P6
Current status:
－2100km as of today, 7 June
－Ion eigines stopped on 3 June for onward journey
－Arrival expected to be 27th June +/- few days
－Optical navigation is underway
P7
・Delta V since 10 January is 393m/s
・Outward operation of the ion engines is now over
・24 kg of zenon consumed, 42kg still remains, total delta V is 1015m/s
P10
・Optical navigation means approaching with camera views
・Reason for above: cordinate uncertainty of about 220km
These are the new (at least to me) inputs in the press conference report about current status
of Hayabusa 2.
P
Full Version: Mission: Hayabusa 2
Ryugu is not symmetrical, is it? Top one third looks darker.
P
P
QUOTE (pandaneko @ Jun 7 2018, 10:07 AM) 
Ryugu is not symmetrical, is it? Top one third looks darker.
Almost impossible to say yet. If Ryugu's centre is a bit below the centre pixel you'd expect the upper pixels to be darker than the bottom ones.
"Ryugu is not symmetrical, is it? Top one third looks darker."
The important thing about this is that you can never trust the appearance of a pixel right on the edge of something. We have no way of telling how much of that pixel is covering Ryugu and how much is covering the black space around it. Usually people assume that you need at least 3 pixels across something to interpret it. In this case that would be 3 pixels across that dark-looking area (about 10 pixels across the asteroid). If it still looks dark then, we know it's dark!
Phil
The important thing about this is that you can never trust the appearance of a pixel right on the edge of something. We have no way of telling how much of that pixel is covering Ryugu and how much is covering the black space around it. Usually people assume that you need at least 3 pixels across something to interpret it. In this case that would be 3 pixels across that dark-looking area (about 10 pixels across the asteroid). If it still looks dark then, we know it's dark!
Phil
Press conference documentation in english:
http://www.hayabusa2.jaxa.jp/topics/press/...ss20180607e.pdf
http://www.hayabusa2.jaxa.jp/topics/press/...ss20180607e.pdf
Q&A continues.
Q. How do you approach Ryugu? My guess is that you first place Hayabusa 2 on the same planar orbit as Ryugu
and then slowly adjust the curvature. Is that right?
Since there is a mass difference speeding up of Hayabusa 2 in trying to catch up with Ryugu may lead to
overshooting. How can you make sure it will not happen?
June 03, 2018 - : 64 year old
A. We conducted an earth swing-by on 3 December 2015 and that was for Hayabusa 2 to move into the same
orbital plane as Ryugu.
After that over 2.5 years we fired ion engines on and off so that Hayabusa 2's orbit becomes closer to that of
Ryugu.
That is to say, we tried to enlarge Hayabusa 2 's orbit little by little. Here, the mass difference is irrelevant to
this operation.
We, however, need to take into account, pull by the Sun, and pull by other planets, in addition to the solar rays
pressure on Hayabusa 2.
In the final stage we need to take into account Ryugu's gravitational pull. That is why we will be conducting
a free fall to 1km height. Hayabusa 2's speed varies depending on where it is flying, maximum speed is
somethinglike 33km/s and slowest is 23km/s.
P
There will be more Q&As.
Q. How do you approach Ryugu? My guess is that you first place Hayabusa 2 on the same planar orbit as Ryugu
and then slowly adjust the curvature. Is that right?
Since there is a mass difference speeding up of Hayabusa 2 in trying to catch up with Ryugu may lead to
overshooting. How can you make sure it will not happen?
June 03, 2018 - : 64 year old
A. We conducted an earth swing-by on 3 December 2015 and that was for Hayabusa 2 to move into the same
orbital plane as Ryugu.
After that over 2.5 years we fired ion engines on and off so that Hayabusa 2's orbit becomes closer to that of
Ryugu.
That is to say, we tried to enlarge Hayabusa 2 's orbit little by little. Here, the mass difference is irrelevant to
this operation.
We, however, need to take into account, pull by the Sun, and pull by other planets, in addition to the solar rays
pressure on Hayabusa 2.
In the final stage we need to take into account Ryugu's gravitational pull. That is why we will be conducting
a free fall to 1km height. Hayabusa 2's speed varies depending on where it is flying, maximum speed is
somethinglike 33km/s and slowest is 23km/s.
P
There will be more Q&As.
Q&A continues.
