Soviet N1 project overview.
Historical information on the N1.
The N1 rocket team.
Design information on the N1 model.
The launch of the N1 at LDRS XX.
More information on the Soviet space program.
Text and pictures from
Rockets of the World.
In 1960, Sergei Korolev proposed a giant booster capable of launching, 40
to 50 metric tons (88,00 to 110,000 lb) into low Earth orbit. This
projected rocket, with ten times the payload capacity of the existing
Vostok booster, was called the N1. V. P. Glushko, the Soviet Union's
premier rocket propulsion expert, felt that it would be prohibitively
expensive to build immense oxygen-hydrogen engines like the F-1's that
would power the American Saturn V. Instead, he proposed large engines
burning unsymmetrical dimethyl hydrazine (UMDH) and nitrogen tetroxide
(N204). These propellants. used in the American Titan,
are storable and ignite on contact. But they are less efficient than liquid
oxygen and kerosene, and are highly toxic. Korolev instead chose to power
the lower stages of his super booster with liquid oxygen and
kerosene. Glushko took his technology to the Chelomei design bureau, which
selected his engines to power the UR500 Proton booster. Korolev turned to
the design bureau of Nikolai Kuznctsov (NK) for the Ni's engines.
In its original form, the first stage of the N1 was to be propelled by a
ring of 24 engines. Air would be vented into the space inside the ring,
where external combustion of exhaust gasses was supposed to augment the
Like the American Saturn, this super-rocket had no specific mission at
first. Development of the N1 began in 1961, the year of US President
Kennedy's commitment to place an American on the Moon by the end of the
decade. But the N1 was not chosen to carry a Soviet citizen to the moon.
That job was assigned to the Proton, which would only make a circumlunar flight.
It was not until 1964 that the Soviet Union made a secret decision to use
the N1 to land a man on the Moon before the Americans. Through the
mid-60's, as the lunar landing mission evolved, the N1 grew through a
series of re-designs, eventually doubling its low Earth orbit capacity to
98 metric tons (109 US tons). The central air vents were replaced by six
additional engines. By the beginning of 1967, the N1 booster's design was
nearly done, as was the design of the L3 lunar spacecraft. By November, a
mock-up was on the pad.
The N1 stood 105 meters (344 ft) tall and weighed 2788 metric tons (6.1
million lb) fully fueled. This compares with 110.7 meters (363 it) and 2913
metric tons (6.4 million lb) for the American Saturn V. The first three
stages of the N1, blocks A. B, and V. each took the form of a truncated
cone containing a spherical kerosene tank above a larger liquid oxygen
(LOX) tank. The first stage, Block A, was powered by 30 NK-33 engines,
together producing 4620 metric tons (10 million lb) of thrust. This far
exceeded the 3469 metric ton (7.65 million lb) thrust of the American
Saturn V Moon rocket. The N1's "KORD" (Russian acronym for control of the
work of the engines) system steered the rocket in pitch and yaw by
throttling the 24 fixed outer engines. Roll control was maintained by
routing engine turbine exhaust through six swivelled nozzles. Arrayed
around the base of the N1's first stage were four grating stabilizers, each
consisting of a cross hatched array of metal strips (acting as fins) held
in a horizontal frame After a first stage burn of 110 seconds. the second
stage was to ignite its eight NK-43 engines for a 130-second burn. Finally,
the third stage would insert the L-3 complex into orbit with a 400-second
burn of its Four NK-31 engines.
The L3 spacecraft complex was concealed in a shroud topped by emergency
escape rockets. During the second stage burn, the shroud would be
jettisoned. revealing the four principal units of the L3 system. The
kerosene-LOX Block G rocket served as the fourth stage of the N1, and was
to send the craft on its translunar trajectory. The Block D fifth stage,
also burning kerosene and LOX, served multiple functions. First, it would
provide course corrections on the way to the moon, It would slow the L3
spacecraft to enter lunar orbit. Finally, it was to slow the lunar module
(Block E) to drop it from lunar orbit down to an altitude of about a
kilometer (0.6 mi). The lunar lander itself' was a small spherical craft
with four landing legs and a single rocket engine burning
N2O4 and UMDH. The final section of' the 1.3
spacecraft was the Block I lunar orbiter, a Soyuz spacecraft with an
enlarged service module powered by an engine burning
N204 and UMDH to return the cosmonauts to earth.
According to the L3 flight plan, once the Block D stage slowed the craft
into lunar orbit, one cosmonaut would transfer to the lander by space
walk. No pressurized tunnel was provided between craft. The lunar lander
and attached block D stage would separate from the Soyuz for the descent
to the Moon. About a kilometer (0.6 on) above the surface the block D was
to separate from the lunar lander, which would descend the final distance
under its own power.
The single cosmonaut on the lunar surface would carry out a program similar
to that of Apollo 11, planting a Soviet flag, leaving a number of
experiments, and picking up rock and soil samples. The spacecraft could
support the cosmonaut on the moon for a couple days, although a Moon walk
could last no more than an hour and a half. Once the lunar exploration was
complete, the cosmonaut was to ride to lunar orbit under the power of the
lander's single engine. The Block E module would leave only its landing
The lunar lander and extended Soyuz would dock in orbit, and the landing
cosmonaut would transfer himself and his samples by space walk. After
discarding the lander, the Block I lunar Soyuz would fire its engine for a
return to Earth.
