Fundamentals of Heat and Mass Transfer had saved them all. Not through brute force or exotic technology, but by reminding him that heat always finds a way—through solids, fluids, or empty space. And sometimes, the emptiest space of all is the one where clever engineers let physics do the heavy lifting.

Kaelen’s first instinct was conduction. “Just sink the heat into the lunar regolith,” he muttered, flipping to Chapter 3. But the numbers were brutal: lunar soil was a poor conductor. The heat would build up faster than it could diffuse. The reactor’s silicon carbide housing would reach critical temperature in under an hour.

Kaelen opened the emergency vent. No coolant, no moving parts—just pure electromagnetic waves carrying energy away. He watched his suit’s thermometer. The reactor’s temperature stopped climbing. Then, slowly, it began to fall.

He worked fast. Outside the airlock, in his bulky EVA suit, he spread the mylar across a twenty-meter metal frame, then coated one side with the black powder. High emissivity on one side, low absorptivity on the other. He angled the black side toward the reactor’s emergency dump port and the shiny side toward deep space. The temperature difference was extreme: the reactor’s outer casing was glowing at 800 K, space was a frigid 3 K.