rocket, RD-181 in American Orbital ATK Antares rocket, and the proposed RD-193 for the Soyuz-2-1v project. Proposed variants On 28 July 2011, NPO Energomash summarised the results of the work on Rus-M rocket engine and considered the possibility of construction several new variants of RD-170 family engines. According to the information, new and proposed variants will be marked as: RD-180M for crewed Atlas V rocket (Not required, current RD-180 meets crewed Atlas V requirements.) RD-180V for Rus-M rocket. RD-175 with 9800 kN thrust for proposed Energia-K rocket. In 2017, Director General of RKK Energia Vladimir Solntsev referred to a "simplified" and "cheaper" version of the RD-171 engine in connection with the Soyuz-5 (Sunkar) project. Specifications 4 combustion chambers, 4 nozzles 1 set of turbines and pumps; turbine produces approximately 257,000 hp (192MW); equivalent to the power output of 3 nuclear-powered icebreakers Ignition: pyrophoric start-up fuel capsule (triethylaluminium) Vacuum thrust: Vacuum Isp: Sea-level Isp: Weight: Thrust-to-weight ratio: 82 See also Comparison of orbital rocket engines References External links Manufacturer's Page (Archived) RD-170/171 specifications and design (in Russian) External image Astronautix.com entry on RD-170 Rocket engines of the Soviet Union Rocket engines of Russia Rocket engines using kerosene propellant Soviet inventions Rocket engines using the staged combustion cycle Energomash rocket engines