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Unmanned Spaceflight.com _ Hayabusa2 _ MASCOT landing on Ryugu

Posted by: Hungry4info Oct 2 2018, 04:07 AM

The Japanese Hayabusa 2 twitter account reports that the spacecraft has begun descending toward Ryugu in preparation to deploy the MASCOT lander. Nothing on the English twitter as of the time of this post.
https://twitter.com/haya2_jaxa/status/1046965970466746369

Posted by: yoichi Oct 2 2018, 06:00 AM

QUOTE (Hungry4info @ Oct 2 2018, 01:07 PM) *
The Japanese Hayabusa 2 twitter account reports that the spacecraft has begun descending toward Ryugu in preparation to deploy the MASCOT lander. Nothing on the English twitter as of the time of this post.
https://twitter.com/haya2_jaxa/status/1046965970466746369


English twitter account of HAYABUSA 2.
https://twitter.com/haya2e_jaxa


Posted by: xflare Oct 2 2018, 06:12 AM

And the realtime images are back http://www.hayabusa2.jaxa.jp/en/galleries/onc/nav20181002/

Posted by: mcmcmc Oct 2 2018, 12:02 PM

Follow #Hayabusa2 approach to #Ryugu for #MASCOT delivery in realtime!
https://programmi.000webhostapp.com/hayabusa2/simulator/simulator.html

Altitude logs:
http://win98.altervista.org/hayabusa2/simulator/hayabusa2.txt
https://programmi.000webhostapp.com/hayabusa2/simulator/ONC_A-log.txt

 

Posted by: mcmcmc Oct 2 2018, 03:39 PM

QUOTE (mcmcmc @ Oct 2 2018, 12:02 PM) *
Follow #Hayabusa2 approach to #Ryugu for #MASCOT delivery in realtime!
https://programmi.000webhostapp.com/hayabusa2/simulator/simulator.html

Altitude logs:
http://win98.altervista.org/hayabusa2/simulator/hayabusa2.txt
https://programmi.000webhostapp.com/hayabusa2/simulator/ONC_A-log.txt


It appears from the simulator that from 1500 meters on, MINERVA rovers will start to be visible as 1 pixel bright objects in ONC-T. But we'll have to wait down to 400 meters to see them in ONC-W.
ONC-T resolution is 10 times ONC-W, so 1 pixel in ONC-W is 10 pixel in ONC-T.

Posted by: nprev Oct 3 2018, 12:19 AM

Spaceflight Now providing live coverage of MASCOT's landing https://spaceflightnow.com/2018/10/02/mascot-landing-mission-status-center/.

Posted by: Hungry4info Oct 3 2018, 01:39 AM

The last three frames show a persistent very bright dot on the surface. Possible MINERVA-II1 rover or protective drum?



 

Posted by: Phil Stooke Oct 3 2018, 02:22 AM

Sorry, no - the Minerva area is on the other side of Ryugu. The white spot might be added to the images to indicate the descent target point (I'm only guessing) or it could be a naturally reflective object (there are several of them in earlier images). When somebody posted about the sizes of Minerva hardware in pixels, I think they were really only talking about image resolution, not whether the items would be visible, because they are not near the Masot landing area. For one thing, Mascot is targeted south of the equatorial ridge, Minerva was targeted north of it.

Phil

Posted by: neo56 Oct 3 2018, 03:04 AM

Identification of some rocks on photos taken by Hayabusa2 on 2018/10/03 at 00h41 and 01h12 UTC with estimated position of Hayabusa2 shadow




Posted by: nprev Oct 3 2018, 03:15 AM

Separation confirmed per Spaceflight Now!

Posted by: MahFL Oct 3 2018, 03:25 AM

QUOTE (nprev @ Oct 3 2018, 04:15 AM) *
Separation confirmed per Spaceflight Now!


Tweet confirms it.

Posted by: neo56 Oct 3 2018, 04:15 AM

Identification of rocks on the picture taken at 1h46 UTC with shadow of Hayabusa 2 as a red cross. The shadow is probably shifted out of the map on the right since the map is missing a vertical band of latitude on 340° and 360°.


