Author Topic: China just landed a probe on the far side of the moon!  (Read 8332 times)

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Offline coppercone2

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Re: China just landed a probe on the far side of the moon!
« Reply #25 on: January 06, 2019, 10:12:29 am »
does anyone think it would be cute and amusing if there was a russian, japanese and american ones near the same location so you can't take a picture of one without seeing the other ones, like a crowded moon scenario?
 

Offline soldar

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Re: China just landed a probe on the far side of the moon!
« Reply #26 on: January 06, 2019, 11:00:36 am »
It is a huge accomplishment.

Unfortunately, at least in many other areas, they are anything but "open".
 
They are a totalitarian state which is by definition secretive.

They have always been that way. Even before the PRC.

They have never had anything even remotely resembling democracy in mainland China.

Its a complicated situation.
It's a complicated situation. I had prepared a long reply to your post but then I saw this
Can you please leave the politics off the forum.
and I thought it is better to err on the side of caution. If being married has taught me anything it is that it is always better to err on the side of caution. :)
All my posts are made with 100% recycled electrons and bare traces of grey matter.
 

Offline rdl

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Re: China just landed a probe on the far side of the moon!
« Reply #27 on: January 06, 2019, 12:19:14 pm »
I think the real trick was putting their relay satellite (Queqiao) at the Earth-Moon L2 point. I'm not sure anyone else has ever done that.

Yes. China is usually not shy to put these things on media if it knows the success rate is near 100%, such as launching a manned mission with all proven technology. After all, no one has ever landed on the back of the moon.

Technically, landing on the far side of the moon shouldn't be any more difficult than then ear side, right?
The far side would have a signal trip delay time, as it has to go through the repeater at the legrange point, but the descent would be automated in either case.
 

Offline EEVblog

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Re: China just landed a probe on the far side of the moon!
« Reply #28 on: January 06, 2019, 01:29:26 pm »
I think the real trick was putting their relay satellite (Queqiao) at the Earth-Moon L2 point. I'm not sure anyone else has ever done that.

There are two others it seems:

https://en.wikipedia.org/wiki/List_of_objects_at_Lagrangian_points#L2_2

L2 is unstable and needs to be corrected every 23 days:
https://wmap.gsfc.nasa.gov/mission/observatory_l2.html
 

Offline cdev

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Re: China just landed a probe on the far side of the moon!
« Reply #29 on: January 06, 2019, 01:31:17 pm »
The wheel design on the rover is an interesting one. These designs keep improving and borrowing from one another so even though we have independent efforts to explore the Moon, Mars and other planets there still is a total effect that is much more than the sum of it's parts.

The idea of a radio observatory on the dark side of the Moon where the Earth's radio signals and even it's light are not present, is really interesting to me. 

Maybe one of the most interesting things that I think we could achieve short term in space.

It would be smart for all the Earth's countries to pool their efforts to build a really powerful one. It would be an opportunity for people to propose things to best utilize the platform. Cubesats have been pretty successful at getting schools and other organizations all around the world involved in space. A shared Moon observatory could take that a step farther.

Stanley Kubrick's incredible "2001: A Space Odyssey" of course is the film that does the best job of depicting a human presence on the Moon in the future.

Showing us all how science fictions films should be done, he really did his homework on what that future might look like putting that film really in a class by itself as far as its special effects - something that right there I think did a lot for our planet's collective science literacy.

I cant think of another science fiction film that has done anywhere near as well. Can anybody here think of one? Its especially impressive given the embryonic state of computer graphics at the time.

Still, he did a really good job of guessing what would be happening in his future world, using the very best resources and advice available to him at that time. He was a real master of the art.

It contains its great scenes of the huge space station which in the movie appears to be a shared international project, although the bases on the Moon seem to be built by nations.

Clearly, Kubrick also put a lot of thought into the subtleties of politics in space in the future world he created. Really, its a masterpiece in every possible way. It still takes my breath away to see it. I've watched it dozens of times.


-----

Also, when I've found stuff on the Chinese space missions, like their live spacewalk a few years ago, I have to admit I was literally crying with joy. I would really like to see much more cooperation between the world's countries in space.

