Why is there a glowing, white contrail that stretches from horizon to horizon as the orbiter crosses overhead before landing?
The orbiter’s speed heats the surrounding atmosphere to several thousands of degrees Fahrenheit. This temperature is great enough to strip some electrons from atoms in the air, creating an ionized plasma. The free electrons generate visible light as they escape from and recombine with atoms. This luminous “ion sheet” or “plasma trail” is fundamentally different from a conventional jet airplane contrail, which would be invisible on a moonless night.
