Author Topic: LIVE: Chang'e-3 lunar probe and rover Lunar Landing December 14, 2013  (Read 231791 times)

Offline jumpjack

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Damn, the landing footage watched while listening Strauss's Danubio Blu is just amazing! :-)
Is anybody able to upload a short version of the video which includes this song? You've just to make moment 04:30 of the song match with the touch down and you're done! :-)
« Last Edit: 12/17/2013 05:24 PM by jumpjack »
-- Jumpjack --

Offline Nick

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To get back to Chang'e, I'm not that surprised the moon turned out brown. Every time I worked with spacecraft color imagery of the Moon, if I white-balanced it to the solar spectrum in vacuum, I got a similar brown color, whereas things like ice would turn out white. Same for Mercury.

I don't understand what's going on there. I have always read that, in bulk, the Moon is a very dark grey - similar to a tarmac road surface. More technically, I am sure that I have read that the Moon's spectral curve is extremely similar to the Sun's - which is, of course, saying the same thing, and which wouldn't be possible if it had a bulk brown colour. (So much so, that I think Hubble has imaged the Moon as a calibration target for other planetary bodies, because it can't image the Sun. Somebody here probably knows that, one way or the other...)

That's not to say that individual areas of the Moon don't differ slightly from grey - I have seen highly Photoshopped amateur images that bring out colour differences ranging from blue to brown. but those were highly processed with the specific intention of bringing out slight colour differences.

On a personal, anecdotal, level, a few years ago I photographed the Taj Mahal by the light of a full Moon. When I got back home and loaded the images up into Lightroom, I found that simply "overexposing" the images produced an excellent rendering of the scene as it appeared the following day in daylight... (Camera on daylight balance in both cases.) I wished I hadn't done it, because it rather shattered the magic of the scene...  :(

Nick

Offline Phil Stooke

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Look up at the full moon tonight - is it brown? 

Color is too complicated to trust any rendition of it.  I just set image mode to Grayscale when I want it to look right.

Offline woods170

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http://v.youku.com/v_show/id_XNjQ4OTUzMjY0.html

From 9ifly
http://bbs.9ifly.cn/thread-12967-1-1.html

Sorry, newbie here, don't know how to post a vid.  :-[

No problem. The links are fine. And welcome to the forum. :)

Offline AJA

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Here's one example of what the Moon looked like to the Deep Impact spacecraft while transiting Earth's disc: http://farm7.staticflickr.com/6143/5927214387_6f0e61e39f_o.gif

Wow.. you can really make out the highlands on the far side of the moon. There's a bright part in the centre of the lunar disc (when it's near/past the terminator on the Earth) interrupting what should've been a smooth continuation of the lunar terminator..

Split the gif into individual frames (I used ezgif.com/split) to illustrate that..
« Last Edit: 12/17/2013 07:27 PM by AJA »

Online ugordan

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Wow.. you can really make out the highlands on the far side of the moon.

Don't read anything into that, those are ringing artifacts due to the deconvolution process. The high resolution imager on the spacecraft had a design flaw similar to Hubble's mirror that caused all the images to be very blurred. This sequence had processing applied to at least partially recover from the blurring, the ringing is the side-effect.

Quote
Split the gif into individual frames (I used ezgif.com/split) to illustrate that..

Don't need to split it, I made that particular gif...

Offline pagheca

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I have a question. I tried to find the answer in the zillions of post about Chang'e 3 landing but got lost. Sorry if I am, as I'm quite sure, repeating someone else comment...

The lander was expected to shut down the engine 4 meters about the ground and then to the ground (see for example this page).

But the movie seems to show the lander touching down and leaving the engine ON for about 10 more long seconds. What happened?
« Last Edit: 12/17/2013 10:43 PM by pagheca »

Offline MadCow

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A symposium between some press and scientists involved in Chang'e 3 was held today (17th Dec) between 6.00am and 8.00am (UTC) in Beijing. Here're some of the dialogues: (sorry for my poor translation, I'm not very familiar with the aerospace jargons  :( )

He ZHANG (Deputy chief designer of Chang'e 3, mainly responsible for the landing system): Chang'e 3 is working well, everything is functioning well, moon-besed EUV imaging started working.

Press: Has Yutu avoided the crater ahead?

He ZHANG: After seeing that crater, we felt very lucky as well as successful. Apart from the crater, there are some stones around as well. However the landing spot is very flat. It means our system worked well. The crater is bout 10m away, Yutu should be able to avoid it.

Yan SU (National Astronomical Observatories, Chinese Academy of Sciences): 6 of 8 instruments have been functioning. They are Descent Camera, MastCam, Lunar-based Ultraviolet Telescope (LUT), Ground Penetration Radar (GPM), PanCam, Extreme Ultraviolet Imager (EUV).

Press: When can we explore the Mars?

Weiren WU (Chief designer of Lunar project): We're capable of exploring the Mars already. However, when we're going to do it will be decided by the state.

Yan SU (Ground application system, National Astronomical Observatories): We will release sharing data at the earliest possible time.We have been cooperating with ESA, however it's difficult to cooperate with NASA because of its policy.

