(CNN)NASA's Cassini probe has entered the final phase of its 13-year mission to Saturn, executing the first in a series of five "ultra-close" dives through the planet's atmosphere.
NASA's Cassini probe dives into Saturn's atmosphere
The spacecraft embarked on the first orbit on Sunday evening, marking a turning point in planetary exploration as Saturn's upper atmosphere has never previously been explored.
The probe's instruments are expected to collect rich scientific data as it makes the dives, potentially revealing how the planet is arranged internally and how much material is contained in its icy rings.
With the first pass still in progress, Cassini will go where no craft has gone before -- reaching as close as 1,010 and 1,060 miles (1,630 and 1,710 kilometers) above the planet's cloud tops.
"As it makes these five dips into Saturn, followed by its final plunge, Cassini will become the first Saturn atmospheric probe," Linda Spilker, a Cassini project scientist said in a statement.
"It's long been a goal in planetary exploration to send a dedicated probe into the atmosphere of Saturn, and we're laying the groundwork for future exploration with this first foray," Spilker said.
The spacecraft is equipped with rocket thrusters to remain stable when in contact with the atmosphere, in what NASA has dubbed the "Grand Finale" of the mission.
Launched in 1997, Cassini reached Saturn in 2004. The craft revolutionized scientists' knowledge of Saturn, with its first close-up survey of the gas giant.
The craft is now locked into a terminal collision course with the atmosphere of the planet, where it is expected to burn up like a meteor on September 15 at 9:45 a.m. GMT (6:45 a.m. ET).
Once the final five orbits are complete, Cassini will plunge towards Saturn, with seven instruments turned on and reporting real-time measurements before its thrusters fail against Saturn's atmosphere.
At this point, contact will be permanently lost and the spacecraft will burn up.
Experts say that allowing Cassini to be destroyed reduces the risk of the probe damaging one of Saturn's moons and impacting future scientific work.