A Japanese spacecraft has snagged a sample of dust from an asteroid zooming through space more than 151 million miles from Earth. It’s the second sample that this vehicle has grabbed from the asteroid, and it’s also the last one the probe will collect before heading back to Earth this fall.

The sample-gathering spacecraft is Hayabusa2, which is operated by the Japan Aerospace Exploration Agency (JAXA). Launched in 2014, the vehicle has been hovering around an asteroid named Ryugu since arriving at the object in June 2018. Its main goal is to grab small bits of rocks and dirt off of Ryugu to return to our planet where scientists can study these pieces in labs. Hayabusa2 could have easily been done when it grabbed its first sample in February, but the team behind the spacecraft decided to collect another sample before returning home. And this sample is much more tantalizing than the first one.

This sample was grabbed right next to a crater that Hayabusa2 made on Ryugu

This sample was grabbed right next to a crater that Hayabusa2 made on Ryugu. That’s right: the spacecraft blasted its own small hole in the asteroid in April. During that event, Hayabusa2 deployed what was essentially a tiny bomb over the surface of Ryugu where it burst apart and created a small impression in the rock. Then, on Wednesday night, the spacecraft collected a sample of rocks about 20 meters from where that artificial crater is located.

To snag its sample, Hayabusa2 is equipped with a bullet-like projectile attached to an appendage shaped like a horn. When the spacecraft gets close to the surface of the asteroid, it taps the end of the horn on the ground, and the bullet shoots out. The whole thing kicks up a cloud of dust that is supposed to go up into the horn and then into a collection chamber in Hayabusa2’s belly.

Scientists are pretty sure that this sample contains material from within Ryugu that was blasted outward when the bomb went off. That means some of the dust within the latest sample could have been buried underneath the surface of the asteroid for billions of years since the early days of the Solar System. Such materials are precious to researchers since these rocks have not been exposed to the harsh space environment or dealt with any space weathering. Those relatively pristine conditions mean that Hayabusa2’s latest sample may provide a nice snapshot of some of the materials that were around when our cosmic neighborhood first formed.

That’s a big deal for planetary scientists, as many experts believe that some of the basic building blocks of life on Earth came from asteroids bombarding our planet. Hayabusa2’s samples could hold important clues about what asteroids might have transported to Earth when it was still a newborn world.

Hayabusa2 likely has materials from two samples in its collection chamber, though researchers won’t know for sure until the spacecraft returns. Since there’s no way to measure what’s inside the chamber while it’s in space, it’s possible there’s nothing in there right now. However, Japanese researchers are confident that Hayabusa2 got materials on both sample grabs. Whatever it did snag will be small, though. JAXA is hoping to get about 100 milligrams of the sample from Ryugu.

Now, Hayabusa2’s time at the asteroid is nearing its end. The vehicle is slated to start its journey home in November or December with the goal of reaching Earth by the end of 2020. When it gets back to Earth, the spacecraft will deploy a capsule filled with samples toward Earth, which will reenter the planet’s atmosphere and parachute down to the ground below, touching down somewhere in the Australian desert.