"...The spacecraft descent has been autonomously aborted at an altitude of about 50m. Hayabusa2 is currently rising to the home position. Telemetry from the spacecraft has been confirmed and the spacecraft is normal, but the target marker has not been dropped...": https://twitter.com/haya2e_jaxa

That's unfortunate. Wonder if the rough terrain made it difficult for the lidar to provide consistent data.

What follows is from a today's local newspaper.

H2 was meant to descend to 10 m height on 16th to identify suitble landing sites.

However, in reality descenht was autonomously aborted at 50 m height and the target marker was not dropped.

Close examination showed that H2 thought that it was at 9km height when the sensitivity of the height detector
was changed at that time. H2 thought that something was wrong and started rising.

On the other hand photos were taken at around 500 m of landing site candidates and they are clear photos.

The poject manager thinks that JAXA will go for a landing site candidate very close to craters and drop a target marker.
He thinks that there is no delay due to this time's autonomous rising.

P

Many thanks

Yesterday (19/5/22) took place JAXA press conference regarding last Hayabusa2 action on May 16 and pdf material from this session was published (in Japanese).

Two pictures of the new crater from 500 and 600 m:

My/Google Translate very rough translation of several conclusions from Japanese pdf :

page 7:

The reason for the normal abort is that there was a problem with LIDAR distance measurement



page 9:

About normal abort

Event
• The spacecraft detected an altitude anomaly in LIDAR, and then moved to the normal abort state by autonomous judgment (The descent ceased and turned upward).

- "Normal abort" is a mode triggered in the case of a minor abnormality (eg, some sensor output abnormalities, etc.).

■ The cause of high value abnormality
• The reception sensitivity of LIDAR laser light can be adjusted according to the altitude. This time, the reception sensitivity was switched by an automatic sequence when passing 50 m. Noise data at that timing, because of contamination, LIDAR output an abnormal altitude value.

– This is the first time that the receiver sensitivity switching has been performed at low altitude. The descent accuracy of "Hayabusa 2" is higher than originally expected. As a result, even when LIDAR laser light hits the target marker, LIDAR was a measure to prevent it.

– How noise data is mixed up depends on the environment of Ryugu and the situation of “Hayabusa 2”. It was a case and difficult to predict in advance.

■ Future measures
• After this event, we found a switching method that could reliably prevent noise mixing. From the next time on, adopt the formula.



page 13:

3. Future operation policy

■ Concept of operation plan from May to July

• Currently, Ryugu is approaching the sun (perihelion is September). Since the surface temperature of the asteroid will rise in the future, landing is possible until the beginning of July.

• After examining the topography of the crater and the condition of the spacecraft by mid-June, actually from late June to July, we decide whether to implement touchdown operation in season.

• Target point: The area where there is an ejector (scattered material) from an artificial crater

• Operation name: "Pinpoint Touchdown" (PPTD)

• Two or three low altitude descent observation operations will be implemented between May and June before PPTD operation. Landing by it, as well as detailed topographical observation of the candidate site, target markers will be used as a landing gear according to the situation.

Dropping:
• First time: 5/14 to 5/16
Operation name: PPTD-TM1-The target marker can not be dropped
• Second time: 5/28 to 5/30
Operation name: PPTD-TM1A
• Third: 6/10 weeks
Operation name: PPTD-TM1B (provisional)
• Drop a target marker on one of the landing candidate points in PPTD-TM1A operation. The release point is this time. C01 was selected as the best area from among the obtained detailed images.

Pandaneko, could you verify this translation from Japanese? (until the official pdf in English appears)

I am amazed at Google translation accuracy. I confirm that what Google says is more or less true.
If I am to add something it is page 9, as follows.

About normal abort

Event

• The spacecraft detected an altitude anomaly in LIDAR, and then moved to the normal abort state by autonomous
judgment (The descent ceased and turned upward).

- "Normal abort" is a mode triggered in the case of a minor abnormality (eg, some sensor output abnormalities, etc.).

■ The cause of high value abnormality

• The reception sensitivity of LIDAR laser light can be adjusted according to the altitude. This time, the reception sensitivity
was switched by an automatic sequence when passing 50 m. Noise data at that timing crept in, because of contamination,
LIDAR output showed an abnormally high altitude value.

– This is the first time that the receiver sensitivity switching has been performed at such a low altitude. Because descent accuracy
of "Hayabusa 2" was found to be higher than we originally had expected, we wanted to make sure that even when LIDAR
laser light hits the target marker (which has a very high reflectivity), LIDAR does not get it wrong. That was the pirpose of
sensitivity changing.

