Publisher Summary The development of ballistic missiles has made rapid progress. One of the consequences of this development is that classical aerodynamics is found insufficient for the description of flows with high velocities. Today, almost all branches of physics need to be studied to treat certain problems connected with those high velocities. While the results obtained in completely different fields of inquiry can be partly taken over, the technical development has been so rapid that physical situations, which are yet to be correctly understood, occur. It has become a matter of course that missiles fly at high altitudes, but little is known about the flow pattern at these altitudes, where the mean free path of the air molecules is comparable with some characteristic dimension of the projectile.