This is the Guardian. For years, astronomers believe that our best chance of finding life off Earth was on Mars.

But more recent research has shifted the focus to the deeper darker realms of the solar

system onto the icy moons of the gas giants.

Scientists from the European Space Agency are putting the final touches to a pioneering

mission to Jupiter's icy moons in the hope of finding signs of primitive life. Today a groundbreaking mission

Jupiter icy moons explorer or juice will be blasting off from French

Guyana to visit Europa, Ganymede and Callisto.

So what makes the moons of Jupiter and Saturn such appealing prospects for astrobiologists.

What will the Juice missions be searching for?

And could it be the next chapter in our hunt for extraterrestrial life?

From the Guardian, I'm Madeline Finley,

and this is Science Weekly. Thank you're

Stuart Clark, you're an astronomer, a journalist and author of books including beneath Night Sky, and recently you've written about the so-called

Juice Mission. But first of all, when we talk about the potential for life in our own solar system. What are we actually talking about?

You're not talking about other civilizations or other intelligent beings.

You're talking about microbes.

That may not sound so grand in the sort of science fiction scheme of things.

There's a potential even for a single extraterrestrial microbe to advance

our understanding of what life is, how it may have started.

It's just colossal, for example, does life have to be based on

DNA or can there be another molecule that can carry genetic information and therefore be the basis of a life form.

Questions like that we can't answer just looking at life on Earth so we look for life elsewhere in the solar system in order to perhaps

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