Could ice make a good habitat like an igloo for colonists or as cold storage for fuel? Could the cavern be sealed and then carbon dioxide melted to create pressure inside the cavern to grow plants or to work without a pressurized suit? How thick does the ice have to have a pressure of 14 psi?
What is the mixture of carbon dioxide and water in the Ice? I would also guess there would be pockets of carbon dioxide and/or layers of each depending on the weather and other factors for that year.
Using a multi-mission radioisotope thermoelectric generator, heater.
Remember when I told you to stop mixing irrelevant tech to your questions ? This is a textbook exemple. The underlying technology used to generate heat is irrelevant to your question, is poorly phrased, and just makes it harder to read/understand. $\endgroup$