China's use of the Soyuz capsule makes sense as it has a good safety record and it also means their SVs should be compatible/interoperable with the ISS.







 
« Last Edit: January 06, 2019, 01:58:18 pm by cdev »
"What the large print giveth, the small print taketh away."
 

Offline EEVblog

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Re: China just landed a probe on the far side of the moon!
« Reply #30 on: January 06, 2019, 01:38:25 pm »
The idea of a radio observatory on the dark side of the Moon where the Earth's radio signals and even it's light are not present, is really interesting to me. 

Some amazing science can be done on the far side of the moon, and I think this could/should be a real compelling reason to have an initial permanent scientific colony on the moon.

Quote
Maybe one of the most interesting things that I think we could achieve short term in space.

Trivial to do compared to the relative pipe dream of a colony on Mars.

Quote
The movie "2001: A Space Odyssey" of course is the film that does the best job of depicting a human presence on the Moon in the future.

I cannot wait for the Artemis movie to come out, this will be spectacular!
 
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Offline coppercone2

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Re: China just landed a probe on the far side of the moon!
« Reply #31 on: January 06, 2019, 06:31:42 pm »
clearly you have not seen the adventures of pluto nash if you think the two thousand and one depiction of the moon is at all accurate.
 

Offline apis

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Re: China just landed a probe on the far side of the moon!
« Reply #32 on: January 06, 2019, 10:06:38 pm »
It would be cool if the first moon base was an international project, but as things are developing it looks like it will most likely be Chinese. I hope they will let the rest of us come and visit. ^-^

 

Offline VK3DRB

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Re: China just landed a probe on the far side of the moon!
« Reply #33 on: January 07, 2019, 12:23:02 pm »
Chang'e is a Chinese goddess. It seems a great irony these mission names are based on religious hocus pocus. Maybe the Chinese government copied NASA's moronic naming convention for its missions (Apollo, Mercury, Juno, Saturn, Thor). The names have nothing to do with common sense or science.

But the fact the Chinese got a probe in the far side and can relay data back to earth is a remarkable feat in anyone's language. For Apollo 8, there was a known roughly 50% chance it would end in disaster, and yet it the American media/govt televised it up front. The Chinese government said next to nothing in case Chang'e 3 failed. Therein lies one big difference between relative freedom in a democracy and thought control by a totalitarian state. So in one way the Chinese proletariat only got to enjoy part of the achievement.
 

Offline coppercone2

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Re: China just landed a probe on the far side of the moon!
« Reply #34 on: January 07, 2019, 12:26:03 pm »
would you rather see it named after communist officials... i think they did a bang on job on the name
 

Offline schmitt trigger

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Re: China just landed a probe on the far side of the moon!
« Reply #35 on: January 07, 2019, 06:42:06 pm »

What will they find? 2001 Space Odyssey's Monolith?
 :-DD

Now seriously....radio telescope observation conditions, free from terrestrial noise, should be excellent.
« Last Edit: January 07, 2019, 06:44:34 pm by schmitt trigger »
 

Offline cdev

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Re: China just landed a probe on the far side of the moon!
« Reply #36 on: January 07, 2019, 06:44:18 pm »
Despite the issues which have been discussed, I think its a very positive thing that they did this, I like the name and the mythical story behind it and think it makes sense, as it makes sense to all the Chinese Ive asked about it, and thats what counts as it is their accomplishment which they have every right to be very very proud of.

Its a very real accomplishment that speaks to how far they have come in a very short time.
as well as to all human progress and our shared potential.

So a toast! To the many scientists and workpeople who made it possible, to the Moon goddess Chang'e and her faithful white rabbit companion, and to many more successes in space for all the nations of the Earth and our human race.
« Last Edit: January 07, 2019, 06:47:15 pm by cdev »
"What the large print giveth, the small print taketh away."
 

Offline Rick Law

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Re: China just landed a probe on the far side of the moon!
« Reply #37 on: January 07, 2019, 07:45:19 pm »
Yes. China is usually not shy to put these things on media if it knows the success rate is near 100%, such as launching a manned mission with all proven technology. After all, no one has ever landed on the back of the moon.

