New upper stage for Proton, replacing Energia Corporation's Block DM, making Proton an all-Khrunichev launch vehicle. The Khrunichev-built Briz-M upper stage is a derivative of the flight-proven Briz -K stage (as used on the Rokot booster). The Briz-M consists of a central cylinder and a jettisonable external propellant tank. Propellant carried is dependent on the specific mission requirements and is varied to a minimum of 24-hours and is controlled by a closed loop, triple redundant guidance system that is commandable in flight.

High performance storable liquid engine. Engine system consists of main engine plus four 11D458 plus twelve 17D58E vernier thrusters. Propellant load 3300 kg N2O4 + 1665 kg UDMH. Main engine: Capable of 8 restarts. Total deliverable impulse 2,000,000 kgf-s. Minimum impulse 2500 kg-s. Maximum burn time 1000 seconds; minimum time 1 second. Time between burns between 15 seconds and 5 hours. Vernier engines: 4 x 40 kgf. Specific impulse 275 sec. Total summmary impulse 14,112 kg-s. Minimum impulse 4 kg-s. Orientation engines: 12 x 1.3 kgf. Specific impulse 270 sec. Minimum impulse 0.068 kg-s. Briz KM differs from Briz K in having 'compact' components, special payload truss for Globalstar dispenser. The truss is 1.8 m in diameter and has a volume of 8.8 m3.