Zond L1S-1 was a Zond capsule to be placed into orbit around the Moon by the first launch of the N1, a Soviet-made super heavy-lift launch vehicle designed to land crewed Soviet spacecraft on the Moon.[1][2] The Zond capsule was equipped with a dummy lander and cameras to photograph the lunar surface for possible sites of a crewed landing.[3] The failure of the N1 launch vehicle caused the launch escape system to ignite, saving the Zond capsule from destruction.
Engines 12 and 24 shut down about 3 to 7 seconds after liftoff. The fault was found to be an error in the control system. The control system compensated by giving more power to the working engines. But at 25 seconds after lift off, the control system throttled back the working engines, as there was too much vibration. At an altitude of about 30 km, just 66 seconds after liftoff, the engines again were set to full power. This caused an oxidizer pipe to break open. A fire started, and the engine's turbopumps exploded.
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Wade, Mark. "1969.02.21 - N1 3L launch". Encyclopedia Astronautica. Mark Wade - Encyclopedia Astronautica. Archived from the original on 5 August 2014. Retrieved 5 February 2015.
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Harford, James (1997). Korolev: how one man masterminded the Soviet drive to beat America to the moon. New York; Chichester: Wiley. p. 294. ISBN9780471327219.