Ice on Mercury!

[Dr Mordrid]

Messenger's making some interesting findings including ice at the poles, perhaps more that on the Moon. Perhaps a rover or human landing could be made in those areas that are in permanent shadow.

LA Times....

[Brian Ellis]

At ~-40°C or F, even mercury will be frozen solid!

[Dr Mordrid]

Thankfully spacesuits & habs can take -200 °F to +250 °F and keep the inhabitants safe.

[degrub]

and the shielding for the radiation flux ?

[Dr Mordrid]

If the mission flies during a solar minimum then x-rays from flares and particles would be minimzed. That and land on the night side & don't stay long.

The best shielding for particles is a hydrogenated polymer, paraffin or water. Bigelow's modules provide 16" of polymers and 2.5" of water, so that's covered.

For X-rays there is a problem: the mass of a lead or tungsten shield. This can be minimized by using a shadow shield - a smaller shield that always faces the sun during transit. There is also the problem with a metal gamma shield as it can be a double edged sword; reducing direct gamma while actually producing more lower energy gammas due to particle impacts. This secondary radiation is usually more easily absorbed, so a lot of the time you're better off with the higher energy stuff and keeping the transit as short as possible.

These traditional shields may be surpassed by recent developments; one being work on artificial magnetospheres for charged particles and metamaterials that may be able to re-direct gamma radiation around a spacecraft - not unlike the invisibilty cloaks in the labs can redirect light and radar around an object. Another that wss recently patented uses Widom-Larsen theory effects (link is to pdf).