For the first time ever, scientists are in the process of getting their hands on asteroid debris so old that it may contain clues about how our solar system was formed and how water got to Earth.
A capsule with two smudges of dirt from the asteroid Ryugu arrived in Japan on December 7, where researchers finally have the opportunity to measure how much has been collected. The aim of the Japanese Hayabusa2 mission was to collect at least 100 milligrams of surface and subsurface material and send it back to Earth.
“Hayabusa2 is at home,” said project manager Yuichi Tsuda of Japan’s Aerospace Exploration Agency (JAXA) at a press conference on December 6th, hours after the sample recovery capsule successfully landed in Woomera, Australia. “We have collected the treasure chest.”
Ryugu is an ancient, high-carbon asteroid with the texture of freeze-dried coffee (SN: 3/16/20). Planetary researchers believe it contains some of the earliest solids to form in the solar system, making it a time capsule in solar system history.
Hayabusa2 explored Ryugu from June 2018 to November 2019 and took two samples of the asteroid (SN: 02/22/19). One came from an artificial crater that Hayabusa2 shot into the surface of the asteroid and gave the spaceship access to the interior of the asteroid (SN: 04/05/19). On December 4, the spaceship released the sample return capsule from a height of about 220,000 kilometers above the earth’s surface. The capsule created a brilliant ball of fire as it roamed the Earth’s atmosphere.
In a “Quick Look Facility” in Woomera, gases that the asteroid material may have emitted were first analyzed. However, the capsule will only be opened after it reaches the JAXA center in Sagamihara, Japan.
Hayabusa2 is the second mission in which an asteroid sample is successfully returned to Earth. The first Hayabusa mission visited the stony asteroid Itokawa and returned to Earth in 2010. Due to technical and logistical problems, his return was years later than planned and only 1,534 grains of asteroid material (SN: 06/14/10).
For Hayabusa2, however, everything seems to have gone according to plan. The spaceship itself still has enough fuel to visit another asteroid, 1998 KY26, which is smaller and spinning faster than Ryugu. It examines how such asteroids could have formed, how they stick together and what could happen if one collided with Earth. The spacecraft will reach this asteroid in July 2031, although it will no longer take any more samples.