Author Topic: Chang'e-4 lunar operations  (Read 212397 times)

Offline Blackstar

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Re: Chang'e-4 lunar operations
« Reply #300 on: 01/29/2019 06:15 pm »
Long March 5 schedule delayed--they were predicting a launch this January, but are now saying July. This seems to me that the Chang'e 5 mission, scheduled for the fourth LM5 flight, could be delayed and not happen in 2019:

http://www.xinhuanet.com/english/2019-01/29/c_137784351.htm

http://www.leonarddavid.com/china-plans-return-to-flight-of-long-march-5-booster/?fbclid=IwAR2B571WV1Fx3ivexYXL3GFzOMXhMnrcWVgdl54tO6zvmDP97Y-nN170IMA

But they seem to be talking about still trying to launch CE5 in 2019, so maybe the slip of the Long March 5 launch from January to July is something they previously planned but did not announce.
« Last Edit: 01/29/2019 09:18 pm by Blackstar »

Offline Olaf

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Offline SciNews

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Re: Chang'e-4 lunar operations
« Reply #302 on: 01/31/2019 09:27 am »
Xinhua: China's Chang'e-4 probe wakes up after first lunar night
http://www.xinhuanet.com/english/2019-01/31/c_137789743.htm
Quote
The lander woke up at 8:39 p.m. Wednesday, and the rover, Yutu-2 (Jade Rabbit-2), awoke at about 8:00 p.m. Tuesday, surviving their first lunar night after making the first-ever soft landing on the far side of the moon, said CNSA.
Xinhua: Chang'e-4 finds moon's far side colder than expected during night
http://www.xinhuanet.com/english/2019-01/31/c_137789823.htm
Quote
China's Chang'e-4 probe, having made the first-ever soft landing on moon's far side, found that the temperature of the lunar surface dropped to as low as minus 190 degrees centigrade, colder than expected.

Offline sophismos

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Re: Chang'e-4 lunar operations
« Reply #303 on: 01/31/2019 03:23 pm »
Xinhua: Chang'e-4 finds moon's far side colder than expected during night
http://www.xinhuanet.com/english/2019-01/31/c_137789823.htm
Quote
China's Chang'e-4 probe, having made the first-ever soft landing on moon's far side, found that the temperature of the lunar surface dropped to as low as minus 190 degrees centigrade, colder than expected.
Oxygen: boiling point is -183 degrees centigrade (−297.332 °F), melting point is -218 degrees centigrade; so at -190°C LH-LOX-Engines might get problems

Offline Olaf

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Offline Olaf

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Offline Phil Stooke

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Re: Chang'e-4 lunar operations
« Reply #306 on: 02/02/2019 11:22 pm »
The shadow shows it is pre-sunset on the previous lunar day, not post-sunrise this lunar morning.  But it may have been transmitted since sunrise.

Online eeergo

Re: Chang'e-4 lunar operations
« Reply #307 on: 02/04/2019 08:28 pm »
Yutu moving and the radio booms in the mothership deploying (should be first lunar day events transmitted now):

https://twitter.com/AJ_FI/status/1092500087148892161
-DaviD-

Offline Phil Stooke

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Re: Chang'e-4 lunar operations
« Reply #308 on: 02/06/2019 06:15 pm »
http://www.9ifly.cn/forum.php?mod=viewthread&tid=5819&extra=&page=89

This link is to the 9ifly forum, where a user has posted a map of Von Karman showing names "approved by the IAU" (the IAU planetary nomenclature site at USGS does not show it  but they may not have updated yet, perhaps due to shutdown issues).

Three craters around the landing site take names from the 'summer triangle' of  bright stars, Vega, Altair, Deneb but using their Chinese names.  The landing site is Statio Tianhe, where Tianhe means Milky Way.  The names refer to the story of the Weaver and the Cowherd, lovers separated by the Milky Way and allowed to meet by crossing on a bridge formed of magpies, the same story from which the relay satellite gets its name.  Finally the central peak is named Mons Tai after Taishan, a mountain in China.

Offline SciNews

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Re: Chang'e-4 lunar operations
« Reply #309 on: 02/06/2019 07:00 pm »

Offline chetan_chpd

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Re: Chang'e-4 lunar operations
« Reply #310 on: 02/07/2019 10:12 am »
its more than a month after chang'e 4 landing...
does it take very long time for LRO to adjust it's orbit in order to be exactly on top of chang'e 4 landing site?

i thought the above link would show "before- after landing" pics.

Online eeergo

Re: Chang'e-4 lunar operations
« Reply #311 on: 02/07/2019 11:58 am »
its more than a month after chang'e 4 landing...
does it take very long time for LRO to adjust it's orbit in order to be exactly on top of chang'e 4 landing site?

i thought the above link would show "before- after landing" pics.

Probably don't wanna adjust it and spend fuel. Chang'e-4 isn't going to move now, and everyone knows exactly where it is, so the value of imagery is limited and won't change with time. If they were able to get this picture by slewing, precession should soon take them close to the site for a more vertical view.

