Launch to space with an electromagnetic railgun

Many advances in electromagnetic (EM) railgun and power supply technology have been made in recent years. Laboratory experiments with railguns have demonstrated muzzle velocities of 2-3 km/s and muzzle energies >8 MJ. The extension of this technology to the muzzle velocities (/spl ges/7500 m/s) and energies (/spl ges/10 GJ) needed for the direct launch of payloads into orbit is very challenging, but may not be impossible. For launch to orbit, even long launchers (>1000 m) would need to operate at accelerations >1000 gees to reach the required velocities, so that it would only be possible to launch rugged payloads, such as fuel, water, and material. A railgun system concept is described here and technology development issues are identified. Estimated launch costs could be attractively low (<$600/kg) compared with the Space Shuttle (>$20 000/kg), provided that acceptable launch rates can be achieved. Further evaluations are needed to establish the technical and economic feasibility with confidence.