Mission: Hayabusa 2 |
Mission: Hayabusa 2 |
Oct 8 2018, 02:36 PM
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#601
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Member Group: Members Posts: 120 Joined: 26-May 15 From: Rome - Italy Member No.: 7482 |
I do not know if this question has already been done. I can not understand the temperature in Ryugu's color scale. What does 4000/-2000 mean? these are not C°. F. K.?
The site is unclear simply writes:" High temperatures on the asteroid reach 100°C, while the coldest regions sit at about room temperature. Temperatures also change depending on the solar distance of the asteroid". http://www.hayabusa2.jaxa.jp/en/topics/20180907e/ |
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Oct 8 2018, 02:52 PM
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#602
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Senior Member Group: Members Posts: 4246 Joined: 17-January 05 Member No.: 152 |
The caption reads "The scale bar shows relative temperature (the values have no meaning)." So it sounds like this is some temperature-dependent signal (intensity at some wavelength?) that hasn't yet been (or won't or can't be) converted to temperature. You can perhaps very crudely estimate temperatures based on that stated range (ie, deepest red ~ 100 C, deepest blue ~ 20 C), but there's no guarantee that is accurate or that the colour scale is linearly proportional to temperature in between those limits.
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Guest_mcmcmc_* |
Oct 10 2018, 07:28 AM
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#603
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Guests |
Unfortunately thermal cameras have no an absolute scale: they draw in blu the coldest thing they see and in white or red the hottest thing... but right in that moment! When the subject changes or move... blu is still the coldest point and whitethe hottest, but they can mean different absolute temperatures.
So in one image you could have blue=0°C and red/white=+100°C, but in another image you could have blue=-100°C and white=-50°C (different extreme values and different range). I don't know how you can calibrate them, especially if you have no references with known temperatures in the image. |
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Oct 10 2018, 11:17 PM
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#604
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
Here is the most accurate description I found about the thermal infrared imager (TIR). See subsection 5.4 for the temperature accuracy.
The instrument is built on the basis of an uncooled NEC 320A bolometer. Be aware, that these instruments usually measure brightness temperatures. |
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Oct 11 2018, 02:59 AM
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#605
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Senior Member Group: Members Posts: 1419 Joined: 26-July 08 Member No.: 4270 |
Press Conference in 2.5 hours (as of the time of this post).
https://www.youtube.com/watch?v=zXXepYfsiQc -------------------- -- Hungry4info (Sirius_Alpha)
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Oct 11 2018, 06:53 AM
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#606
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Member Group: Members Posts: 435 Joined: 14-December 15 Member No.: 7860 |
Press Conference in 2.5 hours (as of the time of this post). https://www.youtube.com/watch?v=zXXepYfsiQc today's press conference pdf in japanese http://fanfun.jaxa.jp/jaxatv/files/20181011_hayabusa2.pdf. There are no new pictures |
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Oct 11 2018, 08:48 PM
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#607
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Member Group: Members Posts: 362 Joined: 12-June 05 From: Kiama, Australia Member No.: 409 |
Japan delays touchdown of Hayabusa2 probe on asteroid: official
http://www.spacedaily.com/m/reports/Japan_...ficial_999.html JAXA project manager Yuichi Tsuda said they needed more time to prepare the landing as the latest data showed the asteroid surface was more rugged than expected. |
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Oct 11 2018, 09:41 PM
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#608
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Senior Member Group: Members Posts: 2511 Joined: 13-September 05 Member No.: 497 |
I don't know how you can calibrate them... Pretty much the same way you calibrate anything, you use calibrated blackbody sources of known temperatures and then you assume the camera stays stable over operating conditions, or you calibrate it over those conditions in ground testing. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Oct 12 2018, 04:56 AM
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#609
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Member Group: Members Posts: 817 Joined: 17-April 10 From: Kamakura, Japan Member No.: 5323 |
I could not upload my translation all last two days. Screen just kept jittering. Anyway, some of the new things in the press briefing are
as follows: p6 We were engaged in MASCOT seperation from 30 September to 4 October and MASCOT was successfully seperated on 3 October and it landed on the asteroid and functioned for about 17 hours. Rehearsal (again) for the 1st touch down (TD1-R1-A) will be conducted from 14 to 15 October. p7 Operation outline On 28 September we receivded in writing, from Dr Tra-MiHo, project manager of MASCOT, her order to seperate MASCOT from the mothership. As a result, on 2 Octber at 11:50 (JST) a command was sent to Hayabusa 2 to start descending and at 10:57:20 on 3 October MASCOT was seperated at a height of 51m. We received from Dr Tra-MiHo at 04:30 on 4 October her declaration of the completion of this mission. MASCOT functined for about 17 hours and all instruments on board obtained data. The data was then sent to the team in Germany. It has been confirmed that MASCOT did one hopping. MASCOT operation was entirely conducted at the German end and about 40 people were involved at DLR and 5 people at CNES supported this operation. US support with DSN came at level 2 (redundant antenna plus maximum manpower support) Received data will be used for touch down operation as well p15 6 descending operations have been conducted by now. As a direct result of these operations following schedule has been agreed on. TD1-R1-A(2nd TD rehearsal) on 14-15 October. TD1-R3(3rd TD rehearsal) on 24-25 October. Late November to December overall operation. 