S5.142

S5.142
Country of originRussia
Date1990-1996
First flight1996-02-21 (Soyuz TM-23)
DesignerKB KhIMMASH
Applicationattitude control thruster
Predecessor11D427M
StatusRetired
Liquid-fuel engine
PropellantN2O4 / UDMH
Mixture ratio1.85
Cyclepressure fed
Configuration
Chamber1
Nozzle ratio45
Performance
Thrust, vacuum25 N (5.6 lbf)
Chamber pressure0.88 MPa (128 psi)
Specific impulse, vacuum285 s (2.79 km/s)
Burn time25,000 seconds
Restarts300,000
Dimensions
Length180 mm (7.1 in)
Diameter136 mm (5.4 in)
Dry mass0.9 kg (2.0 lb)
Used in
KTDU-80
References
References

The S5.142 (AKA DST-25) is a liquid pressure-fed rocket engine burning N2O4/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 25 N (5.6 lbf) of thrust with a chamber pressure of 0.88 MPa (128 psi) and a nozzle expansion of 45 that enables it to achieve a specific impulse of 285 s (2.79 km/s). 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 0.9 kg (2.0 lb).