What causes the superheated plasma sheath surrounding a spacecraft during high-speed reentry?

Answer

Aerodynamic heating from rapidly compressing air in front of it

The immense thermal energy is generated primarily through aerodynamic heating, where air molecules ahead of the vehicle are compressed so quickly at speeds over Mach 25 that they turn into a superheated plasma.

What causes the superheated plasma sheath surrounding a spacecraft during high-speed reentry?

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