
Ithnaar |

The (almost) vacuum of space is a near perfect insulator. You need heat sinks to bleed off the heat your body generates.
Armor does protect from vacuum in starfinder.
While it is true that objects in a vacuum cannot dissipate heat energy via convection or conduction (like we do in an atmosphere), they *do* dissipate heat by radiating infrared radiation, which they do constantly.
Famously (and correctly) depicted in the movie Apollo 13, when they didn't have enough electrical power to run the heaters, the cabin temperature dropped to 38 degrees Fahrenheit (3 Celsius), despite having three sweaty astronauts inside.
It depends on how close you are to the sun and how exposed you are to it. If you stand in the dark in a place with no atmosphere, you get chilly rather quickly.