Destination Titan: Ralph Lorenz recalls launch day
8 April 2011 Last updated at 11:30 BST
The scientists behind a joint Nasa-Esa mission to Saturn and its moons have spoken about their roles in, and recollections of, the project.
Cassini-Huygens was launched in October 1997 and took seven years to reach the ringed planet.
The Huygens probe was released from the Cassini orbiter on Christmas Day 2004 to begin its journey to the surface of the moon Titan.
One of the men who worked on the probe, Ralph Lorenz, recalls watching the launch and thinking for a moment that it would not succeed.
Destination Titan is broadcast on BBC Four on Sunday 10 April at 2200 BST