All that ice and water is what would protect life, not an atmosphere. Europe has huge warm water oceans, in some estimates more water than Earth. It may have hy

All that ice and water is what would protect life, not an atmosphere. Europe has huge warm water oceans, in some estimates more water than Earth. It may have hydrothermal vents from tidal heating, providing everything required for life. Or so the story goes. Both Europa and Titan are technically ocean worlds, but the likelihood of Titan containing life is much lower I think, given it is so cold that methane is the main surface liquid.