First tier of Mars heat terraforming. Unlike its big brother this thing is inefficient but takes up way less power.
Build the Mars Heat Pump Module in the ShipYard on the Moon and shoot it off from the Gamma 4 Build/Launch Facility
Yields 50 heat a day (24 seconds). Use 4 of these to make the 2x2 Thermal Vent.
Mars terraforming is complete at 1,000M Heat and Gas release. Touch on the "Supplies" box at the top right of the game to see your progress.