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Space


G-1e / N-1 / 11A52 - Flights

All four launches of the N-1 launch vehicle ended in accidents, and, ultimately, projects that were somehow connected with this launch vehicle were shut down altogether.

  1. The first launch of the N1-L3 missile and space complex on February 21, 1969 ended abnormally. The telemetry specialists provided unequivocal information: all of the engine shutdowns were prompted by KORD system commands. The culpability of the KORD system in shutting down engine #12 with a false command was proven unequivocally. As a result of the high-frequency oscillations that occurred in the gas generator of the engine No. 2, the pressure-tapping connection behind the turbine came off and a leak of components resulted in a fire in the tail section. A cloud of fuel mixture formed and burst into flame 55 seconds into the flight. The fire engulfed a large portion of the aft section of Block A. Sixty-eight seconds into the flight, the flame that was raging in the aft section burned through the insulation of the cable network. The engine monitoring system issued a command to turn off the engines at 68.7 seconds. What happened was not a random occurrence, but the logical result of economizing on the development of a stand for ground testing. Despite the accident, this startup confirmed the correctness of the selected dynamic scheme, launch dynamics, LV control processes by means of engine thrust misalignment, allowed to obtain experimental data on LV loadings and its strength, acoustic load on rocket and launch system and some other data in including performance characteristics in real conditions.
  2. The second launch of the N1-L3 complex was carried out on July 3, 1969 and also ended abnormally due to the abnormal operation of the engine No. 8 of Block A. Unequivocally, the cause of the accident was not established. According to the conclusion of the emergency commission under the chairmanship of V.P. Mishina the most likely cause of the accident was the destruction of the oxidizer pump when it came to the main stage. Two years were spent on analyzing test results, additional calculations, research and experimental work. As a result, measures were taken to eliminate all the alleged causes of accidents, improve the reliability of engines, other systems and units, and also to secure the launch facility. The main measures were to increase the reliability of the oxidizer pump; installation of filters before the engine pumps to prevent foreign objects from entering it; filling before the start and purging with nitrogen of the tail section of block A in flight and introducing a freon fire extinguishing system; the introduction of thermal protection of structural elements, devices and cables of systems located in the tail section of Block A; the introduction of an emergency engine shutdown command (AVD) blocking up to 50 from the flight and an emergency launch of the launch vehicle to reset the power supply, etc.
  3. The third launch of the N1-L3 rocket-space system was carried out on June 27, 1971. All 30 engines of the block A went to the mode of the preliminary and main stages of the thrust in accordance with the regular cyclogram and functioned normally before they were turned off by the control system by 50.1 s, however, from the beginning of the flight, there was an abnormal course of the roll stabilization process, and the rotation angle mismatch It increased continuously and reached 145 C by 14.5 sec. Since the emergency shutdown command was blocked for up to 50 seconds, the flight to 50.1 seconds was almost uncontrollable. The most probable cause of the accident is the action of unaccounted disturbances, which exceed the available control moments by roll. To ensure the control of the rocket by roll, in less than a year, steering engines were created that operate on oxidizing generating gas and fuel, taken from the main engines.
  4. On November 23, 1972, the fourth launch of the H1-L3 complex was carried out. The missile that started in this launch has undergone significant changes aimed at eliminating the identified shortcomings and increasing the mass of the payload that is being withdrawn. Flight control was carried out on-board computer system on the commands of gyrostabilized platform (chief designer NA Pilyugin). The composition of propulsion systems introduced steering engines, fire extinguishing system, improved mechanical and thermal protection devices and on-board cable network, etc. Measuring systems were completed with newly created small-size radiotelemetric equipment (chief designer AF Bogomolov). In total, over 13,000 sensors were installed on this rocket. The rocket flew without remarks 106.93 s, but for 7 seconds before the estimated time of separation of the first and second stages, an almost instantaneous destruction of the oxidizer pump No. 4 occurred, which led to the elimination of the missile.
  5. The fifth launch of the N-1-L3 N 8L complex was was scheduled for the fourth quarter of 1974. However, the fifth launch did not take place, since in December 1972 the US completed its lunar program with the flight of the Apollo 17 spacecraft and the political interest in the lunar program disappeared. By May 1974, all the design and engineering activities to ensure the survivability of the rocket, resulting from the analysis of previous flights and additional research, were implemented on the rocket. Installation of modernized reusable engines began. However, the academician V.P. Glushko, appointed in May 1974 as the head of NPO Energia, with the tacit consent of the Ministry of General Mechanical Engineering, stopped all work on the H1-L3 complex.

Two already produced copies of the N1F carriers were destroyed, and 150 manufactured NK-33 and NK-43 engines (high-altitude analogue NK-33) in KB Kuznetsov were kept until the end of the XXth century, when some of them, as well as a license for production, were sold to the American company "Aerojet". Total costs for the H1-L3 program amounted to 3.6 billion rubles by January 1973, of which 2.4 billion rubles were allocated to create the H1. (in the prices of those years).

The resolution of the Central Committee of the CPSU and the USSR Council of Ministers on the termination of work on the complex and write-off of costs came only in February 1976. After that, the production reserve of missile blocks, virtually all the equipment of the technical, launching and measuring systems was destroyed. At the same time, expenses in the amount of 6 billion rubles were written off. (in the prices of the 1970s), spent on the topic.




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Page last modified: 09-07-2018 13:24:34 ZULU