Posted by: mcmcmc Oct 3 2018, 07:48 AM

My recording of the delivery operations based onhttp://haya2now.jp/en.html (altitude in meters):

CODE
Alt    Generated at (GMT)     Received At (GMT))
101    2018-10-03 01:47:38    2018-10-03 02:05:47
47    2018-10-03 01:58:18    2018-10-03 02:16:27 - Mimimum altitude for 4 minutes
134    2018-10-03 02:02:02    2018-10-03 02:20:10 - Hayabusa 2 rises again.


Full recording of descent:
https://programmi.000webhostapp.com/hayabusa2/simulator/ONC_A-log.txt

There are multiple lines for same data, but if you set up a "sparse data" chart in Excel, multiple lines will result is same point be drawn at same coordinate, so you'll just see one point.

Press conference video (no links to press release yet):
https://www.youtube.com/watch?v=O3WNAg5Zfvs

It looks like national broadcasting company NHK created a simulated realtime video based on JAXA data during descent, but it was live, and I can't find the recording now:
http://www.nhk.or.jp/special/space/#/english

Posted by: Adam Hurcewicz Oct 3 2018, 07:58 AM

Now starts video brief in DLR Youtube channel

https://m.youtube.com/watch?v=axqedwOW-jo

Posted by: neo56 Oct 3 2018, 08:43 AM

First image of MASCOT released, showing the landing site from an altitude of 40m:


Posted by: mcmcmc Oct 3 2018, 08:48 AM

image!

https://twitter.com/MASCOT2018/status/1047406828617965568

Posted by: neo56 Oct 3 2018, 08:48 AM

JAXA just released the picture on its MASCOT lander feed: we even see the shadow of MASCOT ohmy.gif



Posted by: mcmcmc Oct 3 2018, 09:02 AM

QUOTE (neo56 @ Oct 3 2018, 08:48 AM) *
JAXA just released the picture on its MASCOT lander feed: we even see the shadow of MASCOT ohmy.gif



Released where? I found this image, but 180° rotated, on MASCOT2018 Twitter feed.

Posted by: Gerald Oct 3 2018, 11:33 AM

https://www.youtube.com/watch?v=axqedwOW-jo&app=desktop.
There will be two more updates in 2 resp. 4 hours from now.

Posted by: Gerald Oct 3 2018, 11:36 AM

Mascot is fine after initial issues.
Performing night sequences, all instruments are working.

Posted by: Gerald Oct 3 2018, 01:46 PM

"short delay - stay tuned"

Posted by: Weywot Oct 3 2018, 01:47 PM

https://twitter.com/MASCOT2018/status/1047456139024261121

The team seems very confident in the hopping and uprighting mechanism. The found the first landung spot too dark and unstable, so commanded a first hop at the beginning of the first sol, to begin the science sequence at another location.

Next press conference has a delay but should beginn soon.

Posted by: Gerald Oct 3 2018, 01:57 PM

live again...

Posted by: Gerald Oct 3 2018, 02:01 PM

They had to make an important decision. Therefore the delay.

Spectrometer needs to be in contact with the surface.

Radiometer will tell about thermal conductivity.
Important for deflection of asteroids: What's the arrangement of grains?

Magnetometer: Extremely sensitive, seeing separation, and operation of instruments. Magnetic field data to be cleaned from those instrument operation fields.
They're going to be tired and will drink a beer this evening. Tomorrow, and until Friday, they'll take a look at the data. A first draft of evaluation will take a few more days of computation. But complete evaluaton will take years.

Posted by: Weywot Oct 3 2018, 02:19 PM

Also interesting: Magentometer team decided to switch off the instrument to safe power, as the have enough data. Let's hope the second sol goes well. The estimate of 16 h battery time probably does not allow for surviving a third night.

Posted by: mcmcmc Oct 3 2018, 03:04 PM


I read that expected battery life is https://twitter.com/haya2e_jaxa/status/1047311778886176768and it's not rechargeable (no solar panels), and delivery occurred https://twitter.com/haya2e_jaxa/status/1047325760011288577
So MASCOT mission should come to its end at around 18:17 GMT, 3 hours from now.