Q. Sampled materials are likely to be organic in origin. Do you store them in a fridge like place until they
reach Earth? June 03, 2018 - : 58 year old
A. There is no fridge in Hayabusa 2 capsule. It is assumed that the surface temp. on Hayabusa capsule reached
3,000 degrees C.
However, the temp. inside the capsule was kept at less than 100 degrees C. You may think that 100 degrees C
is too high, but the surface temp. on Itokawa was as high as 100, so, there was not much problem.
With Ryugu we think that the surface temp. will be similar, so there is no fridge. We can measure the surface
temp. of Ryugu accurately with the mid infra red camera.
P
Q. Sampled materials are likely to be organic in origin. Do you store them in a fridge like place until they
reach Earth? June 03, 2018 - : 58 year old
A. There is no fridge in Hayabusa 2 capsule. It is assumed that the surface temp. on Hayabusa capsule reached
3,000 degrees C.
However, the temp. inside the capsule was kept at less than 100 degrees C. You may think that 100 degrees C
is too high, but the surface temp. on Itokawa was as high as 100, so, there was not much problem.
With Ryugu we think that the surface temp. will be similar, so there is no fridge. We can measure the surface
temp. of Ryugu accurately with the mid infra red camera.
P
Q&A
Q. There were many troubles with Hayabusa 1's flight. Have you had similar problems this time?
June 03, 2018 - : 19 year old
A. With Hayabusa 1 reaction wheels broke down. They control attitude. There were 3 of them on Hayabusa 1.
One broke before arriving, and another broke immediately after arrival. In addition, one of the four ione engines
on 1 was not in good health, right from the start.
With 2, there has not been any major problem, so far. There are 4 reaction wheels and all of them are healthy.
Also, all 4 of the ion engnines are healthy and mission continues according to original design.
P
There are a little more Qs and As. One thing I came to realise is that rather a lot of xenon
still left is perhaps for moving Hayabusa 2 to its eventual parking position, L2?, L3?, I do not remember,
but I do remember the parking issue JAXA talked about with Hayabusa 1 before they had to burn it
with adiabatic compression.
Q. There were many troubles with Hayabusa 1's flight. Have you had similar problems this time?
June 03, 2018 - : 19 year old
A. With Hayabusa 1 reaction wheels broke down. They control attitude. There were 3 of them on Hayabusa 1.
One broke before arriving, and another broke immediately after arrival. In addition, one of the four ione engines
on 1 was not in good health, right from the start.
With 2, there has not been any major problem, so far. There are 4 reaction wheels and all of them are healthy.
Also, all 4 of the ion engnines are healthy and mission continues according to original design.
P
There are a little more Qs and As. One thing I came to realise is that rather a lot of xenon
still left is perhaps for moving Hayabusa 2 to its eventual parking position, L2?, L3?, I do not remember,
but I do remember the parking issue JAXA talked about with Hayabusa 1 before they had to burn it
with adiabatic compression.
there was a paper at the 2016 IAC Congress (paper no. IAC-16.C1.5.11) on Hayabusa 2 mission extension. four candidates for an NEA flyby have been identified, with the best being 630 m (172034) 2001 WR1, for a flyby on 27 June 2023
Accordning to the log I have been keeping all chemical thrusters, except #2, #4, and #8 have been
fired since 1 June.
P
fired since 1 June.
P
Q&A continues. This is the last in the Q&A box, but JAXA seem to be accepting questions at any time and I may find some more
in due course.
Q. Do you have a plan to make a movie of touch down using an on-borad camera?
June 02, 2018 - : 21 year old
A. This monitor camera was made thanks to the donation from people like you. Therefore, if possible, we would like to make such a movie.
However, there will be all kinds of delicate operational issues during touch down and it is possible that we may not be able to do that,
but we will try our best.
P
in due course.
Q. Do you have a plan to make a movie of touch down using an on-borad camera?
June 02, 2018 - : 21 year old
A. This monitor camera was made thanks to the donation from people like you. Therefore, if possible, we would like to make such a movie.
However, there will be all kinds of delicate operational issues during touch down and it is possible that we may not be able to do that,
but we will try our best.
P
A touchdown movie would be truly spectacular; hope they can manage it! 
From the twitter portion of Hayabusa 2 main web page.
