Hayabusa2 is a Japan Aerospace Exploration Agency (JAXA) led mission to study and sample asteroid 162173 Ryugu. As a primitive carbonaceous asteroid, investigations of Ryugu could address some important questions surrounding the very origins of our Solar System and how the materials necessary to form life (ices and organic compounds) may have originated. Hayabusa2 is a successor to the earlier 2010 JAXA Hayabusa mission which was the first mission to return samples from an asteroid.
Haybusa2 launched on the 3rd December 2014 and arrived at Ryugu on the 27th June 2018. It remained with the asteroid for around a year and a half, all the time taking images and undertaking analyses with its instrument suite. It made some fascinating discoveries such as: that Ryugu is covered with many large boulders over 10 m across; that Ryugu’s northern hemisphere is warmer than it’s southern hemisphere and that the temperature on Ryugu undergoes a ‘seasonal change’; and that the asteroids ‘abacus bead’ shape may have been formed by rapid rotation of the asteroid earlier in its history. A lot of remote sensing data was collected from Ryugu while Hayabusa2 was in close proximity and there will surely be many more interesting discoveries once scientists have sifted through it all!
Along with observing Haybusa2 from a distance, the instrument payload included 4 small rovers to be deployed to the surface to undertake more detailed observations. These rovers don’t resemble the large robotic Martian rovers we have all seen but are much smaller and look just like small cylinders covered in solar panels which provide their power. They were dropped to the surface from the Hayabusa2 spacecraft and once they landed undertook analyses using an instrument suite which included high-resolution cameras, temperature sensors and a gyroscope. The most interesting feature of these roves is that they could move around on the surface of Ryugu through ‘hopping’ by rotating an interior motor. These rovers were the very first man-made objects to explore movement on an asteroid surface.
One of the main objectives of the Hayabusa2 mission was to return primitive asteroidal material to Earth for study. The spacecraft used a special sampling mechanism to achieve this and sampled the surface twice before leaving Ryugu. The second sampling was especially exciting as prior to this the spacecraft had launched a projectile at the surface and created a ~15 m diameter crater. The second sample collection targeted material from within this crater, possibly sampling especially pristine material that has been buried and therefore not altered by the sometimes-harsh environment of space. This material could let scientists know how some of the most primitive materials in the solar system formed and what some of the most primitive isotopic signatures of our Solar System may have been.
Hayabusa2 left Ryugu in November 2019 and returned samples that were collected back on Earth on the 5th December 2020. Initial investigations upon opening the sample return capsule indicate that Hayabusa2 succeeded in its mission and has brought back lots of sample on which scientists can perform detailed analyses. As only the second instance of samples being returned to Earth from an asteroid I for one cannot wait to hear of all the discoveries that come about from investigating these fascinating samples.
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