Posted by: Weywot Oct 3 2018, 03:10 PM

Indeed. There will be another press conference in 25 min, maybe they tell us more about the expected life time of the battery. I think it is targeted to last at least two sols in the worst case. Also in the grphic from JAXA, end of mission (EOM) is during the third night. Let's hope for the best, and that the DLR team as uploaded a energy saving program for the third night, so MASCOT may have the chance to upload the data in the next morning, if it survives.
Otherwise the last hours in the night without contact are wasted.

The technical reason is the mass constraint. With just 10 kg, solar panels and rechargables are just too heavy. Rechargables and do not have the energy density compared to non-rechargable batteries. Also, the location MASCOT finally settles was unknown, so no sun light guaranteed. And as we have seen with Philae, if the additional power from solar is required for the science goal, this just adds to the risk.

Posted by: neo56 Oct 3 2018, 07:18 PM

I added a scale to the first picture we have from MASCOT, and Buzz Aldrin to better figure out the scale (like Mystery Man of fredk wink.gif )
The altitude at which this picture was taken in 25 m and not 40 m as it was previously stated.


Posted by: Weywot Oct 3 2018, 08:49 PM

Very nice, those are some big bolders. And again, shadows in the "right" direction makes it so much easier to grasp for my brain.

https://www.youtube.com/watch?v=wSoEapbchGA

JAXA press conference for MASCOT with english translation.

Posted by: nprev Oct 3 2018, 10:52 PM

QUOTE (neo56 @ Oct 3 2018, 11:18 AM) *
I added a scale to the first picture we have from MASCOT, and Buzz Aldrin to better figure out the scale (like Mystery Man of fredk wink.gif )


The official unit of all future photographic scale references on Ryugu is now the "Aldrin". laugh.gif

Posted by: AndyG Oct 4 2018, 12:28 AM

QUOTE (nprev @ Oct 3 2018, 11:52 PM) *
The official unit of all future photographic scale references on Ryugu is now the "Aldrin". laugh.gif


Remarkable to consider that some of those human-sized boulders 'weigh' less than a kilo. Aldrin could be chucking them all over the place. (...slowly).

Andy

Posted by: Reed Oct 4 2018, 07:00 AM

JAXA announced that live navcam image updates are over for this operation: https://twitter.com/haya2e_jaxa/status/1047724464056782853

QUOTE
[MASCOT] October 4 at 13:20 JST: The spacecraft is still hovering at an altitude of about 3km, but the real-time broadcast of the navigation images captured by the ONC-W1 has ended. Thank you for watching! http://www.hayabusa2.jaxa.jp/en/galleries/onc/nav20181002/ … #AsteroidLanding

Here's all the images assembled into an animation
https://flic.kr/p/PyxrCm

The 3km hover phase at the end gives a nice feel for the rotation

Posted by: mcmcmc Oct 4 2018, 11:38 AM

Mission finished. If accomplished... who knows?
https://twitter.com/MASCOT2018/status/1047806424334655488

Posted by: Blue Sky Oct 4 2018, 12:58 PM

QUOTE (mcmcmc @ Oct 4 2018, 07:38 AM) *
Mission finished. If accomplished... who knows?
https://twitter.com/MASCOT2018/status/1047806424334655488

The DLR boffins seem much slower in releasing images than their JAXA counterparts and less concerned with public relations generally. (The goofy first-person tweets do not count.) All that data has to have been transmitted from the surface already, since the batteries have died so perhaps waiting on board Hayabusa.

Posted by: Paolo Oct 4 2018, 01:16 PM

QUOTE (Blue Sky @ Oct 4 2018, 02:58 PM) *
The DLR boffins seem much slower in releasing images than their JAXA counterparts and less concerned with public relations generally.


remember Philae, Rosetta's OSIRIS etc. and don't hold your breath for new images.
We have to hope for some embedded scientist to release all the images as someone did for Huygens.