– How noise data is mixed up depends on the environment of Ryugu and the situation of “Hayabusa 2”. Noise contamination
at that stage was difficult to predict in advance. However,

■ Future measures

• After this accident, we found a switching method that could reliably prevent this kind of noise mixing. From next time on,
H2 will be using the improved formula.

P

Stereo views of the new crater from the 500/600m images. Cross-eyed:
Click to view attachment
Anaglyph:
Click to view attachment

Wow, that is excellent stereo!

Wholeheartedly agree. I often have trouble making these stereo posts "read." Not so with this one!

Official English version of pdf from last press conference has already been published.

And slightly larger versions of new crater pictures from 500 and 600 m are on the Hayabusa2 site.

The PPTD-TM1A operation it's just starting. This time the marker is to be dropped very close to the new crater or even inside it! The lowest planned height - 10 m - at 11:23 JST = 2:23 UTC, May 30. If everything goes well we will see even better photos of new crater

The descent for the PPTD-TM1A operation has begun. A new image is posted about every half-hour here.

Thanks for the comments! Here are the same stereo views using the high resolution images. Cross-eyed:
Click to view attachment
Anaglyph:
Click to view attachment

Target marker has been droped from 10 m successfully (link to animated gif)

My analysis of target marker's location:

And shadow of the marker (?):

final position of the marker

Image of the target maker right after deployment.

Second sample collection is decided and scheduled for july 11th !

https://www3.nhk.or.jp/nhkworld/en/news/20190625_34/

Here is an updated map of Ryugu showing the impact and target marker locations.

Phil

Click to view attachment

The descent for the 2nd sampling attempt is in progress. Navigation images in real time here.

The JAXA twitter page is saying the second sampling was a success.

Click to view attachment

That, and more, here
http://www.hayabusa2.jaxa.jp/en/topics/201..._ImageBulletin/

Images and movie of the 2nd touchdown:
http://www.hayabusa2.jaxa.jp/en/topics/20190726e_TD2_images/

That wide angle image halfway down the page shows the impact crater from the explosive charge, according to this labelled image on Twitter: https://twitter.com/haya2e_jaxa/status/1154655427491008513

Report in english from July 25th press briefing,
press briefing 2019/07/25
lots of details concerning the second touchdown
departure from the asteroid is slowly approaching,
no comment about the deployment of the Minerva-II2 lander

Even if they weren't able to restore functionality, it doesn't seem useful to hold onto the extra mass for the trip back...

Time to update the map with the new sample collection site.

If the last lander is dropped there will be one more update. If not this will probably be the last, unless I improve the base image. I think I saw somewhere that the lander drop would be in September (possibly from the NASA Exploration Science Forum videos).

Phil

Click to view attachment

2019-08-22 Hayabusa2 reporter briefing in English :

- Place names related to the artificial crater
- Status of MINERVA-II1
- Future plans
- Capsule re-entry sequence and recovery method

About MINERVA-II2:
„In order to obtain meaningful results using Rover-2 (university consortium development), separation from a relatively high altitude (about 1km) is planned, with the descent to the asteroid surface over time used to estimate the asteroid’s gravitational field by monitoring the descending orbit”.

• September 5 - „the target marker separation operation will be performed as a rehearsal for MINERVA-II2 separation. The two target markers will be separated at an altitude of about 1km”
• September 24 (planned) - details of this operation will be explained at the press briefing
• Nov-Dec 2019 - departure from Ryugu;
• end of 2020 - capsule re-entry


Omusubi-Kororin crater: "...The crater will also continue to be referred to as the “SCI crater”, depending on the situation..."


(Image credit: JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, University of Aizu, AIST. I added new boulder names and scale bar)

And from previous press material (July 25) - photo of SCI crater (Omusubi-Kororin) from above the Ryugu surface
(Oryginal picture from the Hayabusa2 website. Credit:JAXA, modificated)

My attempt to link both views of the SCI crater (oryginal pictures from the Hayabusa2 website: 1 and 2 . Credit:JAXA, modificated ):

New names of boulders inside SCI crater (Oryginal picture on the Hayabusa2 website. Credit:JAXA, modificated)

September 3: "...On August 29, the back-up reaction wheel that has not been used since October last year was tested, and an abnormal value (an increased torque) was detected. The spacecraft therefore autonomously moved into the Safe-Hold state. ... On August 30...the spacecraft returned to normal [state]. However, as the spacecraft moved away from the home position due to entering Safe-Hold, we are currently having to return to the home position..."

