The S5.142 (AKA DST-25) is a liquid pressure-fed rocket engine burning N<sub>2</sub>O<sub>4</sub>/UDMH with an O/F of 1.85. It is used for crew-rated spacecraft propulsion applications. It was used in KTDU-80 propulsion module from the Soyuz-TM to the Soyuz-TMA-M, as the low thrust thruster (DPO-M). As of the Soyuz MS, KTDU-80 does not use DPO-M anymore.
The S5.142 generates of thrust with a chamber pressure of and a nozzle expansion of 45 that enables it to achieve a specific impulse of . It is rated for 300,000 starts with a total firing time of 25,000 seconds and can do single burns from 0.03 seconds to 4,000 seconds. Each unit weights .
This engine has been used in crewed Russian space program since the Soyuz TM-23. There are two versions: