The Hayabusa2 spacecraft has quickly tapped the surface of asteroid Ryugu, making the first of three planned attempts to grab a pinch of dust. Analysis of the sample could shed light on the origins of planets or even on the possibility of life elsewhere in the solar system.
But scientists won’t know for sure how much dust Hayabusa2 succeeded in grabbing until the craft returns to Earth in 2020.
When Hayabusa2 arrived at the 1,000-meter-wide Ryugu in June, scientists were surprised to find the diamond-shaped asteroid’s surface covered with boulders (SN Online: 6/27/18). That rough terrain made finding a good landing spot difficult.
In December, the team performed experiments on Earth to make sure their sample collection technique would work on such a rocky surface. The tests suggested that the strategy, firing a tantalum bullet into the surface to kick up asteroid dust and then gathering that dust in a long flared horn, should work on Ryugu.
Scientists in the Japan Aerospace Exploration Agency’s control room in Sagamihara received data from Hayabusa2 just before 6 p.m. EST on February 21 (8 a.m. February 22 in Japan), confirming that the craft had safely touched down on Ryugu.
The mission team cheered, with one member yelling “Yatta!” — or “We did it!” in Japanese — according to video released by the Japanese space agency.
Shortly after, the team confirmed the spacecraft had successfully fired the bullet, which means it probably also collected a sample. The craft then rose from the surface and retreated to a safe distance from Ryugu.
“I just want to jump,” project manager Junichiro Kawaguchi said in an interview from the control room. “This was the most crucial point, whether you can confirm that the projectile has fired.”
Hayabusa2 has two more bullets on board for two more collection attempts later this year. For one sample, the team will use a larger projectile to blast a crater into the asteroid and get material from below the surface.
When the spacecraft returns to Earth, scientists will examine the samples for signs of organic material that could help explain how life got started in the solar system (SN: 1/19/19, p. 20).