Upper Stages Block DM and Block DM-SL
Upper stage Block DM is intended for transferring a spacecraft
from a reference orbit to the target Earth satellite orbit
and to Earth escape trajectories for interplanetary missions,
while meeting customer requirements for attitude control
and injection accuracy.
Upper stage Block DM design is based on Block D, which was
originally developed under lunar program N1-L3 and the first
time it successfully operated in flight was as a part of
L1 complex (with Proton launch vehicle) on March 10, 1967.
Upper stage Block DM features high reliability proven by
more than 30 years of its operational history, and capacity
for multiple burns of the main engine, which allows it to
perform the required orbital maneuvers.
The design of upper stage Block DM embodies a modular principle.
The core of the upper stage is the base module, which includes
propellant tanks, engine, two propulsion units of the attitude
control/ullage system, autonomous instrumentation bay and
If the mass of spacecraft that can be delivered to orbit
needs to be increased, the autonomous instrumentation bay,
which houses the motion control system, can be removed from
the upper stage, with control over the stage transferred
to the spacecraft.
The upper stage operates on non-toxic propellant components:
liquid oxygen + kerosene.
To settle propellant when starting the main engine in zero-g
environment, a special starting-up system is used, which
includes two propulsion units operating on high-boiling
The upper stage is easy to operate.
Accuracy of SC Launches
to Geostationary Transfer Orbit and High Elliptical Orbit
Using DM Type Upper Stage For a Period Since 1996.
Upper stage Block DM was modified for the Sea
Launch (DM-SL). The modification mostly consisted in
matching interfaces between the upper stage and the payload
unit on one hand and between the upper stage and Zenit-2S
launch vehicle on the other hand.
Currently, this upper stage is used as a part of launch
vehicles Proton (launched from Baikonur launch site) and
Zenit (launched from Sea Launch system).
The mass of the fully assembled
upper stage structure, tons
Full propellant supply, tons
Main engine 11D58M thrust in vacuum,
The number of main engine firings
Mass of payload put into GEO, tons
up to 5
up to 5
Upper Stage L
The stage is designed of a propulsion compartment, a one-chamber engine 11D33 in a Cardan's suspension, and
a structural truss assembly.
Fuels tanks of stage L are covered with application specific thermal insulation for protection against solar radiation
exposure in a long-duration flight.
Special bellows allows the engine deflection up to 3° for yaw and pitch control. The roll is controlled via two nozzles
of 10 kgf thrust each capable to deflect up to 45 and operating from an extra gas generator from which gas is simultaneously
supplied to pressurize oxidizer and fuel tanks.
The engine is started in vacuum, following 1.5 hours of flight in the Earth orbit. Therefore, the stage is provided
with an attitude control and stabilization system and an ignition unit to fire the engine in vacuum.
The stage accommodates a control system for stages I and L of LV Molniya.
The stage is being currently used in LV Molniya.