The newest Andromeda-class battlecruisers come equipped with a startling capability: stealth.
See, there’s a problem in space. Space is big and, well, quite empty. You can’t hide anywhere, except behind something like a planet–which puts a limitation of practicality, since 99% of the time, ships aren’t anywhere near the vicinity of planets.
So you’re tasked with the problem of hiding an enormous hunk of metal in wide-open spaces where anybody with an IR telescope can see you coming probably a billion kilometers away, since your 290-Kelvin hab bubble stands out like a searchlight against cold vacuum.
Well, some engineer took a look at that, and decided to just put a refrigerator on the ship pointed outwards. The trouble with that is that the heat you pull from the hull has to go somewhere, and since it can’t leave from the hull, it needs to go back inside the ship. So you’re invisible, but you’re cooking your crew.
There the matter stood, until somebody realized this is actually fine–if you have the right tactics.
You’re invisible, but you’re cooking your crew.
When the U.F.P. Relentless left her construction site in orbit above Mars on her maiden voyage, the first thing she did was turn the coolers on max. Over the long months of the Hohmann transfer to Earth, they dumped her waste heat through radiators into internal compartments of chilled Lithium (chosen for its stability, mass, and specific heat).
The situation could not be maintained indefinitely, of course, but after she had slipped into (retrograde) orbit around Earth, still all but invisible, the external radiators folded out, and the gigajoule or so of waste heat accumulated on the voyage was radiated away against the camouflaging background of an industrialized planet.
For their part, the Jovian Trade Union, comprising the confederacy of city-state greater moons of Jupiter, had dutifully tracked the thermal signature of the decoy ship which remained at Mars, flaming like a candle. And when their troublemaking frigates burned for Earth, they arrived in LEO to a surprise.