Rocket-Space Complex N1-L3 being
transported to the launch site
Rocket-Space Complex N1-L3
at the launch pad
Rocket-Space Complex N1-L3
being installed on the paunch pad
Pre-launch processing of Rocket-Space
Complex N1-L3 at the launch pad
Two rockets N1 at the launch site
Rocket-Space Complex N1-L3 in flight
The first launch of complex N1-L3 carried out on February
21, 1969 was accidental. As a result of high-frequency vibrations
in the engine ¹2 gas generator, a pressure reducing connector
behind a turbine broke off and leakage of components occurred
that caused a fire in the aft compartment and violated the
engine control system operation that commanded to shut down
engines at 68.7s.
Despite the accident, this launch has proved the validity
of the dynamic profile, launch dynamics, LV control processes
using the engine thrust misalignment and permitted to obtain
test data on LV loads, strength, the LV and launch system
exposure of acoustic loads, and other data including operating
conditions in real environment.
The second launch of complex N1-L3 carried out on July 3,
1969 and was also accidental because of faulty operation
of engine ¹8 of stage A. A certain cause of the accident
was not established. The Accident Committee headed by V.
P. Mishin concluded that the most probable cause of the
accident was a destruction of the engine oxidizer pump at
a transition to the full thrust.
Two years required to analyze the test results, perform
studies, and experiments. As a result, proper measures were
taken that allowed to exclude all expected causes of the
accidents, enhance reliability of engines, other systems
and equipment, as well as to secure the launch pad. The
primary measures were: the oxidizer pump reliability enhancement;
installation of filters in front of the engine pumps to
avoid ingress of foreign matters; pre-launch filling and
in-flight purging of the stage A aft compartment with nitrogen;
introduction of a freon fire extinguishing system; adding
of thermal protection for the structure elements, instruments,
and cables of systems accommodated in the stage A aft compartment;
introduction of engine ignition command inhibition till
50s of flight and the LV emergency escape from the launch
site at power disconnection, etc.
The third launch of complex N1-L3 took place on June 27,
1971. All 30 engines of stage A were switched to the preliminary
and full thrust modes as consistent with a nominal timeline
and were normally operating till their switchdown was commanded
from the control system at 50.1s. However, from the beginning
of flight, anomalous roll stabilization was observed and
a spin angle misalignment was increasing and by 14.s achieved
145°.n As far as the engine emergency shutdown command was
inhibited till 50s, the flight was actually not controlled
till 50.1s. The most probable cause of the accident was
an effect of not previously considered disturbances exceeding
the roll control moments. For the rocket roll control, in
less that a year, steering verniers were designed that used
producer oxidizing gas and fuel taken from main engines.
On November 23, 1972 the fourth launch of complex N1-L3
was carried out. The rocket employed for this launch was
considerably modified to eliminate the revealed drawbacks
and increase the payload mass. The flight was controlled
by the onboard Data Management System on commands from gyrostabilized
platform (A Chief Designer: N. A. Pilyugin). The propulsion
units included steering verniers. A fire extinguishing system
was introduced. Mechanical and thermal protection of instrumentation
and cable system was improved, etc. The measuring systems
were outfitted with a newly developed small-size radio and
telemetry equipment (a Chief Designer: A. F. Bogomolov).
In total, beyond 13 000 sensors were provided on the rocket.
The rocket has flied for 106.93s without comments, but 7s
before the designed separation of stages I and II, an actually
instantaneous breakdown of the engine ¹4 oxidizer pump occurred
that caused the rocket destruction.
The next launch was scheduled for the fourth quarter of
1974. By May, relying on the analysis of previous flights
and further studies, all design and measures focused on
the rocket survivability. Assembly of modified reusable
engines began. However, the Academician V. P. Glushko, appointed
to be the Director General of NPO Energia in May 1974, by
his order and a silent consent of the Ministry of Machinery,
terminated all activities associated with complex N1-L3.
In total, by January 1973, expenses for the N1-L3 program
reached 3.6 milliards of rubles of which the N1 development
cost was 2.4 milliards of rubles ( at that time rate).
The Decree of the Central Committee of CPSU enacting to
terminate work on complex N1-L3 and write the costs into
losses was released only in February 1976. Thereupon, all
rocket stages, pre-launch processing and measuring equipment
were destroyed. Herewith, costs in amount of 6 milliards
of rubles (at the 1970s rate) spent on the program were
written into losses.
Although the experience gained in designing and manufacturing,
operating and ensuring reliability of the powerful rocket
system N1 has been employed in full measure in developing
LV Energia and is likely
to find wide application in future projects, it is impossible
not to admit that cutting down of work on N1 was a mistake.
Later on, to develop a rocket of a similar capacity required
13 years more and 14.5 milliards of rubles.