NASA is considering re-purposing its successful Cassini-Huygens probe to do something that it wasn't designed for, but is nonetheless amazing: searching for signs of life on Saturns frozen moon Enceladus. Back in July 2005 Cassini observed a huge plume of ice particles and water vapour shooting from the tiny moon, suggesting the possibility that there's a liquid ocean hiding beneath its surface.
Now scientists are calling for the probe to be sent sailing through the plume and over the moon in detail to look for complex carbon molecules that may indicate the presence of life in the ocean using its Ion and Neutral Mass Spectrometer. The argument runs that abundant life living in the ocean should produce molecules like methane which could then be detected: scientists have already built a test chamber at NASA's Ames Research Centre to try to simulate the conditions on Enceladus and calculate what kinds of gasses may be expected.
It's a long shot, but it may provide useful data before NASA sends more probes to the gas giants in the next decade. And you never know, we may find out we're not alone. [New Scientist]