Author Topic: LIVE: Chang'e-3 lunar probe and rover Lunar Landing December 14, 2013  (Read 233892 times)

Offline Will

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It's almost as though they aren't entirely comfortable with freedom of information, for some reason.
They have different processes for publishing the data, slower than some NASA missions but not unheard of. They do publish the data, carefully and meticulously.
What I don't understand is: once they've sent data to national TV which also airs over internet, what else do they need to wait to release raw data?!?


Obviously for the same reason you're not satisfied with the TV grab, and are craving the raw images.
I wouldn't be surprised if some science communication / media organisation in China had access to the high-res versions first - (for a yet-to-be-aired documentary perhaps?) similar to proprietary access periods for scientific data. After all, Mars One's basing their business plan on that. Maybe China wanted to do a pilot with Chang'E 3?

Anyway..let's stop whining over this.. please?

Not whining, cobber. No huhu.  Just saying that China is slow to share original data compared to NASA and ESA.

Will

Offline pagheca

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Not whining, cobber. No huhu.  Just saying that China is slow to share original data compared to NASA and ESA.

I think this is quite understandable. They are still building up experience, they are not a democracy, they have to learn how to manage public outreach.

Scientists there are subject to scrutiny from the politicians and a single error may have quite strong impact on careers and funding. They have to learn step by step what you can do and when. They have had pretty big failures in the past and they may be scared by the possibility of a sudden failure live or of a misleading information given to the public.

Actually I'm amazed by seeing this coverage for this mission. Respect to the past it looks to me quite an improvement. Derivative matters, not absolute value.

« Last Edit: 12/22/2013 12:29 AM by pagheca »

Offline OzWill

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Finally, I think we have two photos not taken from the projection screen.

 Source

« Last Edit: 12/22/2013 05:22 AM by OzWill »

Offline Lars_J

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Nice!

One Q springs to mind - is the rover able to operate independently, out of visual range from the lander?
« Last Edit: 12/22/2013 06:00 AM by Lars_J »

Offline OzWill

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Two more interesting photos:

The lander one was captioned 'the first hot-fire test of chang'e 3 lander'.

Source

Offline OzWill

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Nice!

One Q springs to mind - is the rover able to operate independently, out of visual range from the lander?

Thanks to Emily Lakdawalla and her translation of a press briefing, seems like the rover can operate by itself.

Quote
Wu Weiren also talked about the rover having autonomous navigation capability. The Soviet Lunokhods required television monitors and continuous round-the-clock shifts of drivers to manually tele-operate them. Wu said that Yutu can be operated in this mode, but that there is also a "completely independent operation mode" in which it can be navigated to waypoints. It can avoid obstacles using both long- and near-distance stereo vision through navigational cameras on the mast and hazard avoidance cameras on the body, just like NASA's Mars rovers. "If a stone is too big, the rover will automatically turn, then go around it." [15:41]

Offline Lars_J

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Nice!

One Q springs to mind - is the rover able to operate independently, out of visual range from the lander?

Thanks to Emily Lakdawalla and her translation of a press briefing, seems like the rover can operate by itself.

Quote
Wu Weiren also talked about the rover having autonomous navigation capability. The Soviet Lunokhods required television monitors and continuous round-the-clock shifts of drivers to manually tele-operate them. Wu said that Yutu can be operated in this mode, but that there is also a "completely independent operation mode" in which it can be navigated to waypoints. It can avoid obstacles using both long- and near-distance stereo vision through navigational cameras on the mast and hazard avoidance cameras on the body, just like NASA's Mars rovers. "If a stone is too big, the rover will automatically turn, then go around it." [15:41]

My question was not really related to navigation - it is more about communication ability. Can the rover operate independently of the lander on a long trek?

Offline hop

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My question was not really related to navigation - it is more about communication ability. Can the rover operate independently of the lander on a long trek?
The big HGA on the rover mast says yes ;)

Offline plutogno

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plus, IIRC there is a beyond-the-horizon radio link with the lander

Offline OzWill

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My question was not really related to navigation - it is more about communication ability. Can the rover operate independently of the lander on a long trek?

Did some digging, according to this report (sorry, in Chinese), the lander can relay data from Yutu, but both the rover and lander can communicate directly with Earth.

Offline AJA

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plus, IIRC there is a beyond-the-horizon radio link with the lander

The moon has a beyond-the-horizon radio-comm facilitating ionosphere?

Offline MadCow

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Don't know if these have been posted:


Offline plutogno

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to the Chinese speakers: any new info?

Offline MadCow

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Not much new, apart from confirming the distance of each spot they took photos of each other. A - approx. 9 metres from the lander, B/C/D- approx. 10m, E - approx 18m. The big bold text reads: 5 spots, 5 angles.

Read a post from 9ifly, Mr Weiren Wu (chief desinger of Chang'e project) said on CCTV the instruments (or maybe he meant the vehicles) fared better than they expected in term of adapting the extremely high and low temperature. So he expected they should have a longer life span than original expected.

Offline savuporo

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plus, IIRC there is a beyond-the-horizon radio link with the lander

The moon has a beyond-the-horizon radio-comm facilitating ionosphere?

Apparently, the answer is not as obvious as you would think.
http://ntrs.nasa.gov/search.jsp?R=20080046911
Quote
   Long-range, over-the-horizon (transhorizon) radio wave propagation is considered for the case of the Moon. In the event that relay satellites are not available or otherwise unwarranted for use, transhorizon communication provides for a contingency or backup option for non line-of-sight lunar surface exploration scenarios. Two potential low-frequency propagation mechanisms characteristic of the lunar landscape are the lunar regolith and the photoelectron induced plasma exosphere enveloping the Moon



Google for "Path Loss Prediction Model of Radio Propagation over Lunar Surface"

http://link.springer.com/chapter/10.1007/978-3-642-25002-6_77#page-1
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070025224_2007025210.pdf

Anyone want to bet that Chang'e/Yutu have 1Mhz tansceivers ?

EDIT: actually more likely, i would think they will have variable frequency transceivers and they'll run some surface radio propagation experiments across the likely frequency ranges.
« Last Edit: 12/22/2013 08:03 PM by savuporo »
We are sorry to announce that due to irreversible nature of the events depicted in this movie, there will not be a "Gravity 2"

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