The RD-868 engine is intended for utilization in composition of LV apogee stage. It consists of the main liquid rocket engine (LRE), autonomous centralized source of propellant supply (CSP) and a system of small thrust involving thrusters.

Specific features of the engine are:
- multiple runs and thrust regulation;
- the small thrust system is fed with propellant from the main tanks;
- multifunctionality of the engine.

Consumer's characteristics of RD-868 engine

The stage flight control in pitch and yaw is effected by gimballing of the main LRE, in roll - by thtrusters operation.
The main chamber is gimballed by hydraulic actuators, the working medium of which is fuel tapped from a point downstream of the main engine's pump.
The small thrust system controls the flight in all channels when the main engine is switched-off and generates axial acceleration before the main engine startup.
The one-chamber restartable main engine of pump-fed propellant supply is designed under the gas generator scheme.
The turbine rotor's working medium is fuel-rich gas produced by the gas generator. During a startup the rotor is spinned-up by gas from the starting gas generator.
Control units are piloted by electropneumatic valves.
The engine is provided by systems of thrust regulation and mixture ratio maintenance.
The CSP ensures restartability of the main engine and small thrust system feeding with propellant from the main tanks.
A scheme of the CSP combines turbopump and expulsion concepts.