Posted by: Weywot Oct 4 2018, 07:08 PM

In the press conferences yesterday, it was said, that all data will be downloaded from Hayabusa2 on Friday. Considering, that we got updates nearly every 2 h yesterday from the leading members of the MASCOT team, who were surely occupied otherwise, I think the DLR already did a great job covering the event. Ok, compared to thier performance in this regard on other projects.
Also, JAXA has some nice live coverages, but only with the wide field camera. From all the other instruments, and the MINERVAs, too, the data release is not immediate. We have to remember, which agency does the mission and under what premise. I am not sure about JAXA, but thier main "audience" is Japanese. For Rosetta, ESA was bound by contracts to the very slow release of data that we see now. Maybe not suited for todays culutre, but it was fine at the time the mission was planned. Yes, NASA is very open, but that's how it sees its role in the USA. Concerning the DLR, the culture in Germany is not so much the US view of "tax-payers money, so show the results to the tax-payer", but more state funded research. So the obligation to publicly present the work is far less.

This being said: Where are the images from MASCOT from the surface?? wink.gif

Posted by: djellison Oct 4 2018, 08:18 PM

As a comparison - the camera on MASCOT ( MasCam ) is somewhat related to the CIVA cameras on Philae.

4 CIVA images were released to the public after Philae's landing

The full CIVA data was finally released to the ESA PSA in August of this year. That's 13.5 years after the first data was collected by CIVA and 3 years after the end of Philae's mission

Patience is going to be required. Lots of it.

We have been thoroughly spoiled by MER, MSL, Cassini and New Horizons. It is quite apparent that other agencies do not consider that kind of image release policy to be the new normal.

Posted by: Baywa Oct 4 2018, 09:39 PM

"Inside Information" from a participant of the IAC: There is going to be a press conference at the IAC tomorrow (Friday) at 6:30 UTC, so in about nine hours. But I haven't seen any announcements, tweets so far.

Posted by: bobik Oct 5 2018, 05:20 AM

It would be better if everyone would follow rule 2.6. Your comments will be deleted. rolleyes.gif Or does rule 2.6 apply only to NASA missions? huh.gif

Edit: I see, Lex Sternia! laugh.gif

Posted by: Weywot Oct 5 2018, 06:01 AM

Don't think so, thanks for the reminder.

IAC live stream can be followed here: http://www.iafastro.org/iac-2018-live-streaming/ Unfortunately, it costs 20 €.

@Baywa: Are on the show and can tell us what will be presented?

Posted by: Baywa Oct 5 2018, 07:03 AM

@Baywa: Are on the show and can tell us what will be presented?
[/quote]

No, I'm not. But Elizabeth Tasker @girlandkat is tweeting. Have to hurry, breakfast!

Posted by: akuo Oct 5 2018, 07:53 AM

DLR's site now has some images, click the side arrows to see all three images:
https://www.dlr.de/dlr/desktopdefault.aspx/tabid-10081/151_read-30138/#/gallery/32253

Posted by: MarcF Oct 5 2018, 07:58 AM

Some previews on twitter by @davide_coco91 https://twitter.com/davide_coco91

Video of MASCOT leaving Hayabusa and picture of surface at hopping location number 2.

Posted by: wildespace Oct 5 2018, 08:03 AM

Keep an eye on Twitter, hashtag #IAC2018

Here's a surface photo from MASCOT!



Cropped and colour-corrected from this tweet: http://twitter.com/davide_coco91/status/1048103752262193152

Posted by: Marcin600 Oct 5 2018, 08:17 AM

a new picture from MASCOT - just above the surface of Ryugu

 

Posted by: Marcin600 Oct 5 2018, 09:08 AM

QUOTE (akuo @ Oct 5 2018, 09:53 AM) *
DLR's site now has some images, click the side arrows to see all three images:
https://www.dlr.de/dlr/desktopdefault.aspx/tabid-10081/151_read-30138/#/gallery/32253




 

Posted by: Marcin600 Oct 5 2018, 09:13 AM

These two pictures are from 10 - 20 (25) m above the surface, before the first landing of MASCOT

Posted by: yoichi Oct 5 2018, 09:37 AM

http://www.hayabusa2.jaxa.jp/topics/20181005_MSC_ONC/


Posted by: yoichi Oct 5 2018, 01:08 PM

http://www.hayabusa2.jaxa.jp/en/topics/20181005e_MSC_ONC/

The small asteroid lander, MASCOT, that was developed in Germany and France, was successfully separated from the Hayabusa2 spacecraft on October 3 and delivered safely to the surface of Ryugu. After landing, MASCOT acquired scientific data on the asteroid surface, which was transmitted to the MASCOT team via the spacecraft. Scientific analysis of this data is expected to be performed by the MASCOT team from now onwards.

