Electromagnetic Launch to Space

A study was undertaken to determine if a ground-based electromagnetic (EM) acceleration system could provide a useful reduction in launch-to-orbit costs compared with current large chemical boosters, while increasing launch safety and reliability. The study evaluated the launch of a two-stage-to-low- Earth-orbit projectile, with the initial velocity being provided electromagnetically and the orbit insertion via a rocket motor. Several electromagnetic accelerator options are available but railguns were chosen for this study based on their demonstrated performance capabilities. The second stage of the system was assumed to be a chemical rocket that would carry a payload into low-Earth orbit.Electromagnetic launch systems of this type will be governed by the same fundamental principles as tactical railguns with a major difference being that the EM accelerator track–which may be tens or hundreds of meters in length–cannot be powered only from the “breech” as in a tactical railgun, since electrical resistive losses will become unacceptably large. To overcome this, a distributed feed system will be required.This study shows that the capital cost of the pulsed power system for the EM accelerator will dominate the system economics. With present pulsed power approaches, multiple launches will be required to offset the capital cost and provide low costs. The development of novel pulsed power concepts and/or low-cost manufacturing approaches will ensure that the EM system will be economically attractive and options for such approaches are discussed.