Combined Propulsion System Analysis ans Stage Impact Evaluation for a green Propellant Kick Stage with the focus on modular kit approach

Kurzfassung

Currently, ArianeGroup is developing a Kick Stage for the new Ariane 6 heavy-lift launcher. The baseline Kick Stage design foresees the utilization of conventional storable propellants, which shall be replaced by less toxic and green propellant alternatives in the future. This thesis continues with first, preliminary assessments of a green Kick Stage Propulsion Subsystem evolution on the example of the Ariane 6 Kick Stage, which identified hydrogen peroxide and propane as a potentially suitable propellant combination. First, a broad system description of the Ariane 6 launcher and the baseline Kick Stage Propulsion Subsystem are summarized. Then, customers and their expectations on a green Kick Stage are identified. Based on this, system boundaries are derived by utilizing selected System Engineering engine processes for early system studies. Subsequently, selected key constituents of a Propulsion Subsystem are theoretically examined and preliminarily designed. Different potential tank geometries are sized and compared. Also, a pressure-fed and two turbopump fed system configurations are estimated in size, mass, and required pressurant gas for this purpose. Furthermore, monopropellant and bipropellant thrusters are compared. In the scope of this thesis, cylindrical propellant tanks were identified as recommended design option. The preliminary sizing of the turbopump configurations indicates potential system mass savings for the cost of an increased complexity. The discussion of the turbopump mass estimates identified recommendations for further assessments. Furthermore, suitable off-the-shelf high-pressure tanks were found for the calculated pressurant gas volumes. Bipropellant thrusters, utilizing the main engine’s propellant combination with a common laser ignition system, are considered a viable option for the Reaction Control System. An established system mass summary revealed an increased Kick Stage inert mass compared to the baseline. Paired with the disadvantageous specific impulse of the considered propellant combination, a worsening of system performance is to be expected. Options to use cryogenic propellants instead were discussed. Last, recommendations for subsequent analyses were given.