The Moon landing project was an expensive and time-consuming venture. To
hasten the completion of the project, and to keep costs down, the complete
first stage of the N1 was never static tested on the ground. As a result,
the Soviets managed to load the first N1 booster onto its pad at Baykonur
on May 7, 1968, only four years after approval of the Moon landing
program. But the Soviets were failing behind the Americans, who had already
launched two unmanned Saturn V boosters. The Soviets would not catch up
quickly, as cracks were found in the first stage structure. The booster was
rolled back to the hangar for repairs. The N1 would not fly until the next
It was a clear day at the Baykonur Cosmodrome when the thirty engines at
the base of the first N1, unmanned flight 3L, came to life at 12:18 PM on
February 21, 1969. Even before liftoff, there was a minor malfunction. A
safety feature of KORD steering system was the ability to maintain thrust
symmetry by shutting off an engine directly opposite any that
malfunctioned. But KORD itself malfunctioned, shutting off a pair of
healthy engines. In spite of the malfunction, a ring of explosive bolts
detonated at the base of the rocket, allowing it to lift off. Powered by 28
of 30 engines, the N1 still rose faster than the American Saturn that had
sent the three Apollo 8 astronauts around the Moon two months before. N1-L3
could still fly by the Moon with two engines out, as a longer burn by the
remaining engines would compensate for the loss of thrust.
But the erroneous KORD cutoff triggered a fire in one of the shut down
engines. Within a minute, the fire spread to the cabling and propellant
lines for other engines. The KORD system shut down the entire first stage,
and triggered the firing of emergency escape rockets that carried the L3S
(unmanned L3) payload away from the booster as if it had been manned. The
booster followed its suborbital trajectory to a point 45 km (30 mi) from
the pad and crashed into the ground.
At 11:18 PM Moscow time on July 3, 1969, less than a month before the
flight of Apollo 11, the second N1, flight 5L, lit up Baykonur with the
flames of its 30 engines. But less than a quarter second before liftoff, a
bit of metal from a pressure fluctuation sensor made its way into a pump,
triggering an explosion in one engine. In the half-second after launch,
KORD shut down four engines. The remaining 26 engines struggled 200 meters
(600 ft) above the pad as the tail section blew to pieces. Within ten
seconds of launch, all engines were commanded to stop, yet one continued to
burn. The remaining engine merely spun the rocket about its axis as it
collapsed back onto the pad. The explosive impact destroyed the N1 the pad,
and ground support equipment, as well as damaging a neighboring pad and a
second N1 booster. Only the unmanned L3S spacecraft survived, carried to
safety by its escape rocket. The N1 would not fly again for 2 years.
On June 27, 1971, a third N1 flight 6L, lifted off from Baykonur. This
vehicle reached an altitude of 250 meters (800 ft) before a control failure
set the rocket rolling about its axis. The spin caused the rocket to twist
apart between the second and third stages. The upper stages toppled and
exploded while the first two stages shot past, out of control. The lower
stages crashed 30 km (20 mi) away, blasting a crater 30 meters (100 ft)
wide and 15 meters (50 ft) deep.
N1 flight 7L featured an improved first stage. The tail skirt was trimmed
down and the fuel line fairings streamlined to reduce air resistance. On
November 23, 1972, N1-7L lifted off, bearing the final L3S craft. This
time, the N1 performed flawlessly-for 107 seconds. Then unexpected
vibrations began, and before staging, the mighty booster fell to pieces and
Two more N1's were assembled for flights in 1974 and 1976. But in 1974,
propulsion expert V. P. Glushko took over the Korolev design bureau from
V. P. Mishin (who had taken over upon Korolev's death in 1966). Glushko had
not liked the N1 program since Korolev had rejected his innovative choice
of propellants. Glushko canceled the N1, renamed the organization
Energiya, and set out to build a large rocket using high-energy
The remaining N1's were dismantled, their engines put into storage, and
their airframes scrapped or adapted into storage sheds. The L3 hardware
that wasn't scrapped was placed in closed museums for aerospace engineers
only. And for 15 years, the Soviets continued to pretend the project never
existed. Only in 1989 did the Soviet Union acknowledge the existence of the
The story of the N1 is not over. In the post-Soviet era, several western
aerospace companies have considered using N1 engines in various
internationally-developed space boosters. In the United States, Aerojet
has purchased two examples of the NK-33 engine for static tests. Aerojet is
considering manufacturing these engines under license to power new versions
of the American Atlas and Titan.
The first N1 booster, 3L, moments before ignition.
|Stage 1 (Block A):|| |
|Loaded Weight||1,870,000 Kg (4,110,000 lb)|
|Thrust||45,300,000 N (10,200,000 lb)|
|Impulse||4,980,000,000 N-sec (1,120,000,000 lb-sec)|
|NAR designation||30 x AA 1,510,000|
|Stage 2 (Block B):|| |
|Loaded Weight||540,000 Kb (1,200,000 lb)|
|Thrust||14,000,000 N (3,150,000 lb)|
|Impulse||1,820,000,000 N-sec (410,000,000 lb-sec)|
|NAR designation||8 x AB 1,750,000|
|Stage 3 (Block V):|| |
|Loaded Weight||185,000 Kb (407,000 lb)|
|Thrust||1,610,000 N (362,000 lb)|
|Impulse||642,000,000 N-sec (144,000,000 lb-sec)|
|NAR designation||4 x AA 400,000|
|Stage 4 (Block G):|| |
|Thrust||400,000 N (90,000 lb)|
|Stage 5 (Block D):|| |
|Thrust||85,000 N (19,000 lb)|
If you don't have a copy of Peter Alway's wonderful Rockets of the World,
you definitely need one.
Material like this, and even more, exists for most rockets built and provides
a treasure trove of information for modelers and those interested in space.
They can be purchased directly through the publisher,
or at larger bookstores.