Weiren WU: The data will be classified as 4 levels. U.S. Congress forbids NASA cooperating with CNSA. NASA had asked Chang'e's trajectory data before the launch, however they refused to provide the trajectory data of their own orbiters.

Press: Aprat from ESA and NASA, do we cooperate with Russia, India, Japan and South American countries?

Weiren WU: We work with ESA, but not NASA. We also have some cooperation with Russia. To work with others, we always need to improve ourselves.

Press: What if Chang'e 3 failed?

Weiren WU: We tried our best, but we also prepared the worst. We had more than 200 troubleshooting plans. But in the end, none of them was used. We would be under immense pressure if it failed, however we believed Chinese people would understand.

He ZHANG: Both USA and former USSR had some failures. However we have the benefit of much improved technology. We used laser rangefinder, 3D laser imaging sensor. They didn't have them in 1960s and 1970s. The main feature of the landing is autonomous obstacle avoidance. There was a carter, 20m diameter, 2 or 3 metres deep. Chang'e 3 successfully avoided it. Chang'e 3 could take three 3D photos, however it wasn't too difficult, so it took only one 3D photo. The computer quickly identified the safe spot, Chang'e 3 panned a little, then landed.

Press: Chang'e 5 will be launched in 2017, will it take another rocket to bring the sample back?

He ZHANG: The rocket will be almost as twice powerful as Chang'e 3's (1000t vs 600t). Yes, there will be another "little rocket" to bring the sample back, although we don't called it as such. It's very difficult new technology. It's still under development.

Press: What are the further tasks for the lander?

He ZHANG: There's a moon-dust integrated load measuring instrument on the lander which will collect moon-dust for a year, so we can analyse the data coming from the lander. To work for a year, the lander has a RHU radioisotope thermoelectric heating system which can keep the temperature in the cabin to minus 30-40 degree during the night.

Press: Chang'e 3 has been such a success, what's the point to fly Chang'e 4?

Weiren WU: We will certainly make some alterations for Chang'e 4 to suit the purposes. We will need more discussion about it.

Press: Any major technical differences between Chang'e 5 and Chang'e 3?

Weiren WU: Lunar orbit rendezvous and docking, sample taking and drilling, sample packing and preservation, returning to the Earth.

Source:
http://210.14.113.38:9080/asop/login.asop?titleId=375

Online Blackstar

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But the movie seems to show the lander touching down and leaving the engine ON for about 10 more long seconds. What happened?

There was speculation earlier in the thread that although the engine was off, there was still some remaining gas escaping.

Online malu5531

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A symposium between some press and scientists involved in Chang'e 3 was held today (17th Dec) between 6.00am and 8.00am (UTC) in Beijing. Here're some of the dialogues: (sorry for my poor translation, I'm not very familiar with the aerospace jargons  :( )

I think it was a great translation! Thanks a lot, some nice information in there! :)

Overall they seem very humble and I hope for some NASA/CNSA cooperation in the future, as scientists on both sides seem to just want to work together. :)

Press: Any major technical differences between Chang'e 5 and Chang'e 3?

Weiren WU: Lunar orbit rendezvous and docking, sample taking and drilling, sample packing and preservation, returning to the Earth.

Drilling on Chang'e 5, awesome! :)
« Last Edit: 12/18/2013 12:56 AM by malu5531 »

Offline lcs

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Images of the Moon taken from ISS also often show such a pale brown color, although I don't know the specific camera white balance settings used. I can't speak for Apollo Hasselblad photography other than it looks spectacular.

Also both Neil Armstrong and the Apollo 12 crew reported the moon looked brown from certain angles and heights early in the lunar morning (for Apollo 12, on the second EVA).  Neil said that when he held the lunar soil in his hand up close, it look gray.   This was in an interview with Patrick Moore shortly after Apollo 12.  The Apollo 10 crew reported brown many times from orbit at low sun levels.

Offline savuporo

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A symposium between some press and scientists involved in Chang'e 3 was held today (17th Dec) between 6.00am and 8.00am (UTC) in Beijing. Here're some of the dialogues: (sorry for my poor translation, I'm not very familiar with the aerospace jargons  :( )

I think it was a great translation! Thanks a lot, some nice information in there! :)

Seconded, thank you very much. !

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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Test of the reentry vehicle for CE-5.

Offline akula2

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Weiren WU: We tried our best, but we also prepared the worst. We had more than 200 troubleshooting plans. But in the end, none of them was used. We would be under immense pressure if it failed, however we believed Chinese people would understand.
Thanks for sharing that interview. I liked this part very much, so good luck to Chinese team  :)

Offline Steven Pietrobon

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http://v.youku.com/v_show/id_XNjQ4OTUzMjY0.html

From 9ifly
http://bbs.9ifly.cn/thread-12967-1-1.html

Thanks for posting that video. Some screen captures. The first showing a descent camera image with a drawing of Chang'e 3 and Yutu imposed on it, the second showing Chang'e 3 marked with a red cross I've added (that's a fairly big crater that it landed next to) and the last showing Chang'e 3 relative to Luna 17 which carried Lunokhod 1.
« Last Edit: 12/18/2013 04:01 AM by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

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