Author Topic: Chang'e-4 lunar probe and rover - CZ-3B- XSLC - December 7, 2018 (18:23 UTC) (Read 119293 times)

Phil Stooke · « **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.

plutogno · « **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

Steven Pietrobon · « **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.

plutogno · « **Reply #63 on:** 04/11/2017 04:36 pm »

Swedish Institute of Space Physics goes back to the Moon
http://www.irf.se/Topical/Press/?dbfile=Swedish%20Institute%20of%20Space%20Physics%20goes%20back%20to%20the%20Moon&dbsec=P3

Dalhousie · « **Reply #64 on:** 04/11/2017 11:21 pm »

Quote from: Steven Pietrobon on 03/26/2017 04:58 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?

Steven Pietrobon · « **Reply #65 on:** 04/12/2017 05:06 am »

Quote from: Dalhousie on 04/11/2017 11:21 pm

Quote from: Steven Pietrobon on 03/26/2017 04:58 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."

Dalhousie · « **Reply #66 on:** 04/12/2017 08:50 am »

Quote from: Steven Pietrobon on 04/12/2017 05:06 am

Quote from: Dalhousie on 04/11/2017 11:21 pm
Quote from: Steven Pietrobon on 03/26/2017 04:58 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

savuporo · « **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

wahaha · « **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.

Phil Stooke · « **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).

Steven Pietrobon · « **Reply #70 on:** 06/09/2017 10:42 am »

Here's an image of Von Karmen crater.

Phil Stooke · « **Reply #71 on:** 06/11/2017 08:27 pm »

Maps detailing the landing area.

plutogno · « **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

savuporo · « **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

Dalhousie · « **Reply #74 on:** 06/18/2017 07:29 am »

Quote from: savuporo 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

No magic seeds. Everyone has researched the effect of spaceflight on seeds, not just China.

plutogno · « **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

Star One · « **Reply #76 on:** 10/10/2017 07:28 pm »

Quote

Jeff Foust @jeff_foust
Long Xiao: planning to launch relay satellite for Chang’e-4 in June 2018, lander in December to farside. #leag2017

https://mobile.twitter.com/jeff_foust/status/917782981519052801

Phillip Clark · « **Reply #77 on:** 01/05/2018 10:28 pm »

Just posting some links for recent information. There is now a separate thread for the Chang'E 4 communications satellite which is due for launch in June 2018:
http://forum.nasaspaceflight.com/index.php?topic=39342.0
It will be the first flight of a CZ-4 class vehicle from Xichang.

This is the China Spaceflight page which covers both Chang'E 4 itself and the communications satellite:
https://www.chinaspaceflight.com/satellite/Deepspace/CE-4/CE-4.html

Finally, this overview was recently posted to the thread for the communications satellite, but it seems to be more "at home" here:
https://www.universetoday.com/138197/upcoming-chinese-lander-will-carry-insects-plants-surface-moon/

Crossed fingers that all will do well for these flights!

Phil Stooke · « **Reply #78 on:** 01/06/2018 06:07 am »

"This is the China Spaceflight page...."

They are not updating at the moment. Not just for CE4, the whole site. Nothing since Nov. 10th. Their Twitter continued until Dec. 21st but has been quiet since. Anyone know what's up, or if there is a good alternative?

Galactic Penguin SST · « **Reply #79 on:** 01/24/2018 10:23 am »

A Chinese news report that confirms that the launch is sticking to December 2018: http://cnews.chinadaily.com.cn/2018-01/08/content_35456298.htm