The Cassini space probe has just began its final phase of its Saturn mission, beginning the first of five extremely close passes of the gas giant as it prepares to make its final plunge into the planet. The spacecraft will come close enough to brush the very top of the Saturn atmosphere, and scientists hope it will provide unprecedented data about Saturn’s chemical composition.

Cassini is expected to make its final maneuver next month when it will plunge into Saturn’s hostile atmosphere, ending its life. It is currently flying in a series of loops around Saturn that are between the planet and its iconic rings. The spacecraft came within 1,000 miles from the cloud tops on Monday.

Scientists think that Saturn is mostly made up of hydrogen at 75 percent, with the rest being helium with some trace elements mixed in.

“It’s expected that the heavier helium is sinking down,” Nicolas Altobelli, the European Space Agency’s Cassini project scientist, told BBC News. “Saturn radiates more energy than it’s absorbing from the Sun, meaning there’s gravitational energy which is being lost. And so getting a precise measure of the hydrogen and helium in the upper layers sets a constraint on the overall distribution of the material in the interior.”

NASA said in a statement: “NASA’s Cassini spacecraft will enter new territory in its final mission phase, the Grand Finale, as it prepares to embark on a set of ultra-close passes through Saturn’s upper atmosphere with its final five orbits around the planet. Cassini will make the first of these five passes over Saturn at 12:22 a.m. EDT Monday, Aug. 14. The spacecraft’s point of closest approach to Saturn during these passes will be between about 1,010 and 1,060 miles (1,630 and 1,710 kilometers) above Saturn’s cloud tops.”