Re: manned Mission to Mars discussion
Those "atmosphere ponds" are still very good vacuums by earth standards and would not provide any more appreciable radiation shielding.
The argument for missions to Phobos are from a logistics standpoint. It has no gravity to speak of so can be easily "landed" on or docked with. It is thought to have a large amount of water ice for a core making it a natural fuel depo. Being virtually weightless would make it easy to create a radiation shielded structure. Once you have a decent base worked up, you can then explore mars at your leisure with a safe haven in orbit.
Baby, you and me were never meant to be, just maybe think of me once in a while...