8 June 2018
First TCM01 during optical navigation was conducted. We fired thrusters several times during 12:30 to 13:40 on 8 June, and
accelerated Hayabusa 2 by 24cm/s in minus X, 5cm/s in minus Y, and 14cm/s in plus Z directions. Consequently, the relative distance
is now 1900km, velocity 2.35m/s
6 June
LIDAR was powered on after 2 year long crusing to check its health. We did it step by step, Each command response needs 32
minutes for confirmation. Altogether it took us 5 hours to complete this checking. We cannot use it yet as the distance is still too
large for the LIDAR.
P
8 June 2018
First TCM01 during optical navigation was conducted. We fired thrusters several times during 12:30 to 13:40 on 8 June, and
accelerated Hayabusa 2 by 24cm/s in minus X, 5cm/s in minus Y, and 14cm/s in plus Z directions. Consequently, the relative distance
is now 1900km, velocity 2.35m/s
6 June
LIDAR was powered on after 2 year long crusing to check its health. We did it step by step, Each command response needs 32
minutes for confirmation. Altogether it took us 5 hours to complete this checking. We cannot use it yet as the distance is still too
large for the LIDAR.
P
QUOTE (pandaneko @ Jun 9 2018, 02:07 PM)
accelerated Hayabusa 2 by 24cm/s in minus X
Misleading translation? It looks like H2 actually slowed down:
https://aliveuniverse.today/rubriche/missio...proccio-a-ryugu
Probably a matter of frames of reference. The spacecraft needs to match speed with the asteroid in orbit around the Sun. Speeding up slightly in its orbit around the Sun might reduce its velocity with respect to Ryugu. I don't know the details, but that is most likely what is going on.
Phil
Phil
For clarification of the cordinate system I refer to page 16 of JAXA FACT sheet ver2.0, dated 19 April.
-X direction: where star tracker is pointing, as well as the re-entry capsule
-Y direction: where ONC-W2 is pointing, W2 is looking perpendicular to star tracker direction
+Y direction: where ion engines are pointing
+Z direction: is the direction of the earth because I can see two Ka band disk anntenae are pointing and it is opposit to
-Z direction: where sampler horn is pointing
My guess is that ONC-W2 is the donation camera.
P
-X direction: where star tracker is pointing, as well as the re-entry capsule
-Y direction: where ONC-W2 is pointing, W2 is looking perpendicular to star tracker direction
+Y direction: where ion engines are pointing
+Z direction: is the direction of the earth because I can see two Ka band disk anntenae are pointing and it is opposit to
-Z direction: where sampler horn is pointing
My guess is that ONC-W2 is the donation camera.
P
QUOTE (Phil Stooke @ Jun 10 2018, 05:19 AM)
Probably a matter of frames of reference. The spacecraft needs to match speed with the asteroid in orbit around the Sun. Speeding up slightly in its orbit around the Sun might reduce its velocity with respect to Ryugu. I don't know the details, but that is most likely what is going on.
Phil
Phil
This perhaps has something to do with my earlier translation about acceleration.
"We are at the very last stage of navigation and we are firing the ion engines into the acceleration direction.
Consequently, there are times when HY2 speed increases momentarily (conversely, meaning a longer orbital
period in the longer run, leading to a decreased flight velocity, which is a very interesting aspect of orbital
dynamics)
As a result, matching of HY2 orbit and that of Ryugu becomes better and the relative distance between them
decreases."
P
I am not sure if this diagram reflects real situation, but it seems to me that at 1000km dishes will be pointing to us on earth
without having to turn the the satelite. Image size at 2500km was something like 3x3, so at 1000km we may be looking at
something like 50 pixels, and that may be something, no? Surely, JAXA will be tempted to take a few photos, no?
P
without having to turn the the satelite. Image size at 2500km was something like 3x3, so at 1000km we may be looking at
something like 50 pixels, and that may be something, no? Surely, JAXA will be tempted to take a few photos, no?
P
I'm sure they will for navigational purposes, but they may not be of much interest otherwise. Should provide a crude approximation of the shape, though.
TCM-2 done at 1300km, no more sideway thrusts needed. Ryugu is right in front of Hayabusa 2.
P
P
I want to see satelites around Ryugu, just one will do...
