Hab Commander
From OCE Space Simulation
The habbitat, or "hab commander" is the head astronaut in the habitat. He has total control within the habitat and is the highest on the blame list. However, he is still; subject to the rulings of Mission Control.
Usualy, though not always, the Mission Commander who happens to be an astronaut is appointed this task. However, when both mission commanders decide to work in mission control, a seperate habitat commander is chosen.