Thermal radiation is an order of magnitude less efficient than other forms of heat transfer, but it gets the job done. It helps that you're radiating to the dea

Thermal radiation is an order of magnitude less efficient than other forms of heat transfer, but it gets the job done. It helps that you're radiating to the dead of space, which is near absolute zero (efficiency is dependent on the black-body temperature of what you're radiating "to"). That's the why the radiators have to be so huge, and are kept out of direct sunlight.