P
P
JAXA released another image of Ryugu, now from 1500 km away, taken yesterday. Still can't discern a shape, but it's now at -5.7 magnitude:
The latest image is over-exposed (or at least, processed to clip the histogram), rather than 'very bright' as the report suggests. But it's not completely washed out. There is a tiny bit of variation in the bright pixels. So maybe these are the first hints of surface features! Here's a version of the image processed to show the detail. Now, it could still be true that this is an artifact, but based on past experience with first glimpses of new worlds, I think it may be real. The dark spot is not completely symmetrical.
Phil
Click to view attachment
Phil
Click to view attachment
QUOTE (Phil Stooke @ Jun 11 2018, 06:49 PM)
The latest image is over-exposed (or at least, processed to clip the histogram)
The shot lasted 178 seconds w.r.t. 0.090 of the darker one.
I have not actually seen any of the staions in action before, but here it is. Apparently they had been at it for half an hour when
I opened the Haya2 web page. Thank yo, Goldstone!!!
P
I opened the Haya2 web page. Thank yo, Goldstone!!!
P
Tyring to find out where Hayabusa 2 will be after return to the earth I searched i vain for clues in JAXA Facts sheet of April this year, and
I could not find anything there. Instead, I came across a few interesting remarks about Hayabusa 2 itself.
Not exactly completely new discoveries to many of us here, but I will carry them soon, becaiuse after all it is still popcorn time before
the main film starts, I think... and also, some people here must be very busy to notice minor things.
Here again, I really wish there were a few mini mini satelites around Ryugu, small ones, like bascket ball size... They will be cute!
P
I could not find anything there. Instead, I came across a few interesting remarks about Hayabusa 2 itself.
Not exactly completely new discoveries to many of us here, but I will carry them soon, becaiuse after all it is still popcorn time before
the main film starts, I think... and also, some people here must be very busy to notice minor things.
Here again, I really wish there were a few mini mini satelites around Ryugu, small ones, like bascket ball size... They will be cute!
P
The darker patch in the middle is a volcano?
P
P
QUOTE (pandaneko @ Jun 12 2018, 09:09 AM)
Here again, I really wish there were a few mini mini satelites around Ryugu, small ones, like bascket ball size... They will be cute!
I was just thinking about this: won't the SCI impact create a persistent cloud of debris orbiting around Ryugu? I think not all of the fragments will cross escape velocity.
Ore, there is maybe another possibility: rather than creating a crater, a 2kg copper bullet (around 6x6x6 cm) shot at 2 km/s could pass through the whole asteroid, if it is just a "pile of rubble" with almost no gravity to keep pebbles and sand and ice together...
I have been wondering how, from the plane on which ONC-W2 is located, on earth W2 can view anything of Ryugu and I have found
an answer to that. W2 is the donation camera. W2 can look down, not vertically downward, but at an angle. See the diagram!
P
an answer to that. W2 is the donation camera. W2 can look down, not vertically downward, but at an angle. See the diagram!
P
QUOTE (pandaneko @ Jun 12 2018, 02:14 PM)
I have been wondering how, from the plane on which ONC-W2 is located, on earth W2 can view anything of Ryugu and I have found
an answer to that. W2 is the donation camera. W2 can look down, not vertically downward, but at an angle. See the diagram!
P
an answer to that. W2 is the donation camera. W2 can look down, not vertically downward, but at an angle. See the diagram!
P
Very interesting and detailed video about all the cameras (visible, IR) onboard, with 3d visualizations of FOVs:
https://www.youtube.com/watch?v=LFh_pe3O_xM
"The darker patch in the middle is a volcano?"
Pandaneko, see the earlier post - you can't tell what something is unless there are many pixels across it. Here, one pixel is very slightly darker than those around it. Probably there is a small dark spot inside that pixel - a dark marking or shadow - much smaller than the pixel but big enough to make it, on average, a bit darker. No interpretation is possible yet. And my dark marking MIGHT just be an artifact. I think it's not but it might be.
But this is a testable hypothesis. When we get closer, and can see clearly, and know how the asteroid rotates, we will be able to figure out which bit of the asteroid was facing the camera when this image was taken. Then we can see if this is real or not.
