The Cassini space orbiter is hours from oblivion as it hurtles toward Saturn's atmosphere, with scientists watching from Earth.
Scientists at US space agency NASA expect Cassini's final transmission to reach Earth about 1155 GMT on Friday (9:55 Saturday AEST), 83 minutes after the density of the giant gas planet's atmosphere is likely to cause the spacecraft to tumble, severing its radio signal.
The process will end quickly as friction with the atmosphere causes Cassini to burn up and disintegrate, much like a meteor.
The Cassini-Huygens mission, a co-operative project of NASA, the European Space Agency and the Italian Space Agency, was launched in 1997 and reached Saturn's orbit in 2004.
During more than 13 years circling Saturn, the Cassini orbiter explored Saturn's moon Enceladus and its ice crust.
The ESA-built Huygens probe travelled with Cassini and was dropped in 2005 onto Titan, another of Saturn's moons. The first close-up view of Titan revealed some Earth-like characteristics and influenced how scientists are looking for life in space.
Even during its final descent, Cassini is sending new data about Saturn's atmosphere back to Earth.