Encyclopedia Astronautica
1972.08.21 - N1 7L State Commission


The State Commission was held to verify readiness of N1 7L for launch. Mishin was 'sick' the whole week of the hearings and had to be represented by his deputies. However neither Mishin or his first deputy Okhapkin were available - both were in the hospital. The commission nearly ruled that until Mishin was available, no launch could be approved. However the review continued.

Dry runs of the booster on the pad had already started and had already shown 17 serious problems in equipment systems and 100 problems in telemetry systems. These numbers indicated that no attempt should be made to launch 7L in its current condition. This was the first N1 with digital systems in the Block G and D stages (although there was not a complete LOK spacecraft). These had only introduced new problems, and there was no one personally responsible for making them work. Without someone being given such authority the launch schedule could not be maintained.

The first two N1's launched had amounted to only engine tests. Only on the third launch were the first stage dynamics tested. The gas dynamics problems that had led to the uncontrollable roll in that vehicle had now been solved with the assistance of TsNIIMASH and TsAGI. But why hadn't 3L also shown the roll problem? As it turned out, the shutdown of two engines at launch had prevented the problem from developing, whereas in 6L all the engines were operating correctly. The solution in 7L was the introduction of four roll-control engines. These had been developed by TsKBEM and used gas generator gases from the engines. The same design team had already successfully developed the vernier engines of the R-7, the 8D54 engine for the Block L of the Molniya 8K78 booster, and the 8D58 engine for the Block D of the N1 and Proton.

The guidance system for 7L would be essentially new, using the 'Biser' digital computer. Coupled with a three-axis guidance platform, the system would provide terminal guidance for precise orbital insertion. The system included self-test diagnostics and back-up operational modes. One computer was installed in the Block V third stage and controlled the first three stages. Another was in the LOK, and controlled the upper stages during translunar injection, lunar flyby, and return to earth. The Biser used Tropa integrated microprocessors developed by the Ministry of Electronics Industries.

The booster also features a new freon anti-fire system and a massive new telemetry capability with 13,000 separate sensors. Asbestos was used to shield the cables and electronics from heat. It was felt the KORD engine control system had now achieved a high level of reliability after five years of stand testing.

The L3, consisting for this mission of the Blocks G, D, and LOK, were being integrated at Area 2B. There were many problems with the new digital computers, which became the pacing item. Another issue were the VP53 digital-to-analogue units (42 per rocket) that translated the computer commands to the engine control systems. There was a problem with the transformers of these units.

Following these presentations, the state commission, headed by Afanasyev and Lapygin, stated their concerns. They wondered why these new computers were installed in 7L. This amounted to practically starting over again with booster development. It would have been less risky to use the old analogue systems. They noted that the replacement transformers could not be installed until the last minute, meaning they may have not been tested adequately.

The commission noted that despite the new avionics, 7L still used the old engines, which had been blamed for the previous launch failures. The new, vastly improved, Kuznetsov engines would be available in N1 8L. So why fly 7L, with a strong likelihood of another failure? Mishin's team replied that they needed to test the new guidance system, Blocks G and D, and the LOK systems. What was to be done with this rocket if they didn't fly it? Afanasyev finally agreed with this argument and went back to Moscow with the recommendation to proceed.

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