During the second touchdown rehearsal (TD1-R1-A), we captured a sequential set of images as the spacecraft reached the point of lowest altitude and then began to rise (Figure 1). The spacecraft reached the lowest altitude of 22.3m above the surface of Ryugu on October 15, 2018 at 22:44 JST.

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  [open in another window] (mp4, 3.5MB) (Animated GIF, 38MB) Figure 1: Sequential images of Ryugu captured by the Optical Navigation Camera – Wide angle (ONC-W1). The images were taken on October 15, 2018 between 22:45 ~ 22:53 JST. The altitude of the spacecraft when the first image was taken is about 240m, the lowest altitude image is at about 47m at 22:45 JST and the altitude in the final image is about 370m.
  (Image credit ※: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST.)

The most promising candidate site for touchdown is L08-B and is also captured in these images (Figure 2). As you can see in Figure 2 and Figure 1, there are not any large boulders in L08-B, but there is a big cliff-like boulder in the upper right of Figure 2 so care is still needed.

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  [open in another window] Figure 2: Image of the surface of Ryugu captured with the ONC-W1 at an altitude of about 47m. The image was taken on October 15, 2018 at 22:45 JST. The red circle indicates the candidate point for touchdown, L08-B.
  (Image credit ※: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST.)

In the future, these images obtained during the rehearsals will be analyzed in more detail to aim for a safe touchdown.

Note

If you enlarge the shadow of the probe shown in Figure 2, you will see the following figure. The gap between the panels of the solar paddle is easily visible, as is the shape of the spacecraft and the two star trackers.

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  Figure 3: Enlargement of the shadow of the spacecraft.
  (Image credit ※: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST.)

Hayabusa2 project
2018.10.26