Technically, landing on the far side of the moon shouldn't be any more difficult than then ear side, right?
The far side would have a signal trip delay time, as it has to go through the repeater at the legrange point, but the descent would be automated in either case.

Not for the landing itself, but to find out how things went, they needed communication/relay satellite(s) since it happened on the dark side.

I think at least one of the relay satellite didn't work - the one build by HIT (Harbin(?) Institute of Technology) students.  But I couldn't find that article again to confirm...

Interesting things going on:

Chang’e 4 - That was the one that just landed - launcher was Long March 3B carrier rocket
Chang’e 5 - first sample-return (2kg lunar soil) mission with a moon rover and robotic arm to do the collection.  Planned launcher is/was Long March 5, but original date delayed due to the failure of the Long March 5 launcher.  Probably looking at some time in 2019 still.
Chang’e 6 - second sample-return mission, target launch 2020 also on Long March 5 if Chang’e 5 went according to plan.
 

Offline chris_leyson

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Re: China just landed a probe on the far side of the moon!
« Reply #38 on: January 07, 2019, 10:54:56 pm »
This is the first serious attempt at low frequency radio astronomy outside of the ionosphere so we really don't know what we might hear. Karl Jansky at Bell Labs started it all off in 1931 whilst investigating sources of radio interference or static. He eventually categorized them into three types of static: nearby thunderstorms, distant thunderstorms, and a faint steady hiss of unknown origin. He spent over a year investigating the source of the third type of static and determined that the signal repeated on a cycle of 23 hours and 56 minutes, a sidereal day.
By comparing his observations with optical astronomical maps, Jansky concluded that the radiation was coming from the Milky Way and was strongest in the direction of the center of the galaxy. He published "Electrical disturbances apparently of extraterrestrial origin" in 1933, the astronomers didn't show much interest and Bell Labs wouldn't let him build a larger antenna, so that was it. He does however have a unit of spectral flux density named after him, 1Jy = 10-26W/(m2.Hz). So that's how radio astronomy got started, so when any science gets published the results will probably be in Janskys, they usually are.

Radboud University Radio Lab and ASTRON might be two useful sources when anything is published.

https://www.ru.nl/astrophysics/research/radboud-radio-lab-0/
https://www.astron.nl/r-d-laboratory/ncle/netherlands-china-low-frequency-explorer-ncle

BTW. Jansky's radio observations were done at 20.5MHz, so that's why went rabbiting on about Karl Jansky.

EDIT: According to the Earth Observation Portal website
"Two Chinese microsatellites, DSLWP -A and -B (Discovering the Sky at Longest Wavelengths Pathfinder), also referred to as Longjiang-1 and Longjiang-2, were launched with the Chang’e 4 relay mission to conduct astronomical observations from deep space (Selenocentric, elliptical orbit). The two microsatellites were developed by the Harbin Institute of Technology. Each microsatellite has a mass of 47 kg"
Longjiang-1 failed but Longjiang-2 reached orbit.

Also, according to the mission status on the eoportal website, "the three 5-meter antennas of the low-frequency radio spectrometer on the lander have fully spread out". Dated 5th January

https://directory.eoportal.org/web/eoportal/satellite-missions/c-missions/chang-e-4
« Last Edit: January 07, 2019, 11:21:56 pm by chris_leyson »
 
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Offline raptor1956

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Re: China just landed a probe on the far side of the moon!
« Reply #39 on: January 08, 2019, 01:24:20 am »
Those first sets of photos are very cool and I hope more are forthcoming.  The rover doesn't look to have much range and I doubt we'll see it venture more than a km from the landing spot, but, I hope I'm wrong and that things puts on some decent mileage. 

Is there a breakdown of the cameras and other scientific equipment on the rover and lander -- it would be nice to know what the potential is?


Brian
 

Offline raptor1956

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Re: China just landed a probe on the far side of the moon!
« Reply #40 on: January 11, 2019, 09:20:35 pm »
Well Scott Manley just linked a video of the landing -- very nice...



