As a result, the engines occupy a large area beneath vehicle and the need to accomodate a large quantity of fuel means that an all-body shape is most feasible. Structurally, the all-body shape is highly efficient. As well as being extremely aerodynamic, the average cross-sectional area being very large provides a great deal of space for load, equipment and fuel. This being inside a structure that is light and compact having a relatively small surface area to generate frictional drag. The spyplane's airframe may incorporate stealth technology, but it doesn't really require it should its mission simply involve high altitude reconnaissance.
Hypersonic aircraft are much harder to shoot down than a ballistic missile.
Although a hypersonic plane isn't very maneuverable, its velocity is such that even a small turn puts it miles away from a SAM's projected interception point. Choosing the right type of fuel is crucial to the success of Aurora. Because various sections of the craft will reach cruising-speed temperatures ranging from 1,000 degrees fahrenheit to more than 1,400 degrees fahrenheit, its fuel must both provide energy for the engines and act as a structural coolant extracting destructive heat from the plane's surface. The plausible solution is cryogenic fuel. The best possibilities are methane and hydrogen.