I read in July's Popular Science that Bart Rutan's SpaceShipOne is designed to essentially fall back to earth rather than follow a glide path. The idea was to avoid having to install expensive and heavy avionics and controls to stabilize the craft and to reduce heating.
I always thought the Space Shuttle followed a glide path to reduce heating, yet it reaches 3000 degrees F. Rutan's ship is only supposed to reach 1000 degrees, and he uses a slathered on heat shield over a carbon fiber body.
Would it heat less because it comes down quicker and so has less time to build up heat? I thought the straight fall would increase the heat, not decrease it.
Also, X15 pilots have said the 3.5 g's was hard on their hearts. SpaceShip one is supposed to produce 5.5 g's on re-entry. Does anyone know what's acceptable in g forces?