Tomorrow, the Cassini-Huygens spacecraft will fly past Phoebe, one of Saturn's many moons and one of the most mysterious bodies in the solar system.

The craft will send back pictures 1000 times more detailed than those produced last time Phoebe was photographed, when Voyager 2 swung past in 1981. The pictures below, sent back earlier this month, are already twice as good as any that have been seen before and reveal a substantial amount of detail. For example, the shadows suggest a surface covered in deep craters and tall mountainous peaks.

Scientists hope the data Cassini-Huyges sends back, which will include spectroscopic and radar data, will help them learn more about the composition of the moon. The ESA says the mission will help with unanswered questions such as did Phoebe ever melt? Does it have evidence of past interior melting? Was it ever an icy body?

Just 220km in diameter, Phoebe is in a very peculiar, retrograde orbit, and is very dark. Scientists speculate that it could be a body from the distant Kuiper belt, way out in the outer solar system. ®

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