The RD-173 engine is an improved modification of the engine RD-170 (and RD-171). The RD-173 used new materials, an advanced design of the turbopump and the injector head. The mass of the engine was reduced.
Chamber pressure and thrust could be increased. Further was worked for the increased reliability of the engine. Descendants of the RD-173 (the engine was not used in original) are the engines RD-172, RD-180 and RD-171M. While the RD-170 (and RD-171) had nozzles which swiveled on only one axis, the RD-171M and RD-180 swivels on two axes. The engine RD-172 was a variant for the Vulkan project. It is probably the pattern for the modern RD-191 and further variants.

NPO Energomash considered the possibility of construction several new variants of RD-170 family engines. The proposed variants will be marked as:

  • RD-180F   for Atlas rocket

  •  RD-181      variant for Antares rocket

  • RD-190        Methane engine

  • RD-191M   for proposed MRKS

  • RD-192      Methane engine

  •  RD-193      for prospective Soyuz rocket family

  • RD-175      for proposed STK rocket


 


 


 


RD-170


RD-180


RD-191

 



RD-151



RD-170



RD-175


           

RD-171

RD-171M

RD-171MV


                  

RD-180                                                              RD-180F (forced)      



RD-181



RD-191



RD-193