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MASCOT landing on Ryugu, 3 October 2018
Hungry4info
post Aug 25 2019, 03:28 AM
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There are some images from MASCOT at the following website, showing the area that we have seen before, but at four different times of day.
https://mascot.cnes.fr/fr/les-premieres-pho...yugu-par-mascot

At first I was having a hard time connecting surface features but then I realised that MASCOT moved a bit between the late morning and noon images. This is confirmed in the Science paper posted yesterday (23 August 2019).
QUOTE
On the morning of the third day, the lander slipped ~5 cm sideways by executing a mini-move to enable stereo imaging for photogrammetric analysis, reaching a third location (MP3)


I've constructed a 3D anaglyph and a black-and-forth .gif that shows the move, and the 3D perspective of the surface. The 3D image is kinda crude, admittedly.
(Edit: Added a cropped .gif that shows less, of course, but should help look less like a light-switch as that seems to mess with one's mind after a bit)
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Hungry4info
post Aug 25 2019, 04:10 AM
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Similar in theme to my last post. This animation blinks between the Noon image and the Late Afternoon image, showing differences in illumination angle. It looks like the lander has slid a bit between these two images as well, and I'm pretty confident it is not an artifact of the changes in lighting angle.
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Marcin600
post Aug 26 2019, 11:24 PM
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Beautiful photos!
This article is also interesting (22 August 2019) with a handful of photos from MASCOT, including this famous picture, which we all waited for. I took out a few of them (Credit: MASCOT / DLR / JAXA).

PS. In the article, informative descriptions are visible under the photos in the Fullscreen option
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Marcin600
post Aug 26 2019, 11:30 PM
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QUOTE (Hungry4info @ Aug 25 2019, 06:10 AM) *
Similar in theme to my last post. This animation blinks between the Noon image and the Late Afternoon image, showing differences in illumination angle. It looks like the lander has slid a bit between these two images as well, and I'm pretty confident it is not an artifact of the changes in lighting angle.


I think that in microgravity on Ryugu, every smallest movement of scientific instruments inside the lander generates small corps shifts


(„... at 10 kilograms, MASCOT experienced a gravitational force of 0.17 grams on Ryugu...”)
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Marcin600
post Aug 26 2019, 11:54 PM
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In the cited article there is also an interesting reference to the discussion about dust (or rather its lack) on the surface of Ryugu, which I initiated on this forum a few months ago:

"...Ralf Jaumann and his team were particularly surprised by the lack of dust: "Ryugu's entire surface is littered with boulders, but we have not discovered dust anywhere. It should be present, due to the bombardment of the asteroid by micrometeorites over billions of years, and their weathering effect. However, as the asteroid has very low gravity – only one-sixtieth of that experienced on Earth’s surface – the dust has either disappeared into cavities on the asteroid or has escaped into space. This gives an indication of the complex geophysical processes occurring on the surface of this small asteroid...”
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Marcin600
post Aug 27 2019, 12:08 AM
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And another quote from the same article is particularly interesting for metorite collectors:

"...Until now, the MASCOT scientists believed that Ryugu was similar to two meteorites that fell to Earth in 1969 in Allende, Mexico, and Murchison, Australia. However, those meteorites barely contain bright particles, probably due to the weathering effect of water in the crystal grid of these minerals. The bright inclusions that have now been observed have led the scientists to conclude that Ryugu's cauliflower-like rocks bear greater similarities to meteorites from Tagish Lake. On 18 January 2000, hundreds of small meteorites rained down on Earth following the explosion of a large fireball over Canada, and numerous fragments were found on the ice of the frozen lake.

These are very rare stony meteorites from what is referred to as the CI chondrite class. The C stands for the chemical element carbon, and the I for the similarity with the Ivuna meteorite found in Tanzania. They are among the oldest and most primitive components of the Solar System, remnants of the first solid bodies to be formed in the primordial solar nebula..."
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Marcin600
post Aug 27 2019, 12:46 AM
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I added the scale bar according to the original description under the color picture
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Marcin600
post Aug 27 2019, 01:05 AM
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A little play with a changing perspective in this crazy but beautiful world
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Marcin600
post Aug 27 2019, 01:23 AM
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QUOTE (Marcin600 @ Aug 27 2019, 02:46 AM) *
I added the scale bar according to the original description under the color picture




I'm afraid, however, that my scale bar is incorrect!!!

