Lots of news on Mars these days, including images of snow falling:
Also lots of news coming up on Mercury as the Messenger probe readies itself for a science survey on flyby number two next week.
(T)he Gamma-Ray Spectrometer (GRS) was placed in an “anneal mode” to prepare its detector for optimal performance during the flyby.
“The detector material itself is a high-purity crystal made of the element germanium,” explains GRS Instrument Engineer John O. Goldsten. “In space, the crystal develops defects–atoms knocked out of place–when bombarded by high-energy cosmic radiation, and this degrades the instrument’s performance. Heating the detector to high temperatures promotes realignment in the crystal, a process called annealing.”
This annealing process increases the detector temperature to 84*C for a period of time before lowering it to an operating temperature of -183*C. The annealing will last for two weeks in preparation for Mercury flyby 2 to improve energy resolution and signal-to-background ratio. The GRS detector will be annealed once again prior to the third flyby of Mercury in September 2009, and once every Mercury year (88 Earth days) during the orbital phase of the mission.