Under the Future European Space Transportation Investigation Programme (FESTIP) of 1994-1999 French agencies and contractors designed a number of alternative reusable space launchers. This one was a Horizontal Takeoff / Horizontal Landing Two Stage to Orbit proposal with Mach 4 stage separation. Vehicle consisted of an unpowered 'reusable winged drop tank' and 2-engine expendable Ariane-5 upper stage.