From the Hayabusa2 spacecraft, we attempted to capture the separated MASCOT using the three optical navigation cameras (ONC-T, ONC-W1, ONC-W2). When the image data was received from the spacecraft, we could confirm that MASCOT appears in images photographed with the ONC-W1 and ONC-W2.

Posted by: Explorer1 Oct 5 2018, 01:13 PM

That first image is almost unreal, Yoichi, thanks for finding it for us non-Japanese speakers! Wow!

Posted by: djellison Oct 5 2018, 04:28 PM

Was able to extract some 3D data from the three images from Hayabusa during MASCOT's decent

https://sketchfab.com/models/c7155bfcac774d65bb4688709b9faca3

Posted by: elakdawalla Oct 5 2018, 04:30 PM

Anybody know the proper credit on MASCOT images?

Posted by: Explorer1 Oct 5 2018, 04:40 PM

QUOTE (elakdawalla @ Oct 5 2018, 11:30 AM) *
Anybody know the proper credit on MASCOT images?


According to here (scroll to MASCOT instruments): https://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10977/1757_read-24573/#/gallery/31165

"Institute of Planetary Research, DLR"


Posted by: elakdawalla Oct 5 2018, 04:48 PM

Thanks for the link, that's useful. I'm gonna go ahead and add JAXA and CNES in as well...

Posted by: Blue Sky Oct 5 2018, 04:58 PM

Still no information on scale, so it is hard to know what we are looking at. What I am interested in is the first picture, showing the DLR control room. A woman is in the left foreground looking at the projected information on the wall. In the left part of that information is an image of some rocky terrain that does not seem to be among the other pictures they have released.

Posted by: Baywa Oct 5 2018, 05:48 PM

QUOTE (elakdawalla @ Oct 5 2018, 06:30 PM) *
Anybody know the proper credit on MASCOT images?


On the latest images from MASCOT it says Credit: MASCOT/DLR/JAXA

see https://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10081/151_read-30138/#/gallery/32249

Click on "Information"

Posted by: wildespace Oct 5 2018, 08:34 PM

An attempted red-green stereo image using the frames from MASCOT descent:



Creadit: JAXA/University of Tokyo/Kochi University/Rikkyo University/Nagoya University/Chiba Institute of Technology/Meiji University/University of Aizu/AIST/Kakitsev ninja.gif

Posted by: neo56 Oct 5 2018, 08:36 PM

Hayabusa2 and MASCOT pictures of the same scene from a different point of view:


Posted by: Hungry4info Oct 5 2018, 11:30 PM

There's a much higher quality image of the "hopping location #2" pic from MASCOT on the https://www.dlr.de/dlr/desktopdefault.aspx/tabid-10081/151_read-30138/#/gallery/32253 website. It's embedded into a margin smaller than the image, which shrinks it a bit, but if you open the https://www.dlr.de/dlr/Portaldata/1/Resources/portal_bilder/2018/2018_4/05Bild_16zu9_MASCOT_LastOrder_xl.jpg itself, you can see a lot more detail.


 

Posted by: Roby72 Oct 5 2018, 11:40 PM

I see on the MASCOT pictures that one side is not focused..somewhat blurry ...is there any reason for this ?

My guess is, that it is not dejustet but if you land upright you have the nearer objects better in focus than the more far away and you not need a focusable lens assembly which adds some risk to the lander.
Or is it really out of focus ?

Rob

Posted by: Steve G Oct 6 2018, 01:15 AM

I was wondering about the same thing. Either the image sensor isn't aligned to the lens due to temperature shift or related stress, or, it's deliberately like that so when the spacecraft is on the surface, and righted, both the foreground and background will be in focus like a tilt shift camera where you change the angle of the negative to increase depth of field.

