Farewell to Cassini

As I'm writing this, Cassini's last data-stream has just crossed the orbit of Jupiter en route to mission control back on Earth.

It's hard to explain what a monumental achievement the mission has been, so I'm going to start with a page from my 1999 edition of D.K.'s 'SPACE Encyclopedia' (my enthusiam for all things astrophysical took hold... early).

At the age of nine, five years seemed like an obscene amount of time to have to wait for anything. But it was well worth the wait. For the last 13 years Cassini has been doing science, sending back fantastic images and producing new results. We've had a view beneath the impenetrable clouds of the mega-moon, Titan, courtesy of the Huygens lander - complete with liquid methane lakes and seas. We've discovered a sub-surface ocean on the frozen moon Enceladus. Innumerable close-ups of Saturn's defining feature, its extensive ring-system.

But all good things come to an end. The mission ends now with the probe skidding across the upper atmosphere of Saturn, a procedure that will burn it up and absorb its momentum, so that the embers will then fall below the cloud tops down to the depths of Saturn. It's a dramatic end for the mission and ought to provide a hell of a close-up! Time to say goodbye...