Japan’s asteroid sample return mission lands in Australian desert

• December 5, 2020

After spending six years in space, a Japanese spacecraft just landed in the desert of southern Australia, bringing a small cache of asteroid rocks to the surface of Earth. It’s only the second time in history that materials from an asteroid have been returned to our planet. Eventually, scientists will open the spacecraft up, uncovering the precious rocks within to learn more about the asteroids that permeate our Solar System.

The landing is the culmination of Japan’s Hayabusa2 mission, aimed at bringing samples of an asteroid back to Earth. After launching from Japan in 2014, the Hayabusa2 spacecraft spent four years journeying to an asteroid named Ryugu. The vehicle spent a year and a half hanging around the asteroid, mapping the rock’s surface and grabbing samples of material before heading back to Earth.

Scientists are eager to see the rocks that Hayabusa2 has returned, as pristine samples from an asteroid could tell us a lot more about what our Solar System was like when the planets were first forming. That’s because asteroids are a bit like baby pictures of our cosmic neighborhood. These space rocks have been around since the dawn of the Solar System, and scientists believe asteroids haven’t really changed much over the last 4.6 billion years. These objects contain many of the same materials that were present at the Solar System’s birth, so studying these rocks in labs here on Earth could provide key context about the early days of the planets.

Photo by STR/JIJI PRESS/AFP via Getty Images

The capsule will be transported to Japan, where we’ll learn how much asteroid material the mission gathered. The Japanese Aerospace Exploration Agency (JAXA), which oversees the mission, hoped to bring back 100 milligrams of material from Ryugu, but scientists didn’t have a way to measure how much sample Hayabusa2 had collected while in space. That exact amount will be revealed when the spacecraft is opened in Japan.

Hayabusa2 used some creative techniques for collecting its samples at Ryugu. Equipped with a small horn-shaped arm, the spacecraft first tapped the asteroid with this appendage in February of 2019. When the arm made contact, it shot out a bullet-like projectile that punctured the asteroid, releasing a whole mess of dust and pebbles that hopefully went up into the horn.

The spacecraft didn’t just make one sample grab at Ryugu, though. Hayabusa2 tried this maneuver again in July of 2019, but the spacecraft had done a bit of excavating first. Before tapping the asteroid a second time, the spacecraft dropped a can of explosives onto Ryugu, blasting a crater on the asteroid and revealing some of the rocks located just below the surface. Hayabusa2 then tapped the surface inside this crater to scoop up some of this newly exposed material. The goal was to gather even more pristine rocks from Ryugu. The material underneath the asteroid’s surface hasn’t been exposed to the harsh environment of space for billions of years like the rocks on the exterior, which have likely experienced some change and reactions over time. So the material from the crater could provide an even better snapshot of the materials that were present when the Solar System first formed.

Image: DLR

Once the Hayabusa2 team felt confident they had grabbed enough from Ryugu, the spacecraft left the asteroid in November of 2019. After spending the last year traveling to Earth, the spacecraft deployed a small capsule late Friday night, with the samples of Ryugu located inside. The capsule then set on a course for Earth, plunging through our planet’s atmosphere this morning. It then deployed a parachute, slowing the vehicle from about 12 kilometers per second, or nearly 27,000 miles per hour, so that it could land gently in the Woomera Prohibited Area in southern Australia.

After it hit the ground teams from JAXA went on an extended search in Australia to find the capsule. The vehicle came down in an area that covers 100 square kilometers, or around 38 square miles. It also landed at nighttime in Australia, making the capsule even more difficult to spot. Fortunately, the capsule was equipped with a radio beacon that helped teams locate where the spacecraft touched down. Before the landing, JAXA teams set up five antennas around the expected landing site to help find the signal, and the agency also had a helicopter with its own beacon receiver to help narrow down the search. A drone was also on hand to fly overhead of the area to take pictures.

Hayabusa2 is Japan’s second mission to retrieve samples of an asteroid. Its first mission, Hayabusa, returned asteroid samples to Earth in 2010, though the mission only managed to collect tiny grains of asteroid material. Hayabusa2 will hopefully have collected even more than the original Hayabusa’s offerings. And in 2023, NASA’s OSIRIS-REx mission is expected to return the largest sample of material from an asteroid ever collected.

Though Hayabusa2 has completed its primary mission, the spacecraft isn’t quite done yet. The main spacecraft is still in space and just set out on a quest to visit another asteroid called 1998 KY26. It’ll take Hayabusa2 11 years to reach its new target, with the goal of analyzing the space rock and learning even more about the asteroids that zoom around us in space.

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After spending six years in space, a Japanese spacecraft just landed in the desert of southern Australia, bringing a small cache of asteroid rocks to the surface of Earth. It’s only the second time in history that materials from an asteroid have been returned to our planet. Eventually, scientists will…