Projectile Nosetip Thermal Management for Railgun Launch to Space

A major issue in achieving direct launch to space using electromagnetic railguns from the surface of the earth is that we are at the bottom of a gravity well, requiring very high launch velocities to achieve orbit insertion. The atmosphere is most dense at the earth's surface-this, combined with high velocity, leads to very stressing thermal conditions for the launch aerobody. To minimize aerodynamic losses, a typical hypersonic flight body is a blunt slender cone. The thermal loads are greatest on the nosetip of this cone, and for small bodies (<10 kg) the thermal loads may exceed the capabilities of present passive thermal protection systems, such as dense, ablative carbon phenolics. Even for launch from a high-altitude airborne platform, aerothermal loads can be considerable unless rocket assist is provided. This paper discusses aspects of the launch package and characteristics of the railgun needed to achieve orbit insertion velocities