September 6 [Google translation]: "Hayabusa 2" was away from the home position (HP), but now it has returned to almost HP. It was planned to arrive at HP this weekend, but given the possibility of approaching Typhoon No. 15 and affecting the operation of ground stations on Sunday and Monday, HP will arrive on Tuesday (9/10). [We] adjusted the speed of the spacecraft."

September 3 (again): "...The ’Target marker separation operation’ scheduled for September 5 has been postponed due to the spacecraft entering the Safe-Hold state...We will report again about the target marker separation when a new schedule has been decided."

„Image of the first target marker (TM-E) separation”.
„This is an overlay of images taken every 4s (for ~1min) as the spacecraft ascends at 11cm/s. TM descent speed is still almost zero. Separation time: 2019/9/17 at 01:17 JST. Altitude: 1km.”

„The separation image of the 2nd target marker, TM-C.”
„This is an overlay of images taken every 4s (for ~1min) while the spacecraft ascends at 11cm/s. TM descent speed is still almost zero. Separation time: 2019/9/17 at 01:24 JST. Altitude: 1km.”

From Jaxa twitter :

[MINERVA-II2] Today (09/28) at 10:30 JST (on-board time), the spacecraft began its descent from the home position for the separation operation of MINERVA-II2 (Rover2).

Was there ever any follow-up on whether they restored functionality, or what the original problem was? Is it just a brick being dropped off before departure, or can we expect data (and images)?

It's not functioning. I think it is being dropped to monitor its motion as a probe of gravity.

Phil

A press conference on Minerva-II2 was held on September 24 - pdf materials (in Japanese only) are: here and here

Terribly coarse Google translation - I am very sorry for that - but reflecting the sense of the current situation of the lander:


MINERVA-II2: separation from 1 km - October 3, 0:00~2:00 JST; impact - October 8 (JST)

MINERVA-II2 - Current status and purpose of separation operation:

- In the operation check on the machine, although communication can be established between Hayabusa 2 and MINERVA-II2, the MINERVA-II2 data processing system cannot be started normally. This situation is still the same
- In order to achieve scientific results in the MINERVA-II2 separation operation, the Hayabusa 2 team, the US University of Colorado, Kyushu Institute of Technology, and Tohoku University were examined.
- The aim is to separate the MINERVA-II2 at a slightly higher altitude and make the Ryugu go around several times instead of moving the surface and imaging after the landing. If we can observe the orbital motion from Hayabusa 2, we can expect to know more about Ryugu's gravitational field.

Significance of MINERVA-II2 separation / round operation:
- Acquire scientific data that contributes to improving the accuracy of Ryugu's gravity model
- Accumulate orbiting technology by orbiting small artifacts on asteroids

Separation / round operation plan:
- Separated for the surface of Ryugu at an altitude of about 1km
- Separation from the equator toward Ryugu rotation direction
- Attempt optical imaging of the motion after separation using ONC-W1 & W2 and ONC-T

Predicted value for throwing trajectory:
- Orbit type-Equatorial orbit
- Orbit life (predicted)-about 5 days (± several days)
- Number of laps (forecast)-about 8 times (± several times)
- Period (first period) (prediction)-about 17 hours (± several hours)

MINERVA-II2 Ryugu grounding and subsequent operation:
- The ground contact speed of Rover 2 is about 0.5 m / s. This is the same level as dropping from a height of about 1.5 cm on the ground. The rover is caused by a grounding impact.
- Less likely to break
- It is the original experimental item of MINERVA-II2-Micro-hop movement by eccentric motor (Tohoku Univ.) - Elastic reaction reaction movement using leaf spring (Osaka Univ.)-Play force reaction movement using permanent magnet (Tokyo Denki University)
- MICAM camera (Tokyo University of Science) cannot be implemented unless the data processing system is restored.
- As for the recoil movement mechanism using bimetal (Yamagata University), the rover may move due to temperature changes due to sunshine and shade on Ryugu. However, it is difficult to check the status of movement

In short, as Phil wrote: they will drop it from a 1 km and watch how it orbits the asteroid and lands after a few days - studying the gravitational field.

If nothing changes (they won't be able to restart Minerva's systems) - no photos from the lander should be expected. Only photos of Minerva in space and possibly on the surface of Ryugu. Maybe also a little hops on the surface (jumping brick)

From JAXA Twitter:
"MINERVA-II2 is confirmed to have separated today (10/3) at 01:38 JST. The separation time was 00:57 JST (on-board time). The spacecraft condition is normal."
"This is MINERVA-II2 captured by the wide-angle optical navigation camera (ONC-W2) immediately after separation. Radio-waves are also being received from MINERVA-II2. (Credit: JAXA, Chiba Institute of Technology & collaborators)"
"...the operation is ongoing! In the future, we will observe the orbital motion of MINERVA-II2 after its separation."

