A semireusable launch vehicle concept as a reference system for reusability analyses

A two-stage concept called AR-X1, which uses H2O2 propellant and the HM 60 engine is presented. The first stage is reusable, the second expendable. The use of LH2/LOX in the first stage reduces the number of stages for geosynchronous transfer orbit (GTO) missions because of the higher performance. An 8 Mg payload can be injected in GTO (launch mass = 435 Mg). The first stage comprises four parallel stretched second stage tanks with 320 Mg propellants (total) and eight HM 60 engines arranged within the heat shield, plus one central HM 60 thruster for the soft landing maneuver. Engine performance is increased by adapting the expansion ratio to the external pressure. Trajectory calculations show that the first stage flight range is 1 500 km. Braking before touchdown is performed by retro thrust, requiring 2.5 to 3 Mg propellants. First-stage reuse reduces cost per launch by 50% compared with an expendable three stage design.