PARIS (AFP) - A US-European exploration of Saturn that has already been lauded as one of the shining achievements in space history is to be extended by two years, the European Space Agency (ESA) said on Tuesday.

Quoting sources at NASA, which is the principal funder of the Cassini spacecraft, ESA said the mission’s scheduled end of July 2008 had been pushed back by two years.

Cassini is one of the most expensive but most successful robot spacecraft ever built.

It went into orbit around Saturn in 2004 after a seven-year journey spanning 3.5 billion kilometres (2.2 billion miles).

The mission comprises a US-Italian orbiter, Cassini, with 12 instruments on board, and an ESA probe, Huygens, laden with six sensors, which was sent down to the moon of Titan on a suicide plunge.

Cassini has sent back 140,000 images in 62 revolutions around Saturn, 43 flybys of Titan — whose strange landscape has given scientists a glimpse of what an infant Earth may have been like — and 12 close flybys of the smaller, icy moons.

One of these moons, Enceladus, is especially beguiling, as it may have liquid water beneath its pristine, frozen shell.

The two-year extension means Cassini will make 60 additional orbits of Saturn, 26 of Titan, seven of Enceladus, including a swing to within as close as 24 kilometres (15 miles) of its surface, and one each of Dione, Rhea and Helene, ESA said.