Nasa scientists are preparing to say farewell to the Cassini space probe tomorrow as it begins its spectacular suicidal dive into Saturn's atmosphere.

The 22ft robot craft will break into fragments and burn up as it ploughs into the ringed planet's cloud tops at about lunchtime on Friday, ending a 20-year mission that cost £2.9 billion.

Cassini was launched in 1997 and took seven years to travel two billion miles to Saturn, before embarking on a 13 year journey of discovery that delivered a wealth of scientific data on the planet and its moons.

Here's everything you need to know about Cassini and how it will meet its ultimate fate.