(also - tiny rocks don't have volcanoes)
Phil
Pandaneko, see the earlier post - you can't tell what something is unless there are many pixels across it. Here, one pixel is very slightly darker than those around it. Probably there is a small dark spot inside that pixel - a dark marking or shadow - much smaller than the pixel but big enough to make it, on average, a bit darker. No interpretation is possible yet. And my dark marking MIGHT just be an artifact. I think it's not but it might be.
But this is a testable hypothesis. When we get closer, and can see clearly, and know how the asteroid rotates, we will be able to figure out which bit of the asteroid was facing the camera when this image was taken. Then we can see if this is real or not.
(also - tiny rocks don't have volcanoes)
Phil
This is the BIGGESTof the rovers/landers, MASCOT.
Minerva-II rover B is half this size, Minerva-II rovers A1 and A2 are quarter this size!!
https://www.youtube.com/watch?v=DbLmmvki_Bo
Minerva-II rover B is half this size, Minerva-II rovers A1 and A2 are quarter this size!!
https://www.youtube.com/watch?v=DbLmmvki_Bo
On Hayabusa 2 main web page the flight path is horizontally exergerated 10 times for emphasis. There is a caption to that effect
on the same diagram.
P
on the same diagram.
P
Why is it that flight path segments are not straight?
P
P
QUOTE
We're now less than 1000km from Ryugu! The asteroid is so close, we've had to change our website header so you can see the approach trajectory: the horizontal scale is now 10 x larger than the vertical scale.
https://twitter.com/haya2e_jaxa/status/1006669149832077312
QUOTE (pandaneko @ Jun 13 2018, 02:23 AM)
Why is it that flight path segments are not straight?
Flight path corrections? (Oh, if you are referring to the arch shape of the sections, given the complexities of orbital dynamics which I understand not at all, I'm surprised they are not some wierd corkscrew shape!)
What follows are the minor points I discovered on Hayabusa 2 Fact sheet of April
1. Chemical thrusters:
From lessons learnt from the failure with Akatsuki and Hayabusa piping system has been improved
2. Target marker is now 5 instead of 3 with Hayabusa. The idea of non-bouncing target markers comes from traditional Japanese toy
for girls called "Otedama". See still photos and a short movie. Edible beans are contained in these cloth wrapped objects.
https://goo.gl/XzawBr still pictures
https://www.youtube.com/watch?v=RHDwIL6CAIc short movie
3. Stay length: 18 months instead of 3 months with Hayabusa.
4. Samplings: 2 from surface and 1 from impact site
5. LIDAR: Not just a range finder, also finds topology, gravity, albido(spelling uncertain), range is 30m to 25km
6. ONC-W2 (donation camera) has the same specs as ONC-W1, 1mm/pix at 1m height
7. Rare gas sampling: Metal seal method so that rare gas can be brought back.
8. Sample containers: increased to three from two on Hayabusa
9. Sampling horn has an acute angle ring shaped gutter piece all around the opening so that 1-5mm grains can be accomodated
on touch down. Sudden stop in upward motion may move them into sample containers.
10. DCAM: Low resolution but real time analogue camera and high resolutioon digital camera. They are completely seperate systems
on DCAM. Battery life is 3 hours and comms. range is 10km.
11. Simultaneous interferrometric measurements of Hayabusa 2 position
Japan-Goldstone (east-west) and Japan-Cambbera (north-south) as the base lines greatly contributed to the co-ordinate accuracy
of Hayabusa 2
P
1. Chemical thrusters:
From lessons learnt from the failure with Akatsuki and Hayabusa piping system has been improved
2. Target marker is now 5 instead of 3 with Hayabusa. The idea of non-bouncing target markers comes from traditional Japanese toy
for girls called "Otedama". See still photos and a short movie. Edible beans are contained in these cloth wrapped objects.
https://goo.gl/XzawBr still pictures
https://www.youtube.com/watch?v=RHDwIL6CAIc short movie
3. Stay length: 18 months instead of 3 months with Hayabusa.
4. Samplings: 2 from surface and 1 from impact site
5. LIDAR: Not just a range finder, also finds topology, gravity, albido(spelling uncertain), range is 30m to 25km
6. ONC-W2 (donation camera) has the same specs as ONC-W1, 1mm/pix at 1m height
7. Rare gas sampling: Metal seal method so that rare gas can be brought back.
8. Sample containers: increased to three from two on Hayabusa
9. Sampling horn has an acute angle ring shaped gutter piece all around the opening so that 1-5mm grains can be accomodated
on touch down. Sudden stop in upward motion may move them into sample containers.
