Cassini Enceladus flyby: Saturn's moon to be examined for the 'ingredients of life' as spacecraft flys through huge spray of ice

Experts say the mission is an attempt to find out whether the moon could have 'the ingredients for life'

(Nasa)

A spacecraft is to be sent through a fountain of icy spray that is coming out of an alien ocean that could have life within it.

The Cassini craft is to fly past Saturn’s moon Enceladus. And scientists hope that it can come to understand the makeup of the mysterious watery world, which some scientists think could have life beneath its surface.

Scientists have already confirmed that there is an ocean covering its entire globe, underneath its icy shell.

And this week the probe will fly through a geyser that is shooting out of the moon’s south polar region, about 30 miles above the surface.

During the approach, instruments on board the craft will sample the spray and analyse the cocktail of chemicals within it.

Higher plume encounters have been made before, but the low sweep will allow Cassini to access heavier molecules including organics.

Dr Curt Niebur, Cassini programme scientist at the American space agency Nasa's headquarters in Washington DC, said: "This incredible plunge through the Enceladus plume is an amazing opportunity for NASA and its international partners on the Cassini mission to ask, 'can an icy ocean world host the ingredients for life?"'

The plume is fed by icy geysers which blast 250 kilograms (551 pounds) of water vapour, ice grains and volatile chemicals into space at 1,360 mph and are thought to have a fiery origin deep beneath the moon's surface.

They have been compared with hydrothermal vents on Earth - volcanic fissures on the ocean floor where sea water percolating through fractures in the bedrock is heated to high temperatures.

The complex chemistry around hydrothermal vents gives rise to oases of teeming life in some of the deepest, coldest and darkest corners of the world's oceans.

One of Cassini's chief missions is to find evidence of hydrothermal activity on Enceladus.

Dr Hunter Waite, from Southwest Research Institute in San Antonio, Texas - who is team leader for the craft's neutral mass spectrometer instrument (INMS), said: "Confirmation of molecular hydrogen in the plume would be an independent line of evidence that hydrothermal activity is taking place in the Enceladus ocean, on the seafloor.

"The amount of hydrogen would reveal how much hydrothermal activity is going on."

The plume was first spotted by Cassini in 2005, a year after it arrived in the Saturnian system.

Around 100 geysers erupting from surface features known as "tiger stripes" were identified as its source.

The four 1.2-mile wide aligned cracks are believed to be sites of heightened volcanic activity on Enceladus.

Additional reporting by Press Association