File photo: This illustration of NASA's Cassini spacecraft about to make one of its dives between Saturn and its innermost rings as part of the mission's grand finale. (Xinhua/REUTERS/NASA/JPL-Caltech)

LOS ANGELES, Aug. 29 (Xinhua) -- The U.S. National Aeronautics and Space Administration (NASA)'s Cassini spacecraft will make a mission-ending plunge into the atmosphere of Saturn on Sept. 15.

During the coming 18 days, the vehicle will pass several milestones en route to its science-rich Saturn plunge, the agency said Tuesday.

"The Cassini mission has been packed full of scientific firsts, and our unique planetary revelations will continue to the very end of the mission as Cassini becomes Saturn's first planetary probe, sampling Saturn's atmosphere up until the last second," Linda Spilker, Cassini project scientist from NASA's Jet Propulsion Laboratory (JPL), said in a statement.

The long-lived spacecraft's fateful plunge is a foregone conclusion -- an April 22 gravitational kick from Saturn's moon Titan placed the two-and-a-half ton vehicle on its path for impending destruction.

"We'll be sending data in near real time as we rush headlong into the atmosphere -- it's truly a first-of-its-kind event at Saturn," Spilker said.

After beginning its descent into Saturn's upper atmosphere, the spacecraft is expected to lose radio contact with Earth within about one to two minutes.

But on the way down, before contact is lost, eight of Cassini's 12 science instruments will be operating. In particular, the spacecraft's ion and neutral mass spectrometer (INMS), which will be directly sampling the atmosphere's composition, will be potentially returning insights into the giant planet's formation and evolution, according to NASA.

On Sept. 14, other Cassini instruments will make detailed, high-resolution observations of Saturn's auroras, temperature, and the vortices at the planet's poles.

Cassini's imaging camera will take a last look at the Saturn system on the day before the plunge and will be off during this final descent.

"The end of Cassini's mission will be a poignant moment, but a fitting and very necessary completion of an astonishing journey," said Earl Maize, Cassini project manager at NASA's JPL.

Launched in 1997, Cassini has been touring the Saturn system since arriving there in 2004. During its journey, Cassini has made numerous dramatic discoveries. But the mission is drawing near its end because the spacecraft is running low on fuel.