Orbital Propulsion Module (OPM). Study on Coni-Spherical Surface Tension Tanks (Costa)

摘要

The technical feasibility of an Orbital Propulsion Module (OPM) comprising coni-spherical surface tension tanks, attached to a heavy satellite (Spacebus 400, mass in GEO = 1600 kg BoM) for launch by Ariane 44L was investigated. The OPM (having a bipropellant mass capability of nominal 2900 kg) consists of a load-carrying primary structure, and of 4 propellant and 2 pressure-gas tanks, supported by a secondary structure. A 3 kN pressure-gas-fed engine is assumed as the main transfer engine. Coni-spherical propellant tanks, polar mounted, were compared with spherical tanks, equatorial mounted. Both tank types are equipped with surface tension zero-g propellant management devices. The applicability of the super plastic forming (SPF) process compared to a forging process for this propellant tank size (1100 mm dia) was studied. Concerning the primary structure, a truss-framework structure was analyzed versus a sandwich-shell structure. The favorable OPM-candidate for the medium/longer term future comprises coni-spherical propellant tanks, SPF-processed and polar mounted, and a truss framework structure connecting the heavy spacecraft to the launcher.