It’s finally about to happen, the final violent end of NASA’s Cassini spacecraft as it plunges into the atmosphere of Saturn, ending a journey that began nearly 20 years ago. For the past 13 years, Cassini has been orbiting the gas giant and observing not only Saturn but its many intriguing moons.

But now, it’s running low on fuel, which means mission operators won’t be able to control the spacecraft when it runs out. So instead they’ve decided on “The Grand Finale,” a final mission that involves sending the $3.26 billion spacecraft between Saturn’s rings and then sending Cassini itself crashing into the planet on Sept. 15, less than a week away.

During this flight, Cassini will continue to gather and send information as long as it can keep its antennae pointed towards us here on Earth. And it will certainly go down in history as one of the most spacecraft that NASA has ever produced, providing more information on our solar system than just about any other.

“After two decades in space, NASA’s Cassini spacecraft is nearing the end of its remarkable journey of exploration,” NASA says on its website. “Having expended almost every bit of the rocket propellant it carried to Saturn, operators are deliberately plunging Cassini into the planet to ensure Saturn’s moons will remain pristine for future exploration—in particular, the ice-covered, ocean-bearing moon Enceladus, but also Titan, with its intriguing pre-biotic chemistry.

“Beginning in 2010, Cassini began a seven-year mission extension in which it completed many moon flybys while observing seasonal changes on Saturn and Titan. The plan for this phase of the mission was to expend all of the spacecraft’s propellant while exploring Saturn, ending with a plunge into the planet’s atmosphere. In April 2017, Cassini was placed on an impact course that unfolded over five months of daring dives—a series of 22 orbits that each pass between the planet and its rings. Called the Grand Finale, this final phase of the mission has brought unparalleled observations of the planet and its rings from closer than ever before.”