Mission: Hayabusa 2 |
Mission: Hayabusa 2 |
Jun 23 2018, 04:29 AM
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#376
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Senior Member Group: Members Posts: 1419 Joined: 26-July 08 Member No.: 4270 |
If my math is right, assuming a radius of 450 metres, Ryugu needs a density of at least ~0.26 g cm-3 to have a Hill sphere out to Hayabusa 2's distance. So that sounds plausible.
Edit: Apparently that's what the mission team thinks too. https://twitter.com/haya2_jaxa/status/1009368813429592064 QUOTE From now on, the gravity of the asteroid will dominate the area (Hill area: Within about 90km from the asteroid)!
-------------------- -- Hungry4info (Sirius_Alpha)
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Jun 23 2018, 08:55 AM
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#377
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Newbie Group: Members Posts: 17 Joined: 15-August 15 Member No.: 7722 |
They are definitely in Ryugu's sphere of influence... the last maneouevre brought the velocity to 9 cm per second, and over the last day or so it accelerated to 10 and now 11 cm/s. That has to be the asteroid's gravity giving a slight speed boost, right? There is also acceleration due to solar radiation pressure which has to be accounted for. Other effects (like Coriolis force and gravity of other bodies) should be negligible or not relevant at this point. |
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Guest_mcmcmc_* |
Jun 24 2018, 09:31 AM
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#378
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Guests |
TCM08 confirmed but different from planned:
QUOTE Our 8th Trajectory Control Manoeuvre (TMC08) for optical navigation was made on June 24, 2018 from ~09:30-09:40 JST. Trusters gave a velocity change of ~0.2cm/3 (+y), 2cm/s (+z). The distance to Ryugu from Hayabusa2 was 38km & the relative speed after TCM08 was ~0.08 m/s (8 cm/s) https://twitter.com/haya2e_jaxa/status/1010759732515098625 Planned: 58293,013888 2018/06/24T00:20:00,0 -0,0541 0,1376 27,1238 0,001939 -0,002281 -0,123958 58293,020833 2018/06/24T00:30:00,0 -0,0529 0,1363 27,0494 0,002306 -0,000590 -0,010717 Actual: 58293.018055 2018/06/24T00:26:00.0 -0.1998 0.2395 38.3500 0.002254 -0.002601 -0.106281 58293.025000 2018/06/24T00:36:00.0 -0.1991 0.2386 38.2940 0.000540 -0.000687 -0.084732 Hence, new TCM added on 26/6: 58295.045833 2018/06/26T01:06:00.0 -0.1652 0.0514 21.0219 0.000191 -0.001503 -0.114487 58295.052777 2018/06/26T01:16:00.0 -0.1638 0.0508 20.9933 0.003624 -0.000580 -0.003281 Final TCM on 27/7 as planned: 58296.018055 2018/06/27T00:26:00.0 -0.0001 0.0002 20.0049 0.000394 -0.000642 -0.020535 58296.025000 2018/06/27T00:36:00.0 0.0000 -0.0000 20.0001 0.000022 0.000000 0.000111 (but actually after TCM08bis the speed will bealready just 3 mm/s) No new images yet. No English translation of latest press release yet: http://www.hayabusa2.jaxa.jp/topics/press/ |
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Jun 24 2018, 09:57 AM
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#379
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Member Group: Members Posts: 817 Joined: 17-April 10 From: Kamakura, Japan Member No.: 5323 |
No new images yet. No English translation of latest press release yet: http://www.hayabusa2.jaxa.jp/topics/press/ I hesitate to add what follows, but just in case.... P |
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Guest_mcmcmc_* |
Jun 24 2018, 10:21 AM
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#380
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Guests |
What is going to happen after Hayabusa flies down to next orbits (5km and 1km):
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Guest_mcmcmc_* |
Jun 24 2018, 10:33 AM
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#381
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Guests |
I hesitate to add what follows, but just in case.... P Yes but there is another one dated 21/6! http://fanfun.jaxa.jp/jaxatv/files/20180621_hayabusa2.pdf Only in Japanese! :-( |
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Guest_mcmcmc_* |
Jun 24 2018, 10:40 AM
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#382
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Guests |
Possible places for press releases:
