After spending six years in space, a Japanese spacecraft has just landed in the desert of South Australia, bringing a small cache of asteroid rocks to Earth’s surface. It is only the second time in history that material from an asteroid has been returned to our planet. Ultimately, scientists will open the spacecraft and reveal the precious rocks inside to learn more about the asteroids that permeate our solar system.
The landing is the culmination of Japan’s Hayabusa 2 mission, which aims to return samples from an asteroid to Earth. After its launch from Japan in 2014, the Hayabusa2 spacecraft spent four years on a journey to an asteroid named Ryugu. The spacecraft spent a year and a half hanging around the asteroid, mapping the surface of the rock and sampling the material before returning to Earth.
Scientists are eager to see the rocks that returned Hayabusa 2, as original samples from an asteroid can tell us a lot about what our solar system looked like when the planets were first forming. That’s because asteroids are a bit like children’s pictures of our cosmic melodies. These space rocks have been around since the dawn of the solar system, and scientists believe that asteroids haven’t changed much over the past 4.6 billion years. These organisms contain many of the same materials that were present when the solar system was born, so studying these rocks in laboratories here on Earth can provide a key context about the early days of the planets.
The capsule will be transported to Japan, where we will learn how much asteroid material the mission has collected. The Japan Aerospace Exploration Agency (JAXA), which is overseeing the mission, hoped to return 100 milligrams of material from Ryugu, but the scientists had no way to measure the amount of sample Hayabusa2 collected while in space. Exactly this amount will be revealed upon the opening of the spacecraft in Japan.
Hayabusa2 used some creative techniques in collecting its samples in Ryugu. Equipped with a small, horn-shaped arm, the spacecraft first exploited the asteroid with this accessory in February of 2019. When the arm touched, it fired a bullet-like shell that penetrated the asteroid, spewing out a whole mess of dust and gravel that we hope will ascend into the century.
The spacecraft did not make a single sample from Ryugu. Hayabusa2 attempted this maneuver again in July of 2019, but the spacecraft did some excavation first. Before tapping the asteroid for a second time, the spacecraft dropped a canister of explosives on Ryugu, causing a crater on the asteroid to explode and exposing some rocks just below the surface. Hayabusa2 then clicked the surface inside this hole to capture some of this newly exposed material. The goal was to collect more pure rocks from Ryugu. The materials beneath the asteroid’s surface have not been exposed to the harsh space environment for billions of years like the rocks on the outer surface, which have likely experienced some changes and reactions over time. So the material from the crater could provide a better snapshot of the material that was present when the Solar System first formed.
Once the Hayabusa2 team felt confident that they had snatched enough Ryugu, the spacecraft left the asteroid in November of 2019. After spending the past year traveling to Earth, the spacecraft deployed a small capsule late Friday night, with samples of Ryugu inside. Then the capsule blasted off its path to Earth, and sank into 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 it could land gently in the Woomera restricted area in South Australia.
After hitting the ground, teams from JAXA did an extensive search in Australia to find the capsule. The car fell over an area of 100 square kilometers, or about 38 square miles. It also landed at night in Australia, which made the capsule even more difficult to discover. Fortunately, the capsule was equipped with a radio beacon that helped the teams determine where the spacecraft landed. Prior to landing, JAXA teams had set up five antennas around the expected landing site to help find the signal, and the agency also had a helicopter with a beacon receiver to help narrow the search. A drone was also on hand to fly over the area to take pictures.
Hayabusa2 is Japan’s second mission to retrieve samples from an asteroid. Its first mission, Hayabusa, brought asteroid samples back to Earth in 2010, although the mission only managed to collect tiny grains of asteroid material. We hope Hayabusa2 brings together more than the original Hayabusa offerings. And in 2023, NASA’s OSIRIS-REx mission is expected to return the largest sample of asteroid material ever collected.
Although Hayabusa2 has completed its primary mission, the spacecraft is far from finished. The main spacecraft is still in space and has just set off on a mission to visit another asteroid called 1998 KY26. Hayabusa2 will take 11 years to reach its new goal, with the goal of analyzing the space rock and learning more about asteroids orbiting us in space.
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