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 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 ) during the orbital phase of the mission.