The L3 system was a four-element combination of rocket stages and spacecraft designed to land a Soviet cosmonaut on the surface of the Moon, after the L3's delivery into low-Earth orbit by the three-stage N1 rocket.
The L3 spacecraft under payload fairing minus the emergency escape system during its final assembly in Tyuratam.
The L3 system included:
The total weight of the L3 system in a 290-kilometer circular Earth orbit was to be around 70 tons. (111)
L3 flight profile
The N1-L3 system was expected to deliver a manned spacecraft on the surface of the Moon during a 11-12-day expedition, which included the following steps:
Basic configuration of the L3 complex, which included the LOK spacecraft was formulated by 1963, or roughly two years after a similar architecture of the lunar expeditionary spacecraft had been adopted in the United States.
Before August 1964, it was already clear that the N1-L3 would not be able to support three people during the lunar expedition, therefore the crew of the complex was reduced to two cosmonauts with only one of them actually landing on the lunar surface onboard the lunar module, LK, while the second would remain in lunar orbit onboard LOK. (78)
In December 1964, Korolev's team completed a preliminary design of the N1-L3 complex. It envisioned the launch of a two-man spacecraft by a single N1 rocket and the landing of one cosmonaut on the surface of the Moon. (36,52) The expert commission led by Mstislav Keldysh evaluated the project, and on February 10, 1965, the plan for the development of the L3 system was officially approved. (52)
Fairing deployment tests for the L3 spacecraft.
Block G fires, sending the L3 complex toward the Moon. Click to enlarge. Copyright © 2002 Anatoly Zak
The propulsion section of the LOK spacecraft with Block D on the background. Copyright © 2000 by Anatoly Zak