What happens to surface water on Callisto under its current atmospheric conditions?

Answer

Water would sublimate (go directly from ice to gas).

Because the existing atmosphere is too thin to support surface liquid water, water ice exposed to the environment would transition directly into a gaseous state.

What happens to surface water on Callisto under its current atmospheric conditions?

#Videos

Colonizing Callisto - Third Largest Moon In The Solar System

Universe Sandbox 2 - Terraforming the Moons of Jupiter (Io, Callisto ...

SpaceJupiterMoonterraformingCallistoterraform