Cassini at Enceladus

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For the second time this year, the Cassini spacecraft is about to get a shower. It'll fly through plumes of water that jet into space from the south pole of Enceladus, one of the moons of Saturn.

Enceladus is a big ball of ice. Its average surface temperature is around 330 degrees below zero Fahrenheit.

But early in its mission, Cassini discovered "hot spots" near the south pole. They're along four large cracks known as "tiger stripes." Temperatures are a couple of hundred degrees warmer than anywhere else on Enceladus. And that's where the plumes of water are coming from.

The gravity of Saturn may be responsible for both the cracks and the plumes. In this scenario the planet's gravitational pull has caused the surface to crack. The sides of the cracks rub together, melting some of the ice just below the surface. When Enceladus is closest to Saturn, the cracks open up and some of the liquid water jets into space.

Cassini flew through these watery plumes back in March. It wasn't hurt, but the plumes were strong enough to push the craft a little bit. It'll fly through the plumes again tomorrow, snapping the best pictures of the south pole region to date.

This won't be the last encounter with Enceladus, though. A couple of months ago, Cassini began a two-year extended mission. The new mission will include six more passes by Enceladus. At least a couple of passes will include a cold shower for the hard-working spacecraft.

Script by Damond Benningfield, Copyright 2008

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