Thermal Protection-, Aerodynamics- and Control Simulation of an Electromagnetically Launched Projectile

Abstract

In recent years several ideas came up to apply electromagnetic launch technology for spaceflight applications. Using electric energy to propel a payload carrier promises the saving of propellant and therefore cost reduction for the transfer to orbit. The conducted studies mostly comprise of a rough estimation of the launcher and the vehicle size. Sometimes a Δv-budget is given to illustrate the energy expenditure. Some of the studies neglect the necessity of a rocket engine. Only by means of an electromagnetic launch without the capability to maneuver, an orbit is not achievable. The high acceleration and the high velocities at low altitude evoke high demands on the payload carrying vehicle. Its structure has to withstand the high acceleration forces during launch and the tremendous aerodynamic heat fluxes during the ascent flight in the dense atmosphere. Moreover a propulsion system, an attitude control system, and a flight controller are needed to bring the vehicle into a circular orbit. This paper presents a vehicle concept that addresses all these demands. The vehicle comprises of a two stage hybrid rocket engine system, a thermal protection system, high test peroxide monopropellant thrusters for attitude control, and a guidance, navigation and control system. A simulation model is created, that consists of a 6-DOF flight mechanics module, aerodynamics model, propulsion module, thermal protection system simulation, as well as of guidance and flight control simulation. Therefore, the complete ascent with all its aspects can be simulated. The simulation results show that a 710 kg vehicle launched with 2586 g and an initial velocity of 3642 m/s can carry 31.5 kg of payload into a 300 km circular orbit. The configuration of the vehicle can be defined by a set of input parameters. This allows using the model within an optimization tool.