|
|
 
|
|||||||||||||||||||||||
|
First stage of the N1 rocket
In accordance with the Soviet nomenclature adopted during the development of multi-stage ballistic missiles, the first-stage booster of the N1 Moon rocket was designated Block A.
Known specifications of Block A (Stage I) of the N1 rocket:
In its original design, formulated around 1962, the first stage of the N1 was expected to carry 24 engines arranged in a circular fashion on the aft bulkhead of the stage, but by the end of 1964, the latest requirement to increase its payload from 75 to 92 tons for the goal of lunar expedition prompted the installation of an additional six-engine cluster in an inner circle around the central axis of the booster. Each of 30 engines was expected to have a thrust of 154 tons. Unusually, the steering of the rocket in flight was to be achieved through varying the thrust of individual engines on opposite sides of the vehicle rather than by swiveling of the engines. Also, in case of the failure of one individual engine, it was possible to cut off an engine on the opposite side of the rocket to maintain the symmetry of the thrust. Theoretically, the first stage of the rocket could complete its task with two pairs of engines going out of commission during the ascent. (36) Another source claimed that the booster could fly a nominal mission with three failed engines. (120) The spherical tanks of the stage were structurally suspended inside the conical walls of the booster, which carried all the structural loads of the vehicle. Due to the enormous size of the stage, its components transportable by rail were manufactured at the Progress plant in Samara, but their welding into completed tanks as well as the final assembly of the stage were performed at the Tyuratam launch site. During the flight, the fuel tank of the booster was pressurized with a gas tapped from an engine's gas generator, but before reaching the tank it would be cooled in a special mixer using fuel as a cooling fluid. (120)
The propulsion section of the Block A under assembly. The size of the stage also prevented test firing of a fully integrated booster with all its engines, leaving it to actual flights to hammer out any issues during joint operation, which proved fatal for the entire program. The first stage was also equipped with pressurized helium tanks with a diameter of two meters which were built at KB Yuzhnoe production plant in Dnepropetrovsk, Ukraine. The helium would be used in the pneumatic system of the rocket's engines. In total, the propulsion system of Block A was served by three hydraulic manifolds. The first, the pressurization manifold tapped into the liquid oxygen oxidizer supply to run it through a heat exchanger responsible for heating helium to pressurize the fuel tank. Further down the line, the oxidizer would return to the oxidizer tank via a special spray head, where it would pressurize the oxidizer tank as well. There was also a circulation manifold, which would also tap into the oxidizer supply in order to provide cooling of the engines before the liftoff. After completing its job, the oxidizer would be drained back into its respective tank. Finally, third manifold of the stage supplied propellant to the engines. Initially, the control of the stage along the roll axis was performed with the help of a dozen of steering nozzles that were installed in pairs on the aft section of the rocket. Because their thrust was deemed insufficient to prevent the failure of Vehicle No. 6L, starting with Vehicle 7L, the first stage was equipped with 12 engines, designated 11D121 and providing thrust of 1,245.7 kilonewtons, for roll control. (120) Also, starting with Vehicle No. 8L (INSIDER CONTENT), the NK-15 engines (11D51) on the first stage were to be replaced with the NK-33 variant (11D111).
|
|
|
