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Supposedly the Progress modules used for ISS reboost, attitude control, and debris avoidance have two large engines and some number of steering jets.

I know Zarya has 24 large and 12 small in addition to its two main engines, and the same page says that between Zarya and Zvezda there are 32 radial thrusters in two sets of 16.

I imagine Zarya, Zvezda, and Progress all have similarly sized thrusters — so it seems likely that there are three sizes on Progress. But I don't know what I'm looking for in pictures like this one.

Does anyone in here have an insight into Progress' control capability? Might it be in one of the Space Station Program interface control documents, and if so, can someone point me to the correct one?

Thanks!

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This was an interesting question to research. I did not find one definitive source, but have attempted to synthesize an answer from the list of references at the end.

There have been a number of versions of Progress with slightly different propulsion systems. AFAIK this information is correct for the latest version currently in use.

The Progress propulsion system uses as propellants nitrogen tetroxide / unsymmetrical dimethylhydrazine. The main engine and attitude control thrusters use the same propellant tankage. There are four propellant tanks and four helium pressurization tanks. Unused propellant can be transferred to the ISS in addition to propellants specifically carried as cargo.

The main engine provides axial thrust and its nominal thrust level is 2950 N. It is variously referred to as the S5.80 or KTDU-80 engine.

There are 28 attitude control thrusters, each with a thrust of 130 N. The attitude control thrusters are divided into several groupings:

  1. Two clusters of six engines each located 180 degrees apart on the forward part of the Progress service module. These thrusters have two each pointed in the forward, lateral, and tangential directions.
  2. Two clusters of two engines each located 180 degrees apart on the forward part of the service module, and 90 degrees away from the six-engine clusters. These are pointed in the lateral direction
  3. Four clusters of two engines each located 90 degrees apart on the flaring aft skirt of the service module. These are pointed radially outward.
  4. Four aft-firing engines on the aft face of the service module, located 90 degrees apart, near the perimeter. These also serve as a backup to the main engine.

enter image description here

Sources

Spaceflight 101

ISS Russian Spacecrafts (sic) [powerpoint]

Characteristics of the Soyuz attitude control system

Mir Hardware Heritage [pdf]

ISS Crew Informed of Progress Anomaly

Additions/corrections welcomed.

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  • $\begingroup$ Definitely only one main engine? That seems to conflict what I've seen about it having two. Wow, thanks for all of this information! This is outstanding. $\endgroup$ – Doctor Mohawk Apr 7 '17 at 14:39
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    $\begingroup$ I think earlier versions may have had 2, but now the aft axial thrusters serve as a backup. But I could be wrong. A lot of the sources conflict and nothing is very clear. $\endgroup$ – Organic Marble Apr 7 '17 at 14:43

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