The E-3 Lunar probes of 1960

Sven Grahn, Sollentuna, Sweden The E-3 lunar probes launched in April 1960 represent one of the best-kept secrets of the Soviet space program. Nothing was ever published about these probes for 30 years. No rumors were flying at the time and no leaks from Western intelligence sources gave the secret away! To date very little is known about this project. No pictures of the probes have been published. Here is a compilation of information available so far: 

Origins of E-3 program

The launch attempts

In the June 1996 issue of Spaceflight (Vol. 38. No.6 p.208) Timothy Vorfolomeyev gave a detailed account of "Soviet Rocketry that Conquered Space". He gives the following information about the two E-3 launches in 1960.
E-3, 1 15 April 1960 8K72, L1-9 The third stage's (Block-E) RO-5 engine shut down prematurely or did not reach full thrust. After reaching a distance of about 200,000 km from the Earth the spacecraft fell back and burned on re-entry into the atmosphere.
E-3, 2 16 April 1960 8K72, L1-9A During ignition the engine 8D74 of strap-on booster B reached only 75 percent of thrust level. At T+0.4 sec the unit B broke away from the A core unit due to abnormal loads. The launcher fell apart during ascent. The cause lay in incomplete opening of the fine-tuning reducer's vent or in plugging of the pintle valve of the reducer's line.

Controversy about the second launch date

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