http://global.jaxa.jp/projects/sat/hayabusa2/pdf/ http://fanfun.jaxa.jp/jaxatv/files/ http://www.hayabusa2.jaxa.jp/topics/press/doc/ Not browsable, but just add filename to download it: Japanese: 20150128_hayabusa2.pdf 20170712_hayabusa2.pdf 20171214_hayabusa2.pdf 20180419_hayabusa2.pdf 20180607_hayabusa2.pdf 20180614_hayabusa2.pdf 20180621_hayabusa2.pdf English: Hayabusa2_Press20180607e.pdf Hayabusa2_Press20180614e.pdf Hayabusa2_Press20180621e.pdf <<-- Where is it?!? |
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Jun 24 2018, 12:19 PM
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#383
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Member Group: Members Posts: 817 Joined: 17-April 10 From: Kamakura, Japan Member No.: 5323 |
Yes but there is another one dated 21/6! http://fanfun.jaxa.jp/jaxatv/files/20180621_hayabusa2.pdf Only in Japanese! :-( My guess is as follows. This document in Japanese dated 21 June does exist somewhere, but not yet archived. I dug into this FANFAN site and what follows is its URL. http://fanfun.jaxa.jp/countdown/hayabusa2/ and towards the end of all this you will see what is below. The latest that they carry here is not 21, but 14 June. So, although 21 June document exist on somebody's disk, but it has not been properly integrated into their listing database, let alone an English version. An English version may or may not exist. If it does exists it has not been listed properly on tbis FANFAN web site. That is my guess. P |
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Jun 25 2018, 06:41 AM
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#384
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Member Group: Members Posts: 817 Joined: 17-April 10 From: Kamakura, Japan Member No.: 5323 |
40km image, yes, lots and lots of craters. It must have been quite violent...
P |
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Jun 25 2018, 08:52 AM
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#385
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Member Group: Members Posts: 102 Joined: 29-January 10 From: Poland Member No.: 5205 |
-------------------- Adam Hurcewicz from Poland
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Guest_mcmcmc_* |
Jun 25 2018, 09:18 AM
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#386
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Guests |
First ONC-Wide photo!
We are just 27 km high now. |
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Guest_mcmcmc_* |
Jun 25 2018, 09:28 AM
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#387
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Jun 25 2018, 10:09 AM
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#388
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Member Group: Members Posts: 817 Joined: 17-April 10 From: Kamakura, Japan Member No.: 5323 |
No, this is no longer a puff fish. It very much looks like a pomegranate in my garden!
P |
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Jun 25 2018, 10:46 AM
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#389
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Junior Member Group: Members Posts: 22 Joined: 15-November 14 Member No.: 7320 |
I found the press release on youtube (or bto be honest: YT made me find it)
https://www.youtube.com/watch?v=tclBmsIh2yo Although I don't understnd anything, you can see the animated version of one of the slides in the presentation posted above, the simulated formation process. Q&A begins at about min. 20. @mcmcmc, where did you find that nice explosion gif, or is that yours? |
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Guest_mcmcmc_* |
Jun 25 2018, 11:57 AM
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#390
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Guests |
@mcmcmc, where did you find that nice explosion gif, or is that yours? I did the GIF by myself, using Trimble Sketchup 2017, SUalive plugin and the model downloaded from http://www.asahi.com/special/rocket/hayabu...ayabusa.obj.txt (rename to .obj), converted into .DAE format for import with texture in Sketchup (converted using Meshlab os Meshmixer or Netfabb, I don't remember which one eventually worked without errors). But you have to manually download the associated MTL file and the textures listed there. I'd like to redistribute the zip... but DeAgostini Japan is selling the buildable model for around 600$ and maybe they wouldn't like somebody to redistribute the 3d digital model... |
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