1st touch down after January 2019. p17 TD1-R1 was made to equatorial zone, MINERVA-II northern hemisphere, and MASCOT middle lattitude area of southern hemisphere. From these operations it is now known that H2 can be guided to +/-30 degrees from the equator and with an accuracy of +/-10m down to the height of about 50m. P18 From observations we find that TD candidate areas (L08,L07,M04)are densely covered by boulders( larger than 50cm). Their distribution has been obtained. TD areas are found to be very difficult to land with so many boulders. P19 From the photos that have been taken by MINERVA and MASCOT Ryugu's surface is not that of a few boulders sitting here and there on sandy ground, but it is rather that the ground itself is made up of boulders. Some more to follow. P |
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Oct 12 2018, 05:55 AM
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#610
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Member Group: Members Posts: 817 Joined: 17-April 10 From: Kamakura, Japan Member No.: 5323 |
Press briefing findings
p20 Touch down rehearsal and policy Things that need confirmation 1. confirm that we can combat an extremely rough terrain. 2. confirm spacecraft behaviour at an extremely low altitude below 50m. 3. Confirm navigation precision below 50m via TD1-R1-A 4. cinfirm LRF properties via TD1-R1-A 5. Target markers tracking properties, if possible via TD1-R3 operation ※TM in our earlier project plan target marker tracking was not part of it, but it was decided to add this operation in our new plan. In addition we may also consider pin point touch down. NB: Target marker tracking(TMT) Markers are identified within photos and positions are reflected into orbt controling. What is wanted in TD1-R1-A : Confirmation of control precision. LRF properties. NB: with LRF only measurments will be taken and they are not immediately used for actual controling. What is wanted in TD-R3: Confirmation of control precision Incorporate LRF measurments into control programme If possible release target markers P21 Rehearsals 14-15 October: TD1-R1-A (2nd touch down rehearsal) 24-25 October: TD1-R3 (3rd touch down rehearsal) Press briefings 16:00 23 October 11:00 8 November End of this briefing P |
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Guest_mcmcmc_* |
Oct 12 2018, 07:40 AM
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#611
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Guests |
Just in time for next mission, here it is a fully functional simulator:
https://programmi.000webhostapp.com/hayabus...simulator3.html Changes: Added speed to realtime data Added speed to history chart Moved/resized ryugu/H2 schematic Added decimals to rovers images sizes in ONC (Invisible: added speed data to history log) Plans for the future: Add a box with a zoom of the chart on last 72 hours. Add a box with a zoom of the chart between 0 and 500 meters (or configurable). Add the schedule for next missions. Add playback function for previous missions; in the meantime you can use separate pages to perform a replay of MINERVA release mission and MASCOT release mission. Players are still in beta so pay attention not to move mouse over images until they are fully loaded or they will stop loading. Next missions: 14-15 October: TD1-R1-A (2nd touch down rehearsal) 24-25 October: TD1-R3 (3rd touch down rehearsal) Next press conferences: 23 October-16:00 JST (07:00GMT) 8 November - 11:00 JST (02:00 GMT) |
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Oct 13 2018, 01:34 PM
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#612
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Member Group: Members Posts: 817 Joined: 17-April 10 From: Kamakura, Japan Member No.: 5323 |
I was watching the last and latest press briefing once again and I noticed that my earlier translation needs improvements.
TD1-R1-A: This is exactly the same operation as the very first rehearsal, which was aborted due to LIDAR not feeling very well.They are will be trying to repeat the same operation. TD1-R3 : This is a new rehearsal based on the findings of TD1-R1A (JAXA said that this operation could be named as TD-R2). During Late November to December H2 will be hidden behind the Sun, so other operations will be running. And, by far the most important is that the first touch down operation will be delayed into the latter half of January 2019, simply because the surface is so violently rocky. P |
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Oct 14 2018, 07:08 AM
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#613
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Newbie Group: Members Posts: 17 Joined: 15-August 15 Member No.: 7722 |
There is new press release by DLR with some new images and details about MASCOT landing:
Numerous boulders, many rocks, no dust: MASCOT's zigzag course across the asteroid Ryugu mcmcmc: That is very nice simulator! Thank you for that : ) |
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Oct 15 2018, 04:59 AM
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#614
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Newbie Group: Members Posts: 14 Joined: 30-September 14 Member No.: 7269 |
https://twitter.com/haya2e_jaxa/status/1051693960429633537
HAYABUSA2@JAXA @haya2e_jaxa The material from the press briefing that was held on October 11 is now available on the project website. Content includes: (1) Report on the separation of MASCOT, (2) Touchdown rehearsals and plans. http://www.hayabusa2.jaxa.jp/en/enjoy/mate...1011_ver7en.pdf 13:39 - 2018年10月15日 |
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Guest_mcmcmc_* |
Oct 15 2018, 06:40 AM
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#615
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Guests |
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. But please note that most of the released images are form ONC-W, which has 1/10 resolution of ONC-T. |
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