Does anyone know how to calculate it correctly?
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Marcin600
post Aug 27 2019, 01:33 AM
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I just found the right reference

Now the scale is OK rolleyes.gif

Sorry about that!
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Marcin600
post Aug 27 2019, 01:53 AM
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And yet only a larger version (b/w) of the night picture of the surface of Ryugu (from here )
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Marcin600
post Nov 16 2019, 08:20 PM
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I am not sure if the color night picture of the Ryugu's surface appeared here in such resolution ( from here ):
(I'm sorry if I repeat myself, but such pictures do not stop to fascinate me - from an anonymous dot of light to the New World)

Credit: MASCOT/DLR/JAXA
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Paolo
post Dec 6 2019, 10:30 AM
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the latest issue of Astronomy & Astrophysics has three papers (in free access!) on MASCOT:

The descent and bouncing path of the Hayabusa2 lander MASCOT at asteroid (162173) Ryugu
QUOTE
Images from the Optical Navigation Camera system (ONC) onboard the Hayabusa2 spacecraft show the MASCOT lander during its descent to the surface of asteroid (162173) Ryugu. We used results from a previous stereo-photogrammetric analysis that provided precise ONC image orientation data (camera position and pointing), ONC orthoimages, and an ONC-based 3D surface model to combine them with the visibilities of MASCOT itself and its shadow on-ground within the ONC images. We integrated additional information from instruments onboard MASCOT (MASMag, MARA, MASCam) and derived MASCOT’s release position and modeled its free-fall descent path and its velocity over 350 s from its release at ∼41 m altitude above ground until its first contact with the surface of Ryugu. After first contact, MASCOT bounced over the surface of Ryugu for 663 s and came to rest at its first settlement point after four intermediate surface contacts. We again used ONC images that show MASCOT and partly its shadow and reconstructed the bouncing path and the respective velocities of MASCOT. The achieved accuracy for the entire descent and bouncing path is ∼0.1 m (1σ).


The MASCOT landing area on asteroid (162173) Ryugu: Stereo-photogrammetric analysis using images of the ONC onboard the Hayabusa2 spacecraft
QUOTE
A high-resolution 3D surface model, map-projected to a digital terrain model (DTM), and precisely ortho-rectified context images (orthoimages) of MASCOT landing site area are important data sets for the scientific analysis of relevant data that have been acquired with MASCOT’s image camera system MASCam and other instruments (e.g., the radiometer MARA and the magnetometer MASMag). We performed a stereo-photogrammetric (SPG) analysis of 1050 images acquired from the Hayabusa2 Optical Navigation Camera system (ONC) during the asteroid characterization phase and the MASCOT release phase in early October 2018 to construct a photogrammetric control point network of asteroid (162173) Ryugu. We validated existing rotational parameters for Ryugu and improved the camera orientation (position and pointing) of the ONC images to decimeter accuracy using SPG bundle block adjustment. We produced a high-resolution DTM of the entire MASCOT landing site area. Finally, based on this DTM, a set of orthoimages from the highest-resolution ONC images around MASCOT’s final rest position complements the results of this analysis.


The Hayabusa2 lander MASCOT on the surface of asteroid (162173) Ryugu – Stereo-photogrammetric analysis of MASCam image data
QUOTE
After its release and a descent and bouncing phase, the Hayabusa2 lander MASCOT came to a final rest and MASCOT’s camera MASCam acquired a set of images of the surface of Ryugu. With MASCam’s instantaneous field of view of about 1 mrad, the images provide pixel scales from 0.2 to 0.5 mm pixel−1 in the foreground and up to 1 cm pixel−1 for surface parts in the background. Using a stereo-photogrammetric analysis of the MASCam images taken from slightly different positions due to commanded and unintentional movements of the MASCOT lander, we were able to determine the orientation for the different measurement positions. Furthermore, we derived a 3D surface model of MASCOT’s vicinity. Although the conditions for 3D stereo processing were poor due to very small stereo angles, the derived 3D model has about 0.5 cm accuracy in the foreground at 20 cm distance and about 1.5 cm at a distance of 40–50 cm.
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