The optimal transfer system for the Ariane launcher family

Ariane 2 and 3 orbital transfer vehicle configurations were computer simulated. With the unchanged Ariane launcher and a two-burn bipropellant transfer system, higher payloads can be brought into a geostationary orbit than with a solid apogee boost or a simple apogee bipropellant boost. The payload increase possible with Az50/N2O4, depending on the Ariane type, is 15%, 8% and 7%. The percentages for LH2/LO2 are 47, 34 and 31. For the hydrogen/oxygen transfer stage a mixture ratio of 4:1 and a chamber pressure of 4 bar are needed. A tandem two tank configuration is needed because of the geometrical restrictions of the Ariane fairing. A redesigned configuration in the ARIANE 1 fairing but with a mixture ratio of 6:1 and a lower initial mass than the optimal case is shown.