Mission: Hayabusa 2 Options

[alan]

Now in 3D

https://twitter.com/moffmiyazaki/status/1121635270946775040

[Marcin600]

The Crater:

https://twitter.com/haya2e_jaxa/status/1121381085957509120

According to this JAXA tweet above: „...The exact size and shape of the artificial crater will be examined in detail in the future, but we can see that terrain of an area about 20m wide has changed...”

But according to this source : „...As a result of Hayabusa 2 observation from a height of 1.7 km from Ryugu, it was found that the topography was deformed like a hole over a diameter of 10 meters...”

So, the crater has a diameter of between 10 and 20 m.

It seems to me that in the left and upper part we can see something like a low crater wall (?). The lower and the right part of the crater (in the picture) was disturbed by the presence of large stones

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[elakdawalla]

I interpret that pair of remarks to mean that the crater diameter is about 10 m, with visible surface changes (ejecta or the opposite, a removal of dust) over a diameter of 20 m.

[JTN]

The English translation of the press conference slides from April 11 (not including the recent crater search images) is now up on the material page.

[Marcin600]

A new press conference is scheduled for May 9, 15:00 JST = 6:00 UTC http://fanfun.jaxa.jp/jaxatv/detail/14553.html

"...At this briefing session we will explain crater search operations conducted from April 23 to 25 and the prospects for future exploration activities based on crater search operations..."

Maybe we will learn more details (and photos ) about the crater and some preliminary conclusions from this very interesting experiment!

[pandaneko]

Apparently, according to a local newspaper here, there are 11 craters made, minimum is 6 m in diamter,
largest 12 m, a target marker will be dropped on 16th and there will be a few observation decent
down to 10 m, then landing is planned for late next month before the asteroid gets too hot.

P

[Marcin600]

Press conference slides PDF (in Japanese): http://fanfun.jaxa.jp/jaxatv/files/20190509_hayabusa2.pdf

[Marcin600]

Google translation of press conference pdf - page 17:

"Science of SCI collision experiment: Summary

• SCI collision to S01 area (about 25 m distance) was successful.

• Impact emission (ejector) was observed for several hundred seconds (image taken by DCAM3).
– In low gravity, the duration is longer (about 300 times above the ground).
– Ejector deposition in the S01 area is strongly suggested.

• A nearly circular landform change exceeding 10 m in diameter was identified (ONC-T image).
-Drilling crater shape: Depth about 2-3 m. Side wall surface looks smooth.
-Movement of rock mass (digging) and accompanying topography change can also be seen.
– Changes in surface reflectivity (darkening) can also be observed (verification required).
-It is possible to estimate the surface strength and surface age of Ryugu from the diameter (next page).

• The formation of secondary craters and movement of rock mass can be seen along the oval circumference * .
– It is presumed that it is due to the collision of fragments (forward fragments) scattered forward of SCI.

* Precisely, "the line of intersection of the front piece cone and the long surface at the apex of the SCI operating point"

[Marcin600]

Page 20:

"4. Future operation policy:
■ Concept of operation plan from May to July
• Currently, Ryugu is approaching the sun (perihelion is in September). Asteroid surface temperature is high from now on It is possible to land until the beginning of July.
• The terrain around the crater and the condition of the spacecraft have been scrutinized by the beginning of June, and in fact the end of June Decide whether to implement touchdown operation at the beginning of July.
• The target point for implementation is the location where there is an ejector (scattered material) from an artificial crater
Choose from the area. • The operation name is “Pinpoint Touchdown” (PPTD).
• Two or three low altitude descent observation operations will be implemented between May and June before PPTD operation.
in addition
To conduct detailed topographical observation of the landing candidate site and, depending on the situation, drop the target marker.
• First run: 5/14 to 5/16, Operation name: PPTD-TM1 (described later)
• Second time: the end of May, Operation name: To be determined
• Third time: First half of June, Operation name: To be determined"

[Marcin600]

And my unauthorized translation (via Google translator) of four pages: 10, 13, 15 and 16 from press conference pdf :

[fragment of press conference video showing the SCI test and formation of additional craters - 29:22 - 29:55]

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[Marcin600]

my animated gif from JAXA press conference pdf (page 11)

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[Marcin600]

my animated gif's from JAXA press conference pdf - pages 31 and 30:

"SCI collision area taken from home position with ONC-T:
- Before SCI collision - 2019-03-21 13:03 (Japan time) altitude 14 km
- After SCI collision - 2019-04-17 21:04 (Japan time), Altitude 19 km
- After SCI collision (explanatory diagram)"

(Image credit: JAXA, Tokyo University, Kochi University, Rikkyo University, Nagoya University, Chiba Inst. Of Tech., Meiji Univ., Aizu Univ., AIST)

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[Marcin600]

and my animated gif from JAXA press conference pdf - page 14 [actually from press conference video - 25:34 - 27:13]

"Science of SCI collision experiment: Additional craters
Before and after the collision
Blink image for before and after comparison
Change is seen.
- Crater shape terrain formation (upper circle)
- Movement of rock mass (lower circle)"

(Image credit: JAXA, Tokyo University, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, Aizu University, AIST).

[my note: I think that according to JAXA scientists these "secondary" craters were created as a result of impacts of debris from the SCI detonation in space. That's why we can not actually call them secondary craters]

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[Marcin600]

Official English version of the 9 May press conference pdf is now available on Hayabusa2 site

Craters that I called "additional" in my previous posts were actually named "sub-craters".

And there is an interesting article on the Hayabusa2 website: "The western bulge of 162173 Ryugu formed as a result of rotationally driven deformation process"

[Nota bene: the first picture in this article above reminds me of my annotation to the photo of Ryugu, which I made last year in my post - blocked as suggesting a conspiracy theory Life is hard...]

[Marcin600]

PPTD-TM1 (Pinpoint Touchdown – Target Marker 1) operation is now in progress . The goal is to drop the marker near the new crater for a possible second landing (but: "...the decision to perform a second touchdown has not been finalized..."). The lowest point above the surface - 10 m - is to be reached on May 16, 11:58 JST = 02:58 UTC. So, there is a chance that we will see more detailed pictures of "the Crater"