The terminal and smells of hydraulics and motors are now well behind us and the status console indicates NORMAL operating conditions. It is no longer possible to look at the tube structural support rings as they pass at a rate faster than the flapping of hummingbird wings.

As the tube slowly turns to go around and through mountains, the pod rotates like a banking roller coaster keeping our sense of gravity directed down through our seats.

The on-board stereo is softly playing the soundtrack from a popular science fiction space trek show and my mind links up with a scene from an episode where the space ship is propelled to a distant part of the galaxy by mental control of thought, time, and energy. I am awakened from this brief daydream by a yellow WARNING sign above each seat and a soft professional automated voice instructing passengers to place their heads against the head rest for the upcoming increase in acceleration.

Just moments ahead is the greatest design challenge of the whole system: analysis of the geometric, thermal, and dynamic parameters of the wind tunnel throat such that this high volume of air will indeed transition from subsonic to supersonic speeds as the tunnel re-expands. While reflecting on the many details studied during the design phase, my mind wanders for an instant to the many potential applications to use this mode of high speed transportation. A ski lift in the Wasatch mountains, underwater transoceanic links from San Francisco to China, satellite launchers, postal payload and letter delivery networks, and large scale, 100 plus passenger models, like a commercial aircraft or train fuselage with no wings, tail, or landing gear. My reflection is interrupted by a subtle vibration caused by a shock wave forming on the leading edges of the pod…