The 11D428A-16 (manufacturer's name RDMT-135M) is a liquidpressure-fedrocket engine burning N2O4/UDMH with an O/F of 1.85. It is used for crew-rated spacecraft propulsion applications. It is currently used in the KTDU-80 spacecraft propulsion module. The previous version, the 11D428A (manufacturer's name RDMT-135) is still used as the reaction control system thrusters of the ZvezdaISS module.
The 11D428A-16 generates 129.16N (29.04lbf) of thrust with a chamber pressure of 0.88MPa (128psi) and achieves a specific impulse of 291s (2.85km/s). It is rated for 500,000 starts with a certified ignition time of 0.03 seconds to 2000 seconds. Each unit weights 1.5kg (3.3lb).