A University of Alabama engineering professor is working with NASA investigators on the development of the nation's first new rocket ship in 25 years. Thus better estimates of both internal structural stresses and the effectiveness of aerodynamic controls can be made. These are influenced by the flexibility of the vehicle's structure. The forces acting on an object are dependent on the shape of the object.
All objects are flexible to some extent.
These forces cause the vehicle to flex, or deform, and that changes the forces. Aeroelasticity accounts for how that changes those forces. The experimental x-33 is expected to fly 15 unmanned, suborbital test flights in 1999. It will be capable of altitudes up to 50 miles and speeds of Mach 15. Unlike the shuttle, the RLV would be completely reusable and would become the world's first single-stage launch vehicle.