NASA’s Cassini samples watery plumes of Saturn’s moon

By Barry Eitel

SAN FRANCISCO

NASA’s Cassini probe on Wednesday visited an icy moon of Saturn that contains a vast ocean of liquid water beneath its frozen surface and has the potential to support life.

Cassini hovered just 49 kilometers (30 miles) above Enceladus, far closer than any previous mission. It dove through icy plumes shooting from the moon’s south pole. Scientists hope water samples from these plumes will provide clues to the molecular makeup of Enceladus’ inner ocean and of the satellite 1.3 billion km (790 million miles) from Earth.

In September, NASA announced that data from Cassini leads researchers to believe the huge amounts of water on Enceladus is not frozen all the way through. Astronomers have long posited that finding liquid water outside Earth is likely humanity’s best bet to find alien life.

“Enceladus is not just an ocean world - it's a world that might provide a habitable environment for life as we know it," Cassini program scientist Curt Niebur told reporters in a briefing Monday. “On Wednesday we'll plunge deeper into that magnificent plume coming from the South Pole than ever before. And we will collect the best sample ever from an ocean beyond earth.”

When Cassini recorded jets of water spouting from Enceladus in 2005, astronomers listed it as one of the top candidates for finding alien life. The liquid jets also meant the probe did not have to conduct any drilling or digging, and they could even contain microbes.

Even though Cassini does not have instruments that can detect life, it can provide scientists with a better idea about whether Enceladus’ ocean can support it.

“Cassini was not specifically designed for this kind of maneuver – sampling active cryovolcanic plumes – but it has a powerful suite of science instruments that made this sort of science possible,” NASA said in a statement Wednesday.

NASA launched Cassini in 1997 and it entered Saturn’s orbit in 2004, where it has encountered the planet’s moons and frozen rings. The probe is scheduled to pass through the rings of Saturn next year. When it runs out of fuel in 2017, NASA will destroy it by sending it through the planet’s atmosphere.