RD-253

From Spacefaring

Q1786759




The RD-253 and its later variants, the RD-275 and RD-275M, are liquid-propellant rocket engines developed in the Soviet Union by Energomash. The engines are used on the first stage of the Proton launch vehicle and use an oxidizer-rich staged combustion cycle to power the turbopumps. The engine burns a hypergolic mixture of unsymmetrical dimethylhydrazine (UDMH) fuel with dinitrogen tetroxide oxidizer, which are highly toxic, but storable at room temperature.