Frictions exerted during atmospheric reentry are sufficient to turn spaceships into comets of flaming slag if not adequately mitigated – a nice outcome when deliberate, but virtually always extremely disastrous otherwise. When it was still in operation, the Space Shuttle was meant to strike the outermost margins of the Earth’s atmosphere at roughly Mach 25 (17,000 MPH), then ride a wave of superheated plasma down into the atmosphere until aerodynamic surfaces regained their efficacy.
NASA says that “using air drag is the most mass-efficient means of slowing down a spacecraft.” The Shuttle depended on layers of ablative heat shielding tiles that would melt and peel off, transporting more heat away with them, to withstand those severe 3000-degree F temperatures, but NASA has something better in mind for tomorrow’s reusable spaceship, something inflatable.
