Author Topic: JAXA Hayabusa2 Mission : General Thread  (Read 245457 times)

Offline yoichi

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #280 on: 10/12/2018 09:33 am »
« Last Edit: 10/12/2018 12:10 pm by yoichi »

Offline yoichi

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #281 on: 10/14/2018 11:41 pm »
http://www.hayabusa2.jaxa.jp/en/topics/20181014e_TD/
Schedule change for the touchdown operation

http://www.hayabusa2.jaxa.jp/en/topics/20181014e_TD1-R1-A/
TD1-R1-A operation schedule

http://www.hayabusa2.jaxa.jp/en/galleries/onc/nav20181014/
Navigation Images from the TD1-R1-A operation (Real time delivery)




Offline mcgyver

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #284 on: 10/15/2018 06:42 am »
Follow realtime updates on the simulator (currently telemetries are updated by JAXA once every 10 minutes):
https://programmi.000webhostapp.com/hayabusa2/simulator/simulator3.html
https://programmi.000webhostapp.com/hayabusa2/simulator/haya2-dates.html

Theorical MASCOT size in ONC-T camera crossed 1 pixel, so it could be visible from now on, at least as a bright dot where no bright dots were visible before.
MINERVA rovers still around 0.6 pixel.


Anyway JAXA usually releases ONC-W camera images rather than ONC-T images; ONC-W has 1/10 resolution of ONC-T.
« Last Edit: 10/15/2018 06:45 am by mcgyver »

Offline mcgyver

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Offline mcgyver

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« Last Edit: 10/15/2018 08:54 am by mcgyver »

Offline yoichi

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« Last Edit: 10/15/2018 01:26 pm by yoichi »

Offline mcgyver

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #288 on: 10/15/2018 01:29 pm »
MASCOT rover now 1 pixel large in ONC-W camera.

Offline mcgyver

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #289 on: 10/15/2018 01:54 pm »
120 meters altitude, MINERVA rovers now 1 pixel wide in ONC-W.
2 pixel for MASCOT.
« Last Edit: 10/15/2018 01:54 pm by mcgyver »

Offline mcgyver

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #290 on: 10/15/2018 02:20 pm »
Simulator just crashed due to enexpected "0" value for calculated altitude; another value for altitude shows descent stop and ascent started, currently 132m from previous 61m.


Offline mcgyver

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #291 on: 10/15/2018 02:26 pm »
Jaxa simulator also in trouble, no more showing Ryugu schematic circle.
LIDAR reading 229m.
H2 raising at 0.6 m/s.
...probably ( ??? )


Raw data: http://haya2now.jp/data/data.json
LIDAR: RNG_LIDAR
Source for calculated altitude in my simulator and calculated ryugu diameter in Jaxa simulator: ONC_A






« Last Edit: 10/15/2018 02:26 pm by mcgyver »

Offline mcgyver

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #292 on: 10/15/2018 02:31 pm »

Offline mcgyver

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #293 on: 10/15/2018 02:35 pm »
Raising confirmed:
https://twitter.com/haya2e_jaxa/status/1051840541770440704
Did anything go wrong? I expected "low altitude navigation and Laser Range Finder testing".

Offline yoichi

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Offline mcgyver

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #295 on: 10/15/2018 03:52 pm »
https://twitter.com/haya2e_jaxa/status/1051850996173889537
I can't understand why they remained at such altitude for 2 seconds and then started an escape at ludicrous speed. Looks like an emergency command to save from crash, rather than a successful LRF testing or a "touchdown simulation"!
In last seconds H2 was still lowering altitude at 0.10cm/s rate, which means  over 200 meters in the 18+18 minutes between telemetry-on-earth and command-on-hayabusa instants.... which can be seen as the "equivalent" of 200 meters per second if you remove the time-delay from the equation.

Offline mcgyver

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #296 on: 10/15/2018 03:59 pm »
Altitude profile analysis and comparison to MASCOT mission;





« Last Edit: 10/15/2018 03:59 pm by mcgyver »

Offline mcgyver

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #297 on: 10/15/2018 04:04 pm »
...well, after all it looks like that raising at 0.70m/s was a scheduled operation... but I still don't understand how it can be called a "touchdown rehearsal", it looks more like a "touch&go", which is a totally different thing.
http://www.hayabusa2.jaxa.jp/en/topics/20181014e_TD1-R1-A/

Offline Phil Stooke

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #298 on: 10/15/2018 11:30 pm »
As the spacecraft descends, the asteroid is rotating.  You can't spend much time at an altitude of only 40 m in case a large rock or hill smacks right into you as the surface keeps moving.  So you rehearse the descent, making sure you can aim for the exact point you want, but then you get out quickly.  Part of the reason for a relatively rapid climb (it's still quite slow really) is that something could go wrong at any time and you have to get out while things are OK.

As I understand it the sampling will be like a touch and go, done very quickly.

Offline mcgyver

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Re: JAXA Hayabusa2 Mission : General Thread
« Reply #299 on: 10/16/2018 07:27 am »

As I understand it the sampling will be like a touch and go, done very quickly.
It would be interesting to find some documents about the procedure, maybe also from Hayabusa 1.


For a rotation period of 7.5 hours and a diameter of 900 m, the ground shift speed is around 0,10 m/s.
Rotation speed is 360°/7.5h = 48 °/h = 0.8 °/min = 0.013 °/sec

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