It would be nice to see some data overlay for vertical and horizontal velocity, radar altitude, fuel quantity, thrust setting, etc, but the video is pretty decent.


Brian
 
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Offline BrianHG

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Re: China just landed a probe on the far side of the moon!
« Reply #41 on: January 11, 2019, 09:39:53 pm »
Industrializing the moon:
https://youtu.be/bGcvv3683Os
 

Offline Electro Detective

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Re: China just landed a probe on the far side of the moon!
« Reply #42 on: January 11, 2019, 11:17:56 pm »

It looks a bit suss... 

OneHungLow backers planning to build factories up there to employ very cheaper 6 armed alien child labour?  >:D

Good news for us > Aneng multimeters "Made In Moon"  :-DMM 

cheaper by the dozen...   :clap:

 

Offline Mr. Scram

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Re: China just landed a probe on the far side of the moon!
« Reply #43 on: January 11, 2019, 11:21:31 pm »

It looks a bit suss... 

OneHungLow backers planning to build factories up there to employ very cheaper 6 armed alien child labour?  >:D

Good news for us > Aneng multimeters "Made In Moon"  :-DMM 

cheaper by the dozen...   :clap:
What looks "suss"?
 

Offline apis

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Re: China just landed a probe on the far side of the moon!
« Reply #44 on: January 11, 2019, 11:23:50 pm »
I have no idea if you can make a bomb out of only 3He. But they would have to mine it first. And I believe all space nations, like China, already have fusion bombs so it wouldn't really change anything. I hope China builds a moon base though, and that it makes the US so paranoid that they also want one. It might just be enough to start another space race. :)

cheaper by the dozen...   :clap:
You are going to be very disappointed if you think that is how it works.
« Last Edit: January 11, 2019, 11:26:55 pm by apis »
 

Offline coppercone2

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Re: China just landed a probe on the far side of the moon!
« Reply #45 on: January 11, 2019, 11:37:39 pm »
how do you trigger the fusion reaction with a fission reaction?

don't you still need insane pressures?
 

Offline apis

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Re: China just landed a probe on the far side of the moon!
« Reply #46 on: January 11, 2019, 11:47:51 pm »
The firs tone is mutual destruction and can only be used as a token force. The second is no more than an over powered conventional bomb.
But an opponent with nuclear weapons would still respond with fission-fusion bombs if they believed they were under attack, so you would end up with mutual destruction either way.
 

Offline coppercone2

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Re: China just landed a probe on the far side of the moon!
« Reply #47 on: January 11, 2019, 11:55:05 pm »
if you can make a pure fusion bomb (how?) won't it be very clean apart from neutron radiation causing some isotopes? Does it even make neutrons?

That decreases the whole 'radioactive zombie mutant cancer" problem that makes nuclear weapons distasteful and makes it more like a high explosive weapon.

Even if it made some neutron radiation, it should be safe to use in the atmosphere as a air defense weapon or ground shock weapon.

But how do you trigger a fusion reaction without a nuclear energy source? do you surround it by a grid of fusion reactors that are laser pumped or something?
« Last Edit: January 11, 2019, 11:58:27 pm by coppercone2 »
 

Offline apis

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Re: China just landed a probe on the far side of the moon!
« Reply #48 on: January 12, 2019, 12:06:53 am »
It's not only the radiation. They are not exactly precision weapons, they can wipe out entire cities which are inevitably full of civilians. So called weapons of mass destruction. Similar weapons that kill indiscriminately are also banned. Like chemical and biological weapons.

If they have both small yield and are very clean it might be considered a normal bomb, but in that case, you could also use a normal bomb for that, no?
 

Offline coppercone2

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Re: China just landed a probe on the far side of the moon!
« Reply #49 on: January 12, 2019, 12:09:51 am »
But an opponent with nuclear weapons would still respond with fission-fusion bombs if they believed they were under attack, so you would end up with mutual destruction either way.

Since it doesn't need a fission trigger, much lower yield can be achieved.
If a nuke has only yield of a few tens to a few hundreds tons, it will be a hard decision to retaliate back with real nukes.

how does it work without a fission trigger? Where do you get the activation energy from?
 


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