In the first of a long, sinuous string of things that have to go right for this to work, the Huygens part of the Cassini-Huygens Saturn probe detached successfully tonight.

20 days from now, on January 14th, the flying saucer-shaped intruder will parachute onto the surface of Titan, the orange, methane-shrouded Saturnian moon.

What happens after that is anyone's guess. Titan is thought by some scientists to be covered in oceans of liquid methane, so the brave little probe may just sink beneath the waves.

In point of fact, Huygens really has no landing gear to speak of, so getting any data from the surface at all is dicey. It's more suited to sample the air up there. The dauntless machine comes equipped with plenty of sensors and cameras though, so assuming its frozen parachutes open, we should learn quite alot about one of our solar system's most interesting destinations.