What is the advantage of being in a colder deep space environment?
Since the Spitzer Space Telescope must operate at the frigid temperature of only 5.5 K, it has to carry its own supply of cryogen (or refrigerant), and a cryostat (“Thermos bottle”) to hold the liquid helium. By immersing Spitzer in a very cold environment to begin with, the Observatory can carry far less liquid helium than if it were orbiting the warm Earth.
