Jiminies!!! This is the best hope yet! Our own atmosphere gets to about -173*F at about this range. And not only finding water vapor but to find organic chemicals too! This is so exciting.
"The spacecraft found a high density of water vapor and both simple and complex organic chemicals as it passed within 50 kilometers (30 miles) of Enceladus on March 12 to assess the geyser-like plumes shooting out from surface fractures, the space agency said.
Cassini's instruments detected temperatures on Enceladus's south pole hot-spot as high as minus 135 degrees F (minus 93 C), which suggested that sub-surface temperatures might be high enough for the existence of liquid water, one of the keys to possible life, John Spencer, one of the scientists on the Cassini team, told a news conference."
Of course it doesn't mean there are little green men or anything, but it means that they have the beginnings of primodial stew.
As a former pre-aerospace geek I am doing a happy dance like you wouldn't believe!!!!