Mission analysis of a low-cost re-entry test vehicle

Abstract

Part of nowadays hypersonic design methodology for reentry vehicles and future launch systems is the combination of numerical simulation, ground-based experiments such as wind-tunnel tests, and the application of flight-test vehicles. Small and low-cost reusable re-entry vehicles can be a good means for doing hypersonic research, testing new heat-resistant materials, and qualifying newly developed sub-systems in a realistic environment, because of its frequent and repetitive use. In this paper, such a vehicle will be analysed. The focus of the analysis is directed on critical mission and design issues. The re-entry vehicle will be launched with the Brazilian VS40 rocket, that has a maximum burn-out velocity of about 3300 m/s at an altitude of 120 km, for a payload mass of around 250 kg. This results in a maximum Mach number at lower altitudes between 10 and Il. The vehicle geometry is based on a trapezoidal cross section and a sharp, watercooled nose that allows for a high lift-to-drag ratio, a reaction-control system and four flaps mounted at its base for aerodynamic control. The guidance system is a simple feedback system that enables entry with a constant angle of attack, then a pull-up manoeuvre and subsequent flight at a constant altitude. The attitude control system is a so-called Linear Quadratic Regulator, designed from optimal-control principles.. Critical mission issues that are discussed, are the launch including the separation of the re-entry vehicle, the subsequent exoatmospheric flight, the nominal re-entry and the aerodynamic control during the horizontal flight while executing a bank manoeuvre. Furthermore, the preliminary thermal structural design of the vehicle is addressed.