ETV-1

Expendable Test Vehicle 1

Mission Profile

The ETV-1 (Expendable Test Vehicle 1) was a Japanese four-stage solid-propellant suborbital test vehicle developed by ISAS in the late 1970s to validate advanced solid rocket motor components and guidance technologies planned for future Japanese orbital launch vehicles. Standing 24 m tall with a 1 m diameter and a liftoff mass of 17 tonnes, it generated 502 kN of first-stage thrust from a motor derived from the Mu family. First flown in September 1977, the ETV-1 provided valuable engineering data on propulsion, structural, and flight performance that fed directly into the development of the Mu-3S and subsequent ISAS solid orbital launch vehicles.