The Chemistry of the Air

As a hypersonic aerodynamicist, you actually become an aerothermal chemist. You have to take into account all those species of gas when you're solving your fluid flow equations. As you get to about 12 to Mach 15, the ions begin to form and you start stripping off electrons from these molecules. And that's because of this plasma that's forming around the outside of the vehicle. Everybody's familiar with these radio blackouts, Apollo and the space shuttle and all these re-entry vehicles went through.