Hayabusa2, Japan's mission to Ryugu and other asteroids

Highlights

• Asteroids are leftover planet-building materials from the birth of our Solar System. Unlike Earth rocks shaped by eons of weathering and geologic activity, asteroids have remained largely unchanged, making them time capsules that can teach us about the origin and evolution of our Solar System.
• Hayabusa2 returned samples of asteroid Ryugu to Earth in December 2020. Scientists will study the samples with high-precision instruments that are currently too large and power-hungry to fly in space.
  
• After dropping off its Ryugu samples, Hayabusa2 embarked on an extended mission to study more asteroids. The spacecraft will fly past asteroid 2001 CC21 in 2026 and rendezvous with asteroid 1998 KY26 in 2031.

Why do we need Hayabusa2? 

Our Solar System is filled with countless asteroids, comets, and other small worlds left over from the disk of dust and gas that formed the planets 4.5 billion years ago.

On Earth, weather and geological processes constantly alter the surface, but asteroids like Ryugu have remained largely unchanged since their formation. Studying the ages and compositions of different types of asteroids gives scientists important clues about how our Solar System evolved.

Although modern spacecraft instruments can teach us a lot about other worlds, certain kinds of experiments can only be done on Earth. Japan's Hayabusa2 (はやぶさ2) spacecraft launched in 2014 on a mission to survey asteroid Ryugu and collect a surface sample for return to Earth. The samples, which returned to Earth in 2020, will allow scientists to pin a precise date on when the asteroid’s materials formed, and when Ryugu may have been heated due to collisions with other asteroids. 

Because Hayabusa2 is still healthy, Japan's space agency JAXA sent it on an extended mission to visit two more asteroids. The spacecraft will fly by asteroid 2001 CC21 once in 2026 and Earth two times in 2027 and 2028 before arriving at asteroid 1998 KY26 in 2031.

To assist with navigation around Ryugu, Hayabusa2 carried five baseball-like target markers it dropped to the surface. The markers contained names collected by The Planetary Society and JAXA in 2013. A copy of the names also flew to Ryugu and back inside the spacecraft's sample return container. You can search for your name via JAXA's website.

How Hayabusa2 works

Hayabusa2 is equipped with a variety of instruments that helped it study Ryugu, and will help it study asteroids during its extended mission. Key technologies include a laser altimeter to create 3D maps, a thermal imager to measure surface temperatures, and a spectrometer to determine the composition of surface minerals.

Hayabusa2 collected its samples from Ryugu using a meter-long sample horn extending from the bottom of the spacecraft. When the horn touched the surface, it fired a bullet-like projectile that kicked surface material up the horn into a collection bin. Later, Hayabusa2 transferred the bin into an Earth-return capsule that the spacecraft dropped into Earth's atmosphere for recovery in Australia in December 2020.

One of the samples Hayabusa2 collected came from an artificial crater the spacecraft created. SCI, the Small Carry-on Impactor experiment, fired a copper plate into the surface to expose fresh asteroid material for collection.

Hayabusa2 also deployed a series of rovers to study Ryugu up close. MASCOT, the Mobile Asteroid Surface Scout, carried a camera system, magnetometer, infrared microscope, and a radiometer. Hayabusa2 also carried three drum-shaped rovers named MINERVA, two of which successfully hopped around the surface.

Learn more

• Asteroids, comets, and other small worlds
• Every mission to an asteroid, comet, or small world ever
• Solar System timeline

Academic resources

• Yada, T., Abe, M., Okada, T., Nakato, A., Yogata, K., Miyazaki, A., Hatakeda, K., Kumagai, K., Nishimura, M., Hitomi, Y., Soejima, H., Yoshitake, M., Iwamae, A., Furuya, S., Uesugi, M., Karouji, Y., Usui, T., Hayashi, T., Yamamoto, D., … Tsuda, Y. (2021). Preliminary analysis of the Hayabusa2 samples returned from C-Type asteroid Ryugu. Nature Astronomy, 6(2), 214–220.

• Tsuda, Y., Yoshikawa, M., Saiki, T., Nakazawa, S., & Watanabe, S.-ichiro. (2019). Hayabusa2–sample return and Kinetic Impact Mission to near-earth asteroid Ryugu. Acta Astronautica, 156, 387–393.