The Cassini probe, the unmanned spacecraft sent to the planet Saturn, is all set to make a daring close flyby of Enceladus, the brilliant white moon of Saturn, BBC News reports.

The NASA craft will sweep just 50km above the moon's surface in a final attempt to "taste" the chemistry of water jets spewing from its south pole.

Enceladus has produced a series of major discoveries that mean it is now considered one of the most promising places to find life beyond Earth.

Scientists say it has an ocean beneath its icy crust.

What is more, the conditions in this global body of liquid water could be benign enough to support microbial organisms. "Enceladus is not just an ocean world - it's a world that might provide a habitable environment for life as we know it," said Cassini program scientist Curt Niebur, in a media briefing on Monday.

Cassini will attempt to detect molecular hydrogen during Wednesday's encounter.

This would be a strong signal that hot vents exist on the rocky ocean floor.

If that is the case, it would be another plus-point in the moon's habitability potential.

Such vent systems are known on Earth to provide the fundamental energy and nutrient requirements for some deep-sea ecosystems.

At these locations, water is drawn into the rock bed, heated and saturated with minerals, before then being ejected back upwards.

Whether any of this is going on inside Enceladus is just speculation for now.