost the emotional charge of enthusiasm and a sense of devotion to the ideas of space exploration, which largely determine the achievement of seemingly unattainable fantastic goals.
