US space agency NASA received the final signal from its Cassini spacecraft on Friday as its groundbreaking 13-year Saturn mission ended with a meteor-like plunge into the planet's atmosphere.

Cassini, the first spacecraft to orbit Saturn, ended its mission around 8.54pm AEST, shortly after it lost contact with Earth as it entered the gas giant's crushing atmosphere at about 113,000 km/hr.

"Our spacecraft has entered Saturn's atmosphere, and we have received its final transmission," NASA in a post on Twitter, via its official @CassiniSaturn profile.

The end of Cassini's odyssey, which began with its launch in 1997 and a seven-year journey to the ringed planet, was met with applause, hugs and tears from NASA officials after its final transmission was received.

Cassini's final transmissions are expected to include unprecedented data from the atmosphere's upper fringe about 1915 kilometres above Saturn's cloud tops. The data took 86 minutes to reach NASA antennas in Canberra.

"Not only do we have an environment that just is overwhelming with an abundance of scientific mysteries and puzzles, but we've had a spacecraft that's been able to exploit it," Earl Maize, Cassini project manager at NASA's Jet Propulsion Laboratory in Pasadena, California, said at a news briefing on Wednesday.

Seasonal changes

Cassini's final dive ended a mission that gave scientists a ringside seat to the sixth planet from the sun. The craft's discoveries included seasonal changes on Saturn, a hexagon-shaped pattern on the north pole and the moon Titan's resemblance to a primordial Earth.

Cassini also found a global ocean on the moon Enceladus, with ice plumes spouting from its surface. Enceladus has become a promising lead in the search for places where life could exist outside Earth.

The spacecraft has produced 450,000 images and 635 gigabytes of data since it began probing Saturn and its 62 known moons in July 2004.

Cassini is a cooperative project between NASA, the European Space Agency and the Italian Space Agency, and was launched into space in October 1997 from Cape Canaveral in Florida.

Since the spacecraft was running low on fuel, NASA crashed it into Saturn to avoid any chance the spacecraft could one day collide with and contaminate Titan, Enceladus or another moon that has the potential for indigenous microbial life.

Cassini started a series of 22 orbital dives in April, using Titan's gravity to slingshot itself into the unexplored area between the planet and its rings. The spacecraft studied Saturn's atmosphere and took measurements to determine the size of the planet's rocky core.

NASA scientists have said Cassini's final photo as it heads into Saturn's atmosphere will likely be of gaps in the rings caused by tiny moons.

Reuters