Posted by: neo56 Oct 6 2018, 07:49 AM

I aligned each 3 frames of the MASCOT animation in relation to Ryugu surface:


Posted by: Explorer1 Oct 6 2018, 03:27 PM

No new pictures, but some science results in this article: https://spaceflightnow.com/2018/10/05/mascot-lander-hops-around-asteroid-exceeding-scientists-expectations/

QUOTE
What we’ve learned so far from the pictures is it looks like the surface is more consolidated rocks overlaid by a thin layer of particulate material,” Grott said.

Posted by: Stefan Oct 11 2018, 07:01 PM

QUOTE (Steve G @ Oct 6 2018, 02:15 AM) *
I was wondering about the same thing. Either the image sensor isn't aligned to the lens due to temperature shift or related stress, or, it's deliberately like that so when the spacecraft is on the surface, and righted, both the foreground and background will be in focus like a tilt shift camera where you change the angle of the negative to increase depth of field.

It is deliberately like that. It's called the Scheimpflug principle.

There's a press conference tomorrow with some new material.

Posted by: yoichi Oct 12 2018, 12:15 PM

https://www.dlr.de/dlr/presse/en/desktopdefault.aspx/tabid-10172/213_read-30235/year-all/#/gallery/32338
Numerous boulders, many rocks, no dust: MASCOT's zigzag course across the asteroid Ryugu

Posted by: Explorer1 Oct 13 2018, 03:35 PM

Finally surface images! Nice oblique view of the giant south pole boulder too! The top seems to be the only big smooth part of Ryugu....

And we have a name for the landing site: 'Alice's Wonderland'

Posted by: stevesliva Oct 15 2018, 02:59 PM

QUOTE (yoichi @ Oct 12 2018, 08:15 AM) *
https://www.dlr.de/dlr/presse/en/desktopdefault.aspx/tabid-10172/213_read-30235/year-all/#/gallery/32338
Numerous boulders, many rocks, no dust: MASCOT's zigzag course across the asteroid Ryugu


For those like me wondering about the "no dust" in the title, it's described only as "fine material" in the accompanying text.

No dust? Makes you wonder if the dust gets cemented.

Posted by: Phil Stooke Oct 15 2018, 07:21 PM

It's easy to make dust through micrometeorite impacts, and some at least should be retained. But cementing or consolidating it is much more difficult. More likely it's a sifting effect, where jostling by impacts causes large chunks to rise and small objects to fall into spaces between them. On Itokawa the same thing was seen except that in some low-lying areas the fine materal became concentrated in smooth patches. We don't see that here, maybe because Ryugu is more equidimensional.

Posted by: Hungry4info Jan 30 2019, 11:10 PM

This abstract at the 50th LPSC has a new image from MASCOT, taken during local night with the red LED on. The red ellipse is labelled as the radiometer field of view. Is it possible to remove it from the image to try to restore the background image?
https://www.hou.usra.edu/meetings/lpsc2019/pdf/1267.pdf


 

Posted by: elakdawalla Jan 31 2019, 01:13 AM

Needs a little cosmetic work around the edges of the ellipse, but here's a quick and dirty version:

 

Posted by: MahFL Jan 31 2019, 03:54 AM

QUOTE (elakdawalla @ Jan 31 2019, 02:13 AM) *
Needs a little cosmetic work around the edges of the ellipse, but here's a quick and dirty version:


Anyone know what the scale is we are looking at ?

Posted by: Baywa Jan 31 2019, 03:17 PM

QUOTE (MahFL @ Jan 31 2019, 04:54 AM) *
Anyone know what the scale is we are looking at ?
In the article it says " MARA observed a rock formation of approximately 60 cm diameter, which is shown in Fig. 1." Fig.1. being the attached picture. But I'm not quite sure: 60cm may also refer to the red ellipse.

Posted by: Gladstoner Jan 31 2019, 11:54 PM

QUOTE (elakdawalla @ Jan 30 2019, 07:13 PM) *
Needs a little cosmetic work around the edges of the ellipse, but here's a quick and dirty version:


Cleaned up, with a bit of necessary artistic license:



Posted by: centsworth_II Feb 1 2019, 07:21 AM

QUOTE (MahFL @ Jan 30 2019, 11:54 PM) *
Anyone know what the scale is we are looking at ?


