Dawn Framing Camera Q&A, Ask your questions to the Framing Camera Operations Team |
Dawn Framing Camera Q&A, Ask your questions to the Framing Camera Operations Team |
Jul 1 2011, 04:36 PM
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#16
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Junior Member Group: Members Posts: 22 Joined: 6-March 10 From: London, Ontario, CANADA Member No.: 5247 |
Hallo and welcome, Pablo!
That post on Dawn FC team organization and activity is gold! Almost puts us there... Good luck with the coming weeks & months, and thanks for volunteering to be the liasion. ...This is a good time to be alive! -pjam -------------------- "We absolutely must leave room for doubt or there is no progress and there is no learning." -Richard P. Feynman
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Jul 1 2011, 05:29 PM
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#17
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Director of Galilean Photography Group: Members Posts: 896 Joined: 15-July 04 From: Austin, TX Member No.: 93 |
Have you guys solved any interesting problems?
As an engineer myself, I like hearing about "war stories" from others. Once recent one for me was customers returning boards because they couldn't program the flash and it turned out that we had purchased these NAND flashes from brokers (kinda grey-market-ish), and when we scanned them, we found text strings like "Discovery Channel, Disney, etc". Apparently they were originally programmed for a set-top box and were remaindered, and our manufacturing program didn't erase them, because the spec for the NAND said they would come erased. Whoops! Then there's the story about the chip that wouldn't boot properly the second time you powered it on, because a certain power rail decayed so slowly that 3 seconds after power off, it was still a couple of hundred millivolts, and when the processor turned on, it corrupted the internal state enough to cause a crash. That one was a real head-scratcher for me, first time I'd seen a problem caused by a power supply not powering down fast enough! -------------------- Space Enthusiast Richard Hendricks
-- "The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C Clarke Mother Nature is the final inspector of all quality. |
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Jul 2 2011, 08:24 AM
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#18
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Senior Member Group: Members Posts: 3516 Joined: 4-November 05 From: North Wales Member No.: 542 |
Concerning the work of the amateurs, we are simply amazed at the dedication you put into this hobby, and indeed we are considering getting in touch with some of the contributor to evaluate possible collaborations. Seeing what's been happening with the latest image that looks like a very good idea. Seriously, I'd like to add my heartfelt thanks to you for letting us all 'inside' the Dawn mission as far as your remit allows. I hope that the resulting positive experience on both sides will continue to move mission management towards a more Cassini-like image release policy. |
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Jul 2 2011, 09:43 PM
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#19
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Junior Member Group: Members Posts: 50 Joined: 27-June 11 From: Katlenburg-Lindau, Lower Saxony, Germany Member No.: 6038 |
Have you guys solved any interesting problems? It is a general rule of politeness, that one should not talk about the war while it is still going on, but since Marc Rayman, the mission engineer, already talked about it in the mission blog, I would like to call your attention about the intelligent solution that the mission team envisioned to save the propellent hydrazine. Regards, Pablo -------------------- |
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Jul 2 2011, 09:49 PM
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#20
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Junior Member Group: Members Posts: 50 Joined: 27-June 11 From: Katlenburg-Lindau, Lower Saxony, Germany Member No.: 6038 |
Hola, Pablo. Will you attempt to use superresolution on interesting targets? Hola Fran I am afraid that you question falls more on the side of scientific analysis software than on the operations, but I will try to answer it. The observation plan for the High Altitude Mapping Orbit (HAMO) already includes several views of each spot from different angles, that can provide sub-pixel resolution on the topographic model. I hope this answers your question. Regards, Pablo -------------------- |
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Jul 2 2011, 10:00 PM
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#21
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Junior Member Group: Members Posts: 70 Joined: 12-November 06 Member No.: 1354 |
Ah, I see on the Dawn site that, in order to take Nav photos, the spacecraft has to stop thrusting. That would certainly explain the paltry number of pictures we have seen to date. Do you have a timeline of the number of Nav photo attempts planned for the next couple of weeks, Pablo?
