A historic chapter in planetary exploration draws to a close on Sunday when the space probe Galileo plunges into the atmosphere of Jupiter.
By Helen Briggs
BBC News Online science reporter
The giant volcanoes of Io and the hidden oceans of Europa were complete mysteries until the Galileo space craft arrived at Jupiter.
It has returned a wealth of data
It flew close to the icy moons of the planet, discovered by the astronomer Galileo Galilei in 1610.
The probe has travelled almost three billion miles since its launch but now, after 14 years of exploration, it is about to make its final encounter with the largest planet in the Solar System.
It will burn up in a trail of fire as it enters the dense atmosphere around the planet.
The mission is regarded as a landmark in space history and scientists are sorry to see it go.
"It's sad to see it end but if it didn't die with a bang, it would have died with a whimper," says Fred Taylor, professor of physics at Oxford University, who has worked on the project for 30 years.
The fifth planet from the Sun
Largest Solar System world
Would contain 1,300 Earths
Gas giant with small rock core
Galileo has given the first real insight into Jupiter as a planet, he says, with its omnipresent storms and a complex cloud system.
The data has also shed light on the composition of the gas giant and how the early Solar System was formed.
Scientists are still sifting through the treasure trove of new information about the fifth planet from the Sun and will do for years to come.
"It's had a good run - it's left us with an atlas of all the minor satellites of Jupiter," says Tony McDonnell, professor of planetary sciences at the UK's Open University, Milton Keynes.
Galileo was one of Nasa's Rolls Royces", he says, a fleet of big, expensive space craft developed at the Jet Propulsion Laboratory in Pasadena, California.
The last of this generation is the Cassini space craft, a "sister" to Galileo.
Cassini, which carries the European Space Agency's Huygens probe, is visiting Jupiter's neighbour, the ringed giant Saturn and its moon Titan.
In July next year Cassini will begin a four-year tour of Saturn and its moons, opening a new chapter in the study of the outer planets.