10. DCAM: Low resolution but real time analogue camera and high resolutioon digital camera. They are completely seperate systems
on DCAM. Battery life is 3 hours and comms. range is 10km.
11. Simultaneous interferrometric measurements of Hayabusa 2 position
Japan-Goldstone (east-west) and Japan-Cambbera (north-south) as the base lines greatly contributed to the co-ordinate accuracy
of Hayabusa 2
P
They have changed the display appearance of the flight path on Hayabusa 2 main page to suit the actual display in their control room.
P
P
After examining source code of JAXA page, I found this raw data file about Hayabusa position:
http://www.hayabusa2.jaxa.jp/hy2sc2/data/hy2_trj.txt
I don't know if "data before today" are real recorded data, or if all of these data are just simulated...
Also found these data for Ryugu, in case anyone is interested:
HY2TRJ.Storage.Ryugu = new Orb.Kepler({
"gm": 2.9591220828559093*Math.pow(10,-4),
"argument_of_periapsis":211.4366,
"eccentricity":0.1902973,
"epoch":2458200.5,
"inclination":5.88397,
"longitude_of_ascending_node":251.58914,
"mean_anomaly":305.97003,
"semi_major_axis":1.1895874
It would be interesting to check if both data groups will be updated in next days.
http://www.hayabusa2.jaxa.jp/hy2sc2/data/hy2_trj.txt
I don't know if "data before today" are real recorded data, or if all of these data are just simulated...
Also found these data for Ryugu, in case anyone is interested:
HY2TRJ.Storage.Ryugu = new Orb.Kepler({
"gm": 2.9591220828559093*Math.pow(10,-4),
"argument_of_periapsis":211.4366,
"eccentricity":0.1902973,
"epoch":2458200.5,
"inclination":5.88397,
"longitude_of_ascending_node":251.58914,
"mean_anomaly":305.97003,
"semi_major_axis":1.1895874
It would be interesting to check if both data groups will be updated in next days.
By the look of it next straight ahead is at around 600km when Hayabusa 2 becomes tangential to its planned
flight path. I am running out of my popcorn...
P
flight path. I am running out of my popcorn...
P
From press conference
Click to view attachment
Click to view attachment
Ryugu seems quite similar to the anticipated shape model.
If the Sun was right behind the ship, it seems that there is a brighter area on the right and a darker one on the left. But these can be artifacts
If the Sun was right behind the ship, it seems that there is a brighter area on the right and a darker one on the left. But these can be artifacts
New press conference held yesterday.
https://www.youtube.com/watch?v=S9nw3bli_Io&t=33s
Presentation in Japanese, lot of veryu interesting info! (Probably English version is coming soon)
http://fanfun.jaxa.jp/jaxatv/files/20180614_hayabusa2.pdf
https://www.youtube.com/watch?v=S9nw3bli_Io&t=33s
Presentation in Japanese, lot of veryu interesting info! (Probably English version is coming soon)
http://fanfun.jaxa.jp/jaxatv/files/20180614_hayabusa2.pdf
QUOTE (mcmcmc @ Jun 14 2018, 07:34 AM)
New press conference held yesterday.
https://www.youtube.com/watch?v=S9nw3bli_Io&t=33s
Presentation in Japanese, lot of veryu interesting info! (Probably English version is coming soon)
http://fanfun.jaxa.jp/jaxatv/files/20180614_hayabusa2.pdf
https://www.youtube.com/watch?v=S9nw3bli_Io&t=33s
Presentation in Japanese, lot of veryu interesting info! (Probably English version is coming soon)
http://fanfun.jaxa.jp/jaxatv/files/20180614_hayabusa2.pdf
Google Translate seems to do a good job translating each slide.
One slide says the image of the asteroid is now 10 pixels across, was 3.
QUOTE (MahFL @ Jun 14 2018, 09:41 AM)
Google Translate seems to do a good job translating each slide.
One slide says the image of the asteroid is now 10 pixels across, was 3.
One slide says the image of the asteroid is now 10 pixels across, was 3.
Last time I spent hours in copying each slide in google and translating... then the day after they issued the english version.
So I'll wait. :-)
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.