Thermal Mechanics and Stealth Post-Combat 2
So! Reviving an old concept that's been posted a few times before, but given the upcoming second combat overhaul, it would be prudent to include the new lock-on mechanics.
Space Engineers already models heat to an extent, with the ambient temperature affecting your suit's battery life - ambient temperature depends on location, time of day if applicable, and pressurisation. Ships, however, remain unaffected by this.
I propose that 'active' blocks - anything that draws more than a few watts of power - should generate heat. Normally, this heat would be manageable, being sunk and radiated by the block as fast as it's generated. However, covering parts of a block should reduce its ability to radiate heat, and reactors, weapons, and thrusters should generate extra heat based on usage.
If the heat of a block passes that block's threshold, it starts dumping that heat into the grid as a whole; the grid has a total threshold of its own that depends on its mass, with larger ships having more mass in which to sink it (and a smaller surface area from which to radiate it). Excessive grid heat will begin to either damage blocks or cause temporary malfunctions and shutdowns.
Heat can also play into the new targeting and lock-on system - particularly hot grids could be picked up and locked onto from further away, and conversely, cold grids should be harder to detect. Also implementing heat vents to allow for extra dissipation capacity, and heatsinks in which to store heat, could introduce emergent mechanics such as silent running; shut off the heat vents and drift by an enemy undetected, at the risk of cooking your ship from the inside.
Heat would also act as a balancing tool for later game blocks, forcing you to either choose between short bursts of effectiveness in compact builds, or adding radiators to give yourself additional time-on-target with the risk of having them shot out.