On November 5-7, 2019 took place a meeting - workshop "Asteroid Science in the Age of Hayabusa2 and OSIRIS-REx". The workshop website has a collection of interesting abstracts (pdf’s) about scientific results from Ryugu and Bennu, containing article about the artificial SCI crater on Ryugu


Some new data from this article [text highlights are mine, the picture - Figure 1 - comes from the cited article]:

SPACE IMPACT EXPERIMENT ON RYUGU: ARTIFICIAL CRATER. T. Kadono et al. Asteroid Science 2019 (LPI Contrib. No. 2189)

„...This image was taken by ONC-T in the low-altitude operation at 1.7 km altitude... A crater rim also appeared as a part of a semicircle in the image. The estimated location of the crater rim is shown as a dashed curve. The deposition rim is a strong evidence for the crater formation occurring in the gravity-dominated regime.

The diameter from a point on the rim to an opposite Drim was ~15 m. Using an empirical equation D = Drim/1.3, where D is the crater diameter at an initial surface elevation [9], we determine the crater radius of the SCI crater R = D/2 to be 6.5 m.

We calculate the SCI crater radius using the conventional π scaling law applied for a typical sand surface [9]. We find that the SCI impact crater is about 5% smaller than that calculated for sand. In spite of the difference, it should be formed on a cohesionless surface such as one made of sand, because even a small amount of cohesion limits the crater growth in this microgravity environment and prohibits the crater diameter to be larger than 10 m. Thus, we can reasonably conclude that the surface of Ryugu is composed of sand-like cohesionless materials.

We found a pit close to the impact point on the crater floor (an arrow in Fig. 1). The pit entrance is at a depth of 1.7 m from the initial surface; the diameter and the depth of the pit is >2 m and 0.6 m, respectively. The pit has a conical shape similar to a simple crater in laboratory experiments [8]. The pit might result from the SCI impact on a subsurface layer with a cohesion strength. The cohesion strength of the subsurface layer is estimated by the dynamic pressure generated on the layer, which is caused by the material flow with the particle velocity. We calculated this pressure from the Maxwell’s Z-model [9]. Assuming the typical z value of 3 for granular materials, R = 6.5 m, a non-cohesive upper layer with a thickness of 1.7 m, and a pit diameter of 2 m formed on a cohesive subsurface layer, the dynamic pressure can be obtained as about 300 Pa at the center of the pit and about 130 Pa at the rim of the pit. Thus, the cohesion strength of the subsurface layer is speculated to be smaller than about 300 Pa and larger than about 130 Pa...”

[8] Melosh H. J. (1989) Impact cratering: A geologic process.
[9] Housen K. R. and Holsapple K. A. (2011) Icarus, 211, 856-875.

And another interesting article from the same workshop: "THE ROLE OF ELECTROSTATIC DUST LOFTING IN SHAPING THE SURFACE PROPERTIES OF ASTEROIDS"

and this : "PLANS OF HAYABUSA2’s ONC IMAGE ARCHIVING AND PUBLIC RELEASE"

and a nice picture from this article : "Nature of Roughness of Ryugu Revealed by Thermal Simulation of High Resolution Digital Elevation Model". S. Tanaka et al. Asteroid Science 2019 (LPI Contrib. No. 2189):

Hayabusa2 began returning to Earth on November 13, at 10.05 JST

From JAXA twitter: "...In the end I decided to leave Ryugu. Departure tomorrow (November 13) at 10:05 (JST). The RCS thruster (chemical engine) is to start moving away from Ryugu at a speed of 10 cm / s....After leaving the gravity zone of Ryugu, we will continue preparations for the return to Earth by conducting a trial start of the ion engine..."

Press material - pdf, only in Japanese

Press conference - here

Official JAXA material in English

Real time delivery of navigation Images from the asteroid departure and current informations on JAXA twitter

Interesting conclusions from new article in Icarus magazine - Naoyuki Hirata et al. The spatial distribution of impact craters on Ryugu. Icarus, 5 November 2019, 113527:

"...It seems that the variation in crater density indicates that the equatorial ridge located in the western hemisphere is relatively young, while that located in the eastern hemisphere is a fossil structure formed during the short rotational period in the distant past..."

Image from the cited article:

Final pictures of Ryugu taken by Hayabusa2