Nowhere are speed, cost and safety more critical to economic success than on the space frontier, where only the most lucrative of returns have been able to justify the expense and risk. The first such gold from the space frontier has been information transmitted via communication satellites, which has enabled an explosive growth of telecommunications and consequent globalization of business opportunity. The high cost and risk is due largely to the physical difficulty involved in overcoming the fact that we live at the bottom of both a gravity well and an ocean of air. Speed is needed, both to reach orbit, and to reach distant destinations across the hostile environment of space. Speed requires concentrated energy sources and storage, the more so the greater the distance.
Speed requires conversion of energy into thrust with utmost efficiency, and utmost effect.
Speed requires vehicle structures that are heat resistant and strong, yet as simple and light as possible.