15 October 1997: Cassini blasts off from Cape Canaveral, Florida, carried by a powerful Air Force Titan IV/B Centaur rocket. It is the heaviest satellite ever sent into space, weighing in at a massive 5.5 tonnes: more than half of that weight is fuel for the 3.4 billion kilometre journey ahead of it, which will send it looping past Venus and Jupiter on its way to Saturn. It will take about seven years for the craft to arrive at its destination, where it will spend four more years investigating the ringed planet and its moons. In January 2005 the Huygens probe, which is hitching a ride on Cassini, will drop through the atmosphere of Saturn's largest moon, Titan, to investigate what lies beneath its smoggy clouds.