|
|
 
|
|||||||||||||||||||
|
Second stage of the N1 rocket
In accordance with the Soviet nomenclature adopted during the development of multi-stage ballistic missiles, the second-stage booster of the N1 Moon rocket was designated Block B (the second letter in the Russian alphabet). Its job was to accelerate the vehicle from two kilometers per second to nearly 4.5 kilometers per second and boost it from around 47.5 kilometers in altitude to nearly 150 kilometers less than four minutes after liftoff.
Known specifications of the Block B (Stage II) of the N1 rocket:
The second stage of the N1 rocket sat on the top of the truss adapter of the first stage. The two boosters were connected together with 24 pyrotechnic locks. From bottom to top, the second stage consisted of the aft section, the eight-engine cluster, the oxidizer tank, the conical inter-tank adapter, the fuel tank and the truss adapter interfacing with the third stage. In its original configuration, Block B was equipped with eight NK-15V engines (a.k.a. 11D52), were "V" stood for the Russian word "vysotny," denoting a modification of the NK-15 engine with a longer nozzle which was optimized to operate in the vacuum of space. Otherwise, the engine was very similar to the baseline NK-15, burning liquid oxygen and kerosene. The yaw and pitch control of the stage in flight was to be provided by varying the thrust of the main engines on the opposite sides of the booster. The roll control was to be implemented with eight thrusters placed in pairs 90 degrees apart on four sides of the aft structural ring of the propulsion section, even though available imagery of the N1 rocket seems to show only four single 11D65 engines installed on the periphery of the second stage. The oxidizer tank of the second stage had a diameter of 8.4 meters and a total volume of 300 cubic meters. It was pressurized with gasified oxygen, which was produced in a special heat exchanger. The fuel tank had a diameter of 6.66 meters and a volume of 155 cubic meters. The generator gas of the engines was used to pressurize its contents. (120) According to the nominal flight program of the N1 rocket, upon the ignition of the second stage and the immediate separation of the first stage 103 seconds into the flight, the aft section of the second stage was programmed to split into three segments and separate as well with the help of small solid-propellant motors attached to the external surface of each segment. Unlike the first stage of the N1, the fully integrated Block B booster underwent extensive testing on the ground, including live firing of its combined propulsion system at the NIIKhimmash test center near Zagorsk (now Sergiev Posad), which gave confidence to developers that it would have worked had it come to that during actual launches of the N1 rocket. But because all four flights of the rocket failed during the first-stage firing, none of its upper boosters had a chance to prove themselves in flight. As early as 1967, there were proposals (INSIDER CONTENT) to replace Block B on the N1 rocket with a hydrogen- or fluorine-burning stages, but these ideas had never materialized. Block B was also proposed as the first stage of the N11 rocket variant which was never built.
|
|
|
