The AVUM (Attitude & Vernier Upper Module) has a bipropellant main propulsion system to provide orbital injection, and a monopropellant propulsion system for roll and attitude control.
It is designed to inject different payloads into different orbits, and ensures the fine pointing of satellites prior to separation. At the end of the mission, it is deorbited under safe conditions to limit the amount of orbital debris.
The AVUM contains about 577 kg. of liquid propellant (UDMH/NTO), distributed in four tanks. It is powered by an engine derived from the re-ignitable RD-869, providing 2.45 kN of thrust. It contains also 38.6 kg. of hydrazine to supply two sets of three monopropellant thrusters to control roll and attitude.