Author Topic: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018  (Read 19690 times)

Offline Phil Stooke

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #60 on: 03/05/2017 02:17 PM »
It's correct, of course, to say that the date of that conference abstract is very recent , but it is really about CE-5, and it's most likely that the authors dropped in a date for CE-4 on the spur of the moment without checking it was still current.  2018 seems well established now. 

My main interest right now is learning about an exact landing target.  It's supposed to be the South Pole-Aitken basin, but that's a big place.  There are suggestions of a site at roughly 44 south near the Apollo basin.  Note that CE-3, the new CE-5 sites from the aforementioned abstract and this area for CE-4 are all at pretty much the same latitude (absolute values! - north or south).  The thermal controls seem to be optimized for that latitude.

Offline plutogno

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #61 on: 03/24/2017 08:30 PM »
An Overview of the Mission and Technical Characteristics of Change’4 Lunar Probe

Quote
Change’4 Lunar Probe will softly land on the farside of the Moon for the first time of all mankind and carry out in-situ and rovering exploration. In this paper, the scientific significance and engineering difficulties of Change’4 are introduced and the probe’s general design, including the aspects of landing site selection, relay communication, trajectory design of relay satellite is explained. Besides, four key technologies namely, safe landing strategy on complex terrain, orbit design and control of libration point 2, relay communication on L2, RTG and electric-thermal utilization as well as how to realize them are also discussed. Finally the prospect of the prominent technological breakthrough of Change’4 is described.

http://engine.scichina.com/publisher/scp/journal/SCTS/doi/10.1007/s11431-016-9034-6?slug=abstract

Offline Steven Pietrobon

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #62 on: 03/26/2017 04:58 AM »
Some highlights from the paper.

Chang'e 4 launching in 2018.

The relay satellite will launch six months before the lander.

The relay satellite will perform a Lunar swing-by to reach EML2. A burn of 200 to 300 m/s will be performed at perilune. Initial transfer orbit is 200x380,000 km.

The lander will carry a rover.

The lander is powered by solar panels during the day and an RTG during the night. Chang'e 3 also used an RTG.

Landing is targeted for the South-Pole Aitken Basin.

Earth-Relay communications is in S-Band. Relay-Lander/Rover communications is in X-Band. Lander-Rover communications is in UHF. The relay satellite can communicate simultaneously with the lander and rover.

The lander will carry a low-frequency radio spectrometer (LFS). Not exactly clear on the band, but the conclusion indicates from 0.1 to 10 MHz.
« Last Edit: 03/26/2017 04:59 AM by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline plutogno

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Offline Dalhousie

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #64 on: 04/11/2017 11:21 PM »
The lander is powered by solar panels during the day and an RTG during the night. Chang'e 3 also used an RTG.


RTG or RHU?
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline Steven Pietrobon

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #65 on: 04/12/2017 05:06 AM »
The lander is powered by solar panels during the day and an RTG during the night. Chang'e 3 also used an RTG.


RTG or RHU?

The article says RTG.

"4.4 Power Supply with Radioisotope Thermoelectric Generator (RTG) and Thermoelectric Technology Application

For data collection of the temperature of the lunar soil in moon night, the temperature sensor has to have power supply. Currently, the most realistic method is to utilize the RTG, which is based on Seebeck principle to transform the heat energy into the electric energy. When generating electric power, the RTG can also supply great heat energy to regulate temperature. Generally Pu-238 is used as the RTG source [10].

Compared with the RTG used in Change’3, the thermoelectric module should be increased in the RTG of Change’4, which may mean various technical difficulties, including high-performance thermoelectric material manufacture, high-performance thermoelectric components design and assembly, high-efficiency heat transformation, etc."
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Dalhousie

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #66 on: 04/12/2017 08:50 AM »
The lander is powered by solar panels during the day and an RTG during the night. Chang'e 3 also used an RTG.


RTG or RHU?

The article says RTG.

"4.4 Power Supply with Radioisotope Thermoelectric Generator (RTG) and Thermoelectric Technology Application

For data collection of the temperature of the lunar soil in moon night, the temperature sensor has to have power supply. Currently, the most realistic method is to utilize the RTG, which is based on Seebeck principle to transform the heat energy into the electric energy. When generating electric power, the RTG can also supply great heat energy to regulate temperature. Generally Pu-238 is used as the RTG source [10].

Compared with the RTG used in Change’3, the thermoelectric module should be increased in the RTG of Change’4, which may mean various technical difficulties, including high-performance thermoelectric material manufacture, high-performance thermoelectric components design and assembly, high-efficiency heat transformation, etc."

Thanks
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline savuporo

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #67 on: 04/13/2017 02:13 AM »
As a backgrounder on the RTG  : http://www.thespacereview.com/article/2401/1
Also do note comments regarding VNIIEF
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Offline wahaha

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #68 on: 06/06/2017 12:04 PM »
Landing point 45.5S, 178E

May 2018, relay sat launched
Dec 2018, lander and rover launched.

« Last Edit: 06/06/2017 12:14 PM by wahaha »

Offline Phil Stooke

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #69 on: 06/06/2017 04:08 PM »

"Landing point 45.5S, 178E"

Very interesting.  This is on the flat floor of the large crater Von Karman, with a bit of ejecta from the relatively young crater Finsen.  Until now most indications had been for a landing near the Apollo basin at about 42 south, 157 west (203 east).

Offline Steven Pietrobon

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #70 on: 06/09/2017 10:42 AM »
Here's an image of Von Karmen crater.
« Last Edit: 06/09/2017 10:44 AM by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Phil Stooke

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #71 on: 06/11/2017 08:27 PM »
Maps detailing the landing area.


Offline plutogno

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #72 on: 06/14/2017 05:58 AM »
China to establish simple ecosystem on Moon using plants, insects

http://en.people.cn/n3/2017/0613/c90000-9227854.html

Offline savuporo

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #73 on: 06/16/2017 11:56 PM »
More Chinese space seeds

http://parabolicarc.com/2017/06/16/paging-mark-watney-china-send-potato-seeds-moon/

Except this time it can't be chalked up to Chinese belief of 'magic space seeds'. It's an actual biosphere experiment
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Offline Dalhousie

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #74 on: 06/18/2017 07:29 AM »
More Chinese space seeds

http://parabolicarc.com/2017/06/16/paging-mark-watney-china-send-potato-seeds-moon/

Except this time it can't be chalked up to Chinese belief of 'magic space seeds'. It's an actual biosphere experiment

No magic seeds. Everyone has researched the effect of spaceflight on seeds, not just China.
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline plutogno

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Re: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - Late 2018
« Reply #75 on: 06/25/2017 08:07 AM »
the latest issue (2-2017) of the Chinese Journal of Deep Space Exploration has quite a few papers (all in Chinese, alas) on CE-4, lunar farside landing, Lunar L1 orbits etc.

http://jdse.bit.edu.cn/sktcxben/ch/index.aspx?year_id=2017&quarter_id=2
« Last Edit: 06/25/2017 08:16 AM by plutogno »

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