Space is not absolute zero, absolute zero is the temperature that all atomic movement stops (Third law of thermodynamics since you seem to like them so much) and is impossible due to quantum mechanics (Heisenberg uncertainty principle).
Also, since space is the closest natural approximation of a vacuum (due to no vacuum being perfect) heat would have an incredibly difficult time travelling through convection, conduction, or advection, and would travel mostly through radiation which would make it incredibly difficult to travel entirely through a moon and get to wherever the ship searching for the ship hiding is and then have them figure out it is a ship and not radiation from the moon itself. Also, if the ship hiding turned off unimportant heat generating machines, he would be even more concealed! All he would have to do after that is turn off active sensors and communication! In conclusion, Heat stealth is completely possible.
(Also on the whole super-glass thing you could probably use some form of light sensor considering it would be quite useful)