Still from a video shows Cassini's last two Grand Finale orbits, followed by a distant flyby of Titan that pushes the spacecraft into Saturn. (Credit: NASA)

LOS ANGELES, Sept. 15 (Xinhua) -- After 13 years in orbit, the U.S. National Aeronautics and Space Administration (NASA)'s Cassini spacecraft made a fateful plunge into Saturn's atmosphere early Friday morning, ending the mission just one month shy of its 20th launch anniversary.

"Earth received @CassiniSaturn's final signal at 7:55 a.m. ET (1155 GMT). Cassini is now part of the planet it studied," Cassini's team said on Twitter Friday morning.

The probe was running low on fuel, so the 13-year tour of the Saturn system mission had to end.

The spacecraft made a deliberate plunge into Saturn's atmosphere to avoid the small possibility of it crashing into a potentially habitable moon, in particular Enceladus.

Launched in 1997, the 3.26-billion-U.S.-dollar Cassini-Huygens mission has been touring the Saturn system since arriving there in 2004.

The Huygens lander separated from Cassini and plopped down on the surface of Saturn's moon Titan shortly after the arrival.

The Cassini probe had been scheduled to study the Saturn system until 2008, but the mission was given two extensions that stretched its lifetime into 2017.

During its journey, Cassini has made numerous dramatic discoveries.