RD-253 and RD-275
Type: Lower Stage Engine
Country of Origin: Russia
Manufacturer: NPO Energomash, Proton-PM
First Flight:
Status: Active
Propellant (O/F): Nitrogen Tetroxide/Unsymmetrical Dimethylhydrazine
Mixture Ratio (O/F by mass): 2.67
Cycle: Staged Combustion
Chambers: 1
Thrust (vac.): 1630 kN; 1750 kN (RD-275); 1832 kN (RD-275M)
Thrust (s.l.): 1470 kN; 1590 kN (RD-275); 1671 kN (RD-275M)
Throttle: none
ISP (vac.): 316 s
ISP (s.l.): 285 s; 287 s (RD-275); 288 (RD-275M)
Chamber Pressure: 2130 psi; 2280 psi (RD-275); 2390 psi (RD-275M)
Nozzle Ratio: 26.2
Burn time:
Ignitions: 1
Mass: 1080 kg; 1070 kg (RD-275)
Length: 3.0 m
Diameter: 1.5 m
Used in: Proton, Proton-M (as RD-275)
Links: