The KTDU-80 (Russian: Корректирующе-Тормозная Двигательная Установка, КТДУ) is the latest of a family of integrated propulsion system that KB KhIMMASH has implemented for the Soyuz since the Soyuz-T.

It generates 2.95 kN (660 lbf) of thrust with a chamber pressure of 880 kPa (128 psi) and a nozzle expansion of 153.8 that enables it to achieve a specific impulse of 302 s (2.96 km/s).

The integrated system without the pressurization or tanks weighs 310 kg (680 lb); it is 1.2 m (47 in) long with a diameter of 2.1 m (83 in).

It is mounted on an electro mechanically actuated gimbal that enables it to rotate ±5° in pitch and yaw.

[1] The S5.80 generates 2.95 kN (660 lbf) of thrust with a chamber pressure of 0.88 MPa (128 psi) and a nozzle expansion of 153.8 that enables it to achieve a specific impulse of 302 s (2.96 km/s).

The DPO and DO thrusters, on the other hand, were monopropellant pressure fed rockets that used catalytic decomposition of H2O2 to generate thrust.

[4] For the Soyuz-T (first flight during 1979), Isayev's OKB-2 developed for TsKBEM an integrated propulsion system, the KTDU-426.

For this version of the KTDU, they used the pressure fed cycle for all rocket engines, and consolidated propellants on the UDMH/N2O4 combination, which gives superior density and specific impulse and can be stored for years in space.

[7] Also, the switch to pressure fed cycle eliminated the use of turbopumps and its associated cost and reliability issues.

And it also enabled the reduction in minimum burn time and engine transients since there was no turbine start up and shut down hysteresis.

[8] For the new and improved high thrust RCS (DPO-B), known as the 11D428, they kept the use of 14 thrusters, but instead of H2O2 monopropellant they used the same cycle and propellant as the 11D426 SKD.

On the other hand, this change enabled the DPO-B to keep the PAO away from the reentry capsule after separation.

By Progress M-39 it flew with a full set of 11D428A-16, and finally Soyuz TM-28 marked the debut of the switch to 11D428A-16 for the crewed craft, which meant a saving of 30 kg (66 lb).

Thus, on October 23, 2002 a project was formally started to add two additional DPO-B, which brought the total number of high thrust DPO engines to 16.