The MAKS Spaceplane: Multipurpose aerospace system (Russian: МАКС)

The MAKS (Multipurpose aerospace system) (Russian: МАКС (Многоцелевая авиационно-космическая система)) was a Soviet air-launched reusable launch system project that was proposed in 1988, but cancelled in 1991. An offshoot of the ENERGIA-BURAN program it had two RD-701 rocket tri-propellant engines based on RD-170 engine from the first stage of ENERGIA rocket and using an Antonov An-225 as a mobile launch platform