The L3 system
was a combination of rocket stages and spacecraft designed
to land a single Soviet cosmonaut on the surface of the Moon, after its delivery into low-Earth orbit by a three-stage N1
rocket with a projected payload mass of around 95 tons.
During a nominal ascent to the initial Earth orbit, the Emergency Escape System and the payload fairing would separate and fall back to the ground. A 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 piloted spacecraft on the surface of the
Moon during a 11-12-day expedition which included the following steps:
The N1
rocket delivers the L3 system into the low-Earth orbit, where it can
remain up to one day;
Block
G accelerates the L3 system to Earth-escape velocity, sending the L3
system toward the Moon;
Block
G separates;
Block
D completes the acceleration and conducts two trajectory corrections
during a 3.5-day flight between the Earth and the Moon;
Block
D provides a braking maneuver, inserting the L3 system into lunar orbit,
where it can remain up to four days;
Two Block
D engine firings transfer the L3 system from a circular to a 100 by 20-kilometer
pre-landing orbit around the Moon;
One cosmonaut
transfers from the LOK spacecraft to the LK lander, during an EVA:
A combination
of Block D and the LK spacecraft separates from the LOK spacecraft on the sixth day of the mission:
A Block
D engine firing transfers the LK lander on a descent trajectory toward
the lunar surface;
Block
D separates from the LK lander;
Block
E engine firings aboard the LK lander provides for a soft-landing on
the Moon surface;
A cosmonaut
conducts an EVA, during a stay on the lunar surface lasting from 6 to
24 hours;
A Block
E engine firing provides for the liftoff of the LK ascent stage from
the lunar surface and reaching lunar orbit;
Block
I (INSIDER CONTENT) aboard the LOK spacecraft provides escape velocity, sending the LOK
toward Earth;
Block
I onboard the LOK spacecraft provides trajectory corrections during
a 3.5-day flight toward the Earth;
A reentry
capsule of the LOK spacecraft separates from the habitation module and
the instrument section, then it reenters the Earth atmosphere and lands.
Development of the L3 complex
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 Feb. 10, 1965, the plan for the development of the L3 system was
officially approved. (52) In the following years, its development was marred by a severe mass deficit, which evidently was not fully resolved until the cancellation of the entire N1-L3 project in 1974, after four failed launches of the N1 rocket with various prototypes of the L3 complex, none of which represented a fully configured vehicles certified to carry the crew.
A full-scale prototype of the L3 expeditionary complex with a mockup version of the L1-based crew vehicle during assembly in Tyuratam. Credit: RKK Energia
