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

Kurzfassung

In recent years, several ideas to apply electromagnetic launch technology to spaceflight applications have come up. The use of electric energy to propel a payload carrier promises savings of propellant and, therefore, cost reduction for the transfer to orbit. Previous studies mostly comprised a rough estimation of the launcher and the vehicle size. Sometimes, a Dv-budget is given to illustrate the energy expenditure. Some studies neglect the necessity of a rocket engine. Only by means of an electromagnetic launch, without the capability to maneuver reaching an orbit is not achievable. In addition to a propulsion system, an attitude control system and a flight controller are needed to bring the vehicle into a circular orbit. The high acceleration and high velocities at low altitudes have set 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 ascent through the dense atmosphere. This paper presents a vehicle concept that addresses all these demands. The vehicle consists of a two-stage hybrid rocket engine system, a thermal protection system (TPS), and high-test peroxide monopropellant thrusters for an attitude control system and a guidance, navigation, and control system. A simulation model is created, which consists of a 6-DOF flight mechanics module, an aerodynamic module, propulsion module, TPS simulation, as well as a 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 the use of the model within an optimization tool.