Electromagnetic Augmentation Can Reduce Space Launch Costs

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 EM augmentation of the chemical boost capability for a two-stage-to-low-Earth-orbit system, with the extreme case being a complete EM launch. Several EM acceleration options are available, but railguns were chosen for this study. The second stage of the system was assumed to be a chemical rocket or a reusable scramjet to carry a reusable orbiter vehicle into low-Earth orbit. EM launch systems of this type will be governed by the same fundamental principles as tactical guns, but one major difference will be that the EM accelerator track, which may be several kilometers in length, will not be powered only from the “breech” as in a tactical gun, since electrical resistive losses will be 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. Present pulsed-power approaches will require many launches to offset the capital cost. Novel pulsed-power concepts or low-cost manufacturing approaches will need to be developed for such a concept to be economically attractive.