It is improbable there are similar, from-the-side images of the area from before the landing.
-DaviD-

Offline Phil Stooke

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Re: Chang'e-4 lunar operations
« Reply #312 on: 02/08/2019 05:12 am »
LRO doesn't have to adjust its orbit, and will not do so except for very serious reasons to conserve fuel. 

The Moon rotates under an orbiter's orbit plane, so if LRO was 300 km east of the landing site in Von Karman on the 30th when it took that image, on the next orbit it was closer, and on the next orbit closer still.  Approximating here, a point on the surface moves about 12 degrees to the east in a lunar day at the equator, so about 9 degrees or 270 km in a day at this latitude. 

So LRO passed over the lander with a nice vertical view on the 31st as we were told earlier.  It almost certainly took an image, but it has not been released yet.  And we have a very nice pre-landing image of the site, LROC image M134022629L:

http://wms.lroc.asu.edu/lroc/view_lroc/LRO-L-LROC-2-EDR-V1.0/M134022629LE

From that link you can get a zoomable version and download the raw data (very large file). 


Offline mcgyver

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Re: Chang'e-4 lunar operations
« Reply #313 on: 02/08/2019 07:39 am »
NASA: First Look: Chang'e Lunar Landing Site
https://www.nasa.gov/feature/goddard/2019/first-look-change-lunar-landing-site
Couldn't they just wait for a meaningful image before releasing? This image is totally useless.


Offline ugordan

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Re: Chang'e-4 lunar operations
« Reply #314 on: 02/08/2019 07:48 am »
This image is totally useless.

Speak for yourself.

Offline SciNews

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Re: Chang'e-4 lunar operations
« Reply #315 on: 02/09/2019 08:53 am »

Online eeergo

-DaviD-

Offline mcgyver

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Re: Chang'e-4 lunar operations
« Reply #317 on: 02/11/2019 01:39 pm »
Interactive zoomable LROC images:


Pre-landing:

http://lroc.sese.asu.edu/posts/1084 -   NAC M134022629LR (too short ID?)
http://lroc.sese.asu.edu/posts/1087 -   NAC M1298916428LR


Aafter landing:

http://lroc.sese.asu.edu/posts/1090  (Jan 30) - NAC M1303521387LR
http://lroc.sese.asu.edu/posts/1091  (Jan 31) - NAC M1303570617LR





Official landing site coordinates: Latitude -45.457° N, Longitude 177.589° E ( http://lroc.sese.asu.edu/posts/1087 )


First tweet about landing site coords: "Looks like Change-4 landed near 45.47084 South,  177.60563 East "Actual coordinates: 45.45700°S, 177.58900°E  -  MAP
Absurdly similar location: 45.47084 South, 176.60563 EastMAP  (!!!)

Offline whitelancer64

Re: Chang'e-4 lunar operations
« Reply #318 on: 02/11/2019 08:09 pm »
https://twitter.com/AJ_FI/status/1094871037311881216

Nice to hear they have beaten their previous distance record.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline Liss

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Re: Chang'e-4 lunar operations
« Reply #319 on: 02/12/2019 07:35 am »
Officially:

http://www.spacechina.com/n25/n2014789/n2014804/c2486267/content.html
Quote
嫦娥四号着陆器、巡视器在春节期间工作正常 今日进入月夜休眠模式
CE-4 Lander and Patrol are working normally during the Spring Festival. Entering the Moonlight Sleep Mode today.
来源:中国探月工程     
Source: China Lunar Exploration Project
日期:2019年02月11日   
Date: February 11, 2019

春节期间,嫦娥四号着陆器和巡视器工作稳定,能量平衡,各系统工况正常,数据传收正常,红外成像光谱仪、中性原子探测仪等科学载荷顺利开展科学探测活动。巡视器于2月11日2时22分移动至LEO0210点,在月面累计行驶120米左右。
During the Spring Festival, the CE-4 lander and rover were stable, the energy was balanced, the working conditions of each system were normal, the data transmission was normal, and the scientific load such as infrared imaging spectrometer and neutral atomic detector successfully carried out scientific exploration activities. The rover moved to [LEO0210 point] on [February 11] [02:22] and accumulates around 120 meters on the lunar surface.
经地面分析,目前着陆器、巡视器状态满足月夜休眠要求,将按计划于2月11日19时与19时30分先后进入月夜休眠模式。巡视器预计将于2月28日唤醒,着陆器预计将于3月1日唤醒,继续开展科学探测活动。
After ground analysis, the current state of the lander and rover meets the requirements for moon-night dormancy, and will enter the moon-night sleep mode at 19:00 and 19:30 on February 11 as planned. The rover is expected to wake up on February 28, and the lander is expected to awaken on March 1 to continue scientific exploration activities.
« Last Edit: 02/12/2019 07:36 am by Liss »
This message reflects my personal opinion based on open sources of information.

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