On the day of the launch the assembly building and worker's villages at Areas 112 and 113 were completely evacuated on the principle that 'God helps them what helps themselves'. The launch directors at the Sixth Control Centre were: Colonel Pavel Katayev, Yevgeniy Moiseyev, Launch Complex commander Colonel Anatoliy Kirillov, N1 Chief Designer Boris Dorofeyev, Afanasyev, and Mishin.
The payload was the 7K-L1A adaptation of the 7K-L1 spacecraft. This had a modified engine block and a total mass of 6900 kg. The planned mission was a lunar orbital flight. The L3 assembly would have been placed into a 204 x 287 km orbit of the earth at 597 seconds after lift-off. Total mass in earth orbit would have been 70.56 tonnes (the Block G, Block D, and 7K-L1A). The launch window for the lunar launch was open from 18 to 21 February; the launch was made on the last possible day. The N1 had a total mass of 2762 tonnes at ignition and 2756 tonnes at lift-off. Lift-off thrust was measured at 4,590 tonnes. The propellants had been densified before loading by chilling the Lox to -191 deg C and the fuel to -15 deg C. The mission plan called for the Block G to put the Block D and 7K-L1A on a translunar trajectory. After a 3.5 day coast to the moon, the Block D would fire and place the assembly into lunar orbit. After two days of photography of the lunar surface, the Block D would fire again and place the 7K-L1A on a trans-earth trajectory. The Block D would separate and the 7K-L1A would use its own engines for mid-course corrections on the return leg. After re-entry in the atmosphere, the 7K-L1A would be recovered on Soviet territory.
Launch came at 12:18:07 local time. The heat of the exhaust vaporised the top few meters of the launch pad's concrete. The booster rose into the sky on a pillar of flame 3 to 4 times longer than its own 110 m height. However telemetry later revealed the vehicle had run into trouble immediately at lift-off. As a result of a rising high frequency oscillation in the gas generator of engine number two, some engine components tore off their mounts, resulting in a forced leak of propellants, setting in motion a fire in the tail compartment. The BKS engine monitoring system detected the fire, but then gave an incorrect signal, shutting down all engines at 68.7 seconds into the flight. The vehicle was destroyed by range safety 70 seconds into the flight. The escape tower worked as designed. The remains of the N1 crashed 52 km downrange from the pad.
In the control room gloom prevailed. 'Everything has ended' - 'All those years of work down the drain..' Only Barmin was upbeat - 'don't worry, my launch complex is note damaged'. Barmin had said the same thing on the first R-7 launch on 15 May 1957. But that first ICBM had run for 100 seconds, which was an enormous accomplishment at that time, but nothing today. There was much more at stake. Five years of enormous and costly effort may have died with the booster.
The preliminary investigation into the cause of the failure took several days, but Mishin was impatient to know the cause. Preliminary word was that the problem was a turbogenerator, but it took until March for a more complete analysis to be available. A turbogenerator had leaked hot 340 deg C gas. This had started a fire in the compartment. The KORD engine control system was affected, and a 1000 Hz vibration of the booster, in harmony with the operating frequency of the system, stimulated an erroneous shut-down command to all engines. The operating voltage of the system had increased to 25 V instead of the 15 V design voltage. The solution implemented for the next booster was to reroute the KORD sensor and command lines, and to insulate them with asbestos. However the leadership still refused to pay for a test stand at Tyuratam to ground-test the Block A first stage! The project budget just couldn't accommodate the expense...
After the 3L failure everyone knew there was no chance at all of beating the Americans to the moon. The revised programme included further unmanned L1 flights, automated return of lunar soil by Babakin's robot landers, a crash programme of Soyuz 7K-OK earth orbit manned flights, and development of new versions of the Soyuz for military space programmes. 5L was scheduled for the next test launch. Booster 4L had always been seen as a back-up booster for the failed 3L, and there was no manpower available to complete it.
At 41 seconds after launch, one of the 32 engines of the N1 first stage shuts down, followed by all of the others. The KORD should have only shut down one engine opposite the failing engine -- and the launch vehicle could still continue with the loss of six engines. The booster reached its peak altitude of 27 km at 50 seconds into the flight, then continued to impact 23 km down range. The L1 spacecraft capsule was pulled away by the SAS escape tower, and landed under its parachute successfully. Kamanin observes that the Soviet lunar program is depending on the success of the N1, but a series of UR-500K launches could be used as well to assemble the lunar spacecraft in low earth orbit. In his opinion the N1 may one day fly, but it can never be a reliable booster due to the inherent design flaws.