The MAKS (Multipurpose aerospace system) (Russian: МАКС (Многоцелевая авиационнокосмическая система)) was a Soviet airlaunched reusable launch system project that was proposed in 1988, but cancelled in 1991. An offshoot of the ENERGIABURAN program it had two RD701 rocket tripropellant engines based on RD170 engine from the first stage of ENERGIA rocket and using an Antonov An225 as a mobile launch platform