In the vacuum of space, where temperatures can plunge to -455°F, it might seem like keeping things cold would be easy. But the reality is more complex for preserving ultra-cold fluid propellants—or fuel—that can easily overheat from onboard systems, solar radiation, and spacecraft exhaust. The solution is a method called cryogenic fluid management, a suite of technologies that stores, transfers, and measures super-cold fluids for the surface of the moon, Mars, and future long-duration spaceflight missions.