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Jul 2 2011, 10:04 PM
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#22
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Solar System Cartographer Group: Members Posts: 10153 Joined: 5-April 05 From: Canada Member No.: 227 |
If I may borrow this space to reply to Fran, even if super-resolution is not a goal of an imaging sequence, there will be opportunities to use it every time a multispectral image sequence is obtained. If a set of images are taken in quick succession through different filters, they can be combined to make a super-resolution composite. I have done this with Voyager images of Hyperion, for example. If there is a lot of colour variation in a scene, as we see on Io, this will not work, but for scenes with only minor colour variation it will be OK, and that will be true for Vesta.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Jul 2 2011, 11:03 PM
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#23
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Junior Member Group: Members Posts: 50 Joined: 27-June 11 From: Katlenburg-Lindau, Lower Saxony, Germany Member No.: 6038 |
Do you have a timeline of the number of Nav photo attempts planned for the next couple of weeks, Pablo? Hi Norm, The plan for this approach phase was to start by acquiring OpNav images once per week for the first 6 weeks and then change to twice per week, which is the rate that we currently have. Regards, Pablo -------------------- |
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Jul 3 2011, 03:21 AM
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#24
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Member Group: Members Posts: 293 Joined: 22-September 08 From: Spain Member No.: 4350 |
there will be opportunities to use it every time a multispectral image sequence is obtained. Thanks. I wonder if the backup camera can be operated at the same time as the main, and if the team would get a waiver to do so at Ceres after the end of the primary mission. |
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Jul 4 2011, 10:10 AM
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#25
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Junior Member Group: Members Posts: 50 Joined: 27-June 11 From: Katlenburg-Lindau, Lower Saxony, Germany Member No.: 6038 |
Thanks. I wonder if the backup camera can be operated at the same time as the main, and if the team would get a waiver to do so at Ceres after the end of the primary mission. Hi Fran, Yes, both cameras can operate concurrently and indeed, they have done so in the past... on ground. Currently there are no plans ot use both cameras concurrently and we have seen no reason to do so, but if you have a suggestions, please do not hesitate to speak up. Regards, Pablo -------------------- |
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Jul 4 2011, 01:43 PM
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#26
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IMG to PNG GOD Group: Moderator Posts: 2250 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
Welcome to UMSF!
I have a few questions: How many images do you expect to obtain while orbiting Vesta? Are some/all of the images compressed aboard the spacecraft before they are downlinked and if so is the compression lossy or lossless? One day I was looking at the newly arrived images and, when my office mate asked me if he should fetch the rest of the team, all I could say was: "Give me just one minute to enjoy the images alone, and then you can get the team". This is a familar feeling to me in a slightly different context though. There's something special about seeing a 'new' world clearly for the first time. |
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Jul 5 2011, 09:59 AM
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#27
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Junior Member Group: Members Posts: 50 Joined: 27-June 11 From: Katlenburg-Lindau, Lower Saxony, Germany Member No.: 6038 |
Are some/all of the images compressed aboard the spacecraft before they are downlinked and if so is the compression lossy or lossless? Hi Bjorn, It is out of discussion that, once you launch a mission into space, you have already made the biggest expense, so the way to get a return for this is getting science of the data. The overall data volume transmitted from the spacecraft has a significant impact in the DSN usage costs, so try to minimize the volume as long as it does not impact the science quality. This is why all the images we transmit are compressed, but loss-less. Later in the mission, there will be phases were certain types of images will be considered sub-prime and will therefore be compressed with loss. These will be images intended to provide a background but not worthy from the science point of view. Regards, Pablo -------------------- |
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Jul 7 2011, 02:58 PM
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#28
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Member Group: Members Posts: 293 Joined: 22-September 08 From: Spain Member No.: 4350 |
we have seen no reason to do so, but if you have a suggestions, please do not hesitate to speak up. Perhaps to add them if a longer single exposure would suffer from smear. Another question: is there a priority to capture and download first certain filters? Particulary clear, versus the ones more suitable for RGB, versus the ones suitable for trippy science color. |
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Jul 9 2011, 10:30 PM
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#29
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Junior Member Group: Members Posts: 50 Joined: 27-June 11 From: Katlenburg-Lindau, Lower Saxony, Germany Member No.: 6038 |
Another question: is there a priority to capture and download first certain filters? Particulary clear, versus the ones more suitable for RGB, versus the ones suitable for trippy science color. Yes, the camera implements a download priority scheme in four levels. The top priority is given to images acquired for the purpose of optical navigation (OpNav), like most of the images that we are acquiring now during the approach phase. The other three priorities are assigned to the different image acquisition depending on the purpose of a particular observation. To all: I am now on vacation in Spain, so I have limited access to internet. Please be patient in case it takes me a couple of days to answer your questions. -------------------- |
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Jul 9 2011, 10:39 PM
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#30
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Senior Member Group: Members Posts: 1018 Joined: 29-November 05 From: Seattle, WA, USA Member No.: 590 |
How long does the camera take to make a picture?
--Greg |
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