Hayabusa2 image captured near the touchdown site roughly a minute after touchdown. The photograph was taken at roughly 80 feet (25 meters) with the Optical Navigation Camera – Wide angle (ONC-W1) on February 22, 2019 (JST).
Credit: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST

Japan’s Hayabusa2 made a successful first touchdown and sampling operation February 22, 2019 (JST) at asteroid Ryugu. Mission planners are moving forward with the next event – the experiment to form an artificial crater using the Small Carry-on Impactor (SCI).

Credit: JAXA

A second touchdown will be done inside or outside the artificial crater formed with the SCI. There is a high probability that a third touchdown will not be performed.

Sufficient sample collected

A Japan Aerospace Exploration Agency (JAXA) Hayabusa2 Project media briefing on March 5th reports that the first touchdown has been judged to have collected a “sufficient sample.”

During the first touchdown, some of the optical sensors in the spacecraft base received a reduced amount of light. There is no problem during normal operations, but this effect means that careful preliminary investigation is necessary ahead of touchdown operations. As this preparation takes time, the SCI operation will be performed first.

Credit: JAXA

 

After Hayabusa2 ascended following the touchdown, and checking the telemetry on the ground, it was confirmed from the status and temperature change of the projector that the spacecraft’s bullet-like projectile had indeed fired.

 

Touchdown point

A nickname for the spacecraft’s touchdown point has been selected: “Tamatebako.”

While not an official name it was the most popular suggestion when requesting names from Project Members. In the story of Urashima Taro (where Ryugu takes its name), smoke emerges from the tamatebako (treasure box) which is like the ejected asteroid material flying upwards at touchdown. Also because this is the point where the sample (= treasure of Ryugu) was collected.

Credit: JAXA

Initial impressions

Noted within the press briefing, scientific analysis is in progress, but the following describes initial impressions from imagery taken by Hayabusa2.

  • There seems to be an area containing a lot of debris/particle scattering / floating material just above Ryugu’s surface.
  • There also seems to be abrasions on the ground made with the sampling bullet and thruster firing.
  • A large quantity of scattered particles/debris can be seen: the potential for sample collection is high.
  • Fine particles may have adhered to the lens of the ONC-W1 camera.
  • The sampler horn seemed able to make contact with the ground without striking any large rocks.
  • Surface images are similar to those captured by the Hayabusa2-deployed landers: the surface is covered with rocks of average size about 10 centimeters.
  • After touchdown, rocks reaching sizes of several tens of centimeters in diameter were ejected.
  • Many chips of this released debris are flattened plate-shaped and appear to reach quite a high altitude.

Credit: JAXA

Credit: JAXA

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