If my math is right and the pixels on the image are accurate to the original, I get the 10 cm bar (in black) based on 500 pixels at 0.2mm per pixel at the bottom of the image as mentioned in the image caption.

I get the 60cm bar (in yellow) based on 300 pixels at 2mm per pixel (rough estimation, based on 0.2mm per pixel at the bottom of the image and 3mm per pixel near the horizon as mentioned in the image caption).

Disclaimer: I am not an accomplished image interpreter.

Posted by: Hungry4info Jul 15 2019, 09:27 PM

"MASCOT confirms what scientists have long suspected
Small fragments of carbon-rich asteroids are too fragile to survive entry into Earth’s atmosphere"

Press release:
https://www.dlr.de/dlr/presse/en/desktopdefault.aspx/tabid-10172/213_read-36790/?fbclid=IwAR0sZ__tvS1OfXxk7-ZWodVoeBCPgxJPfrfjPQkwLyKdx9fOby8qyxi5AWo

Original paper:
Low thermal conductivity boulder with high porosity identified on C-type asteroid (162173) Ryugu
https://www.nature.com/articles/s41550-019-0832-x?fbclid=IwAR0kNmu1FzdbH_fBYOFLcWTGNcX9QrPCUbVRjSUofU1SrPquGwVWtmiCPak

Posted by: Hungry4info Aug 25 2019, 03:28 AM

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-photos-de-ryugu-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 https://science.sciencemag.org/content/365/6455/817 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)


 

Posted by: Hungry4info Aug 25 2019, 04:10 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.

 

Posted by: Marcin600 Aug 26 2019, 11:24 PM

Beautiful photos!
https://www.dlr.de/dlr/presse/en/desktopdefault.aspx/tabid-10172/213_read-37306/year-all/#/gallery/36381 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



 

Posted by: Marcin600 Aug 26 2019, 11:30 PM

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...”)

Posted by: Marcin600 Aug 26 2019, 11:54 PM

In the https://www.dlr.de/dlr/presse/en/desktopdefault.aspx/tabid-10172/213_read-37306/year-all/#/gallery/36381 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...”

Posted by: Marcin600 Aug 27 2019, 12:08 AM

And another quote from https://www.dlr.de/dlr/presse/en/desktopdefault.aspx/tabid-10172/213_read-37306/year-all/#/gallery/36381 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..."

Posted by: Marcin600 Aug 27 2019, 12:46 AM

I added the scale bar according to the original description under the color picture


 

Posted by: Marcin600 Aug 27 2019, 01:05 AM

A little play with a changing perspective in this crazy but beautiful world


 

Posted by: Marcin600 Aug 27 2019, 01:23 AM

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?

Posted by: Marcin600 Aug 27 2019, 01:33 AM

I just found the https://mascot.cnes.fr/sites/default/files/drupal/201908/image/bpc_mascot_photo1.png

Now the scale is OK rolleyes.gif

Sorry about that!

 

Posted by: Marcin600 Aug 27 2019, 01:53 AM

And yet only a larger version (b/w) of the night picture of the surface of Ryugu (from https://phys.org/news/2019-08-images-asteroid-probe-clues-planet.html?utm_source=TrendMD&utm_medium=cpc&utm_campaign=Phys.org_TrendMD_1 )


 

Posted by: Marcin600 Nov 16 2019, 08:20 PM

I am not sure if the color night picture of the Ryugu's surface appeared here in such resolution ( from https://www.dlr.de/content/en/articles/news/2019/03/20190822_the-near-earth-asteroid-ryugu-a-fragile-cosmic-rubble-pile.html ):
(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

 

Posted by: Paolo Dec 6 2019, 10:30 AM

the latest issue of Astronomy & Astrophysics has three papers (in free access!) on MASCOT:

https://www.aanda.org/articles/aa/full_html/2019/12/aa36757-19/aa36757-19.html

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).


https://www.aanda.org/articles/aa/full_html/2019/12/aa36759-19/aa36759-19.html
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.


https://www.aanda.org/articles/aa/full_html/2019/12/aa36760-19/aa36760-19.html
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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