Future visitors to Europa, one of Jupiter's moons, may find that the vast quantities of water there are unfit to drink. According to instruments on the Galileo spacecraft, the water on Europa is salty. Europa is considered a prime candidate for life outside the Earth, and is one of the few places in the solar system where liquid water can be found. Scientists matched results from the Near Infrared Mapping Spectrometer (NIMS) on Galileo with spectral lines from magnesium sulphates and sodium carbonates measured in the laboratory (Science 280 1242).