Space is 2.7K, in other words, it is extremely cold.
The pressure in space is almost zero PSI so the boiling point of water is far below body temperature. If they don’t have vacuum seal to maintain pressure, their bodies would explode from the violent boiling of their water content. Another risk most people are not aware of.
Right, and it's a vacuum. So where did the astronaut's body heat go with such an extreme difference in temperatures, when radiation is the only method that would work?
I believe that’s the interstellar temperature of big bang cosmic radiation.