Chang'e-4 farside landing mission Options

[Phil Stooke]

I'm hearing 24.5 m during the 16th lunar day, 424.5 m total.

Phil

[Phil Stooke]

Here's an abstract for a poster at the next COSPAR meeting:

---------------------
43rd COSPAR Scientific Assembly 2020

Space Studies of the Earth-Moon System, Planets, and Small Bodies of the Solar System (
Human and Robotic Exploration of Moon, Mars, and Asteroids (B0.2)
Consider as poster only.

LOW FREQUENCY RADIO SPECTROMETER ONBOARD THE LANDER OF
CHANG’E-4 MISSION

Xinying Zhu, zhuxy@bao.ac.cn
National Astronomical Observatories of Chinese Academy of Sciences, Beijing, China: Chinese
Academy of Sciences (CAS)
Jianjun Liu, liujj@nao.cas.cn
National Astronomical Observatories of Chinese Academy of Sciences, Beijing, China: Chinese
Academy of Sciences (CAS)
Yan Su, suyan@nao.cas.cn
National Astronomical Observatories of China, University of Chinese Academy of Sciences,
Beijing, China: Chinese Academy of Sciences (CAS)
Weibin Wen, wenwb@nao.cas.cn
National Astronomical Observatories of Chinese Academy of Sciences, Beijing, China: Chinese
Academy of Sciences (CAS)
Junduo Li, lijd@nao.cas.cn
National Astronomical Observatories of Chinese Academy of Sciences, Beijing, China: Chinese
Academy of Sciences (CAS)

Chang’e-4 mission is consisted of three parts –lunar lander, lunar rover and relay satellite. The
relay satellite nicknamed QUEQIAO was launched to the halo orbit of the Earth-Moon Lagrange
Point L2 at 21:25 UTC ,May 20th,2018,and the Chang’e-4 lunar lander and rover successfully
landed in Von Karman crater on the far side of moon at 02:26 UTC,Jan 3rd 2019.The Low
Frequency Radio Spectrometer (LFRS) is a scientific payload onboard Change-4 lunar lander.
The primary motivation for LFRS is to learn about the universe through VLF spectral window
which is the only part of the electromagnetic spectrum yet to be completely explored. LFRS
will provide situ measurements of low frequency(100kHz40MHz) radio phenomenon in the
far-side of moon first time in human history. The noise from the Chang’e-4 lunar lander itself
is very intense, thus all target’s radio emissions are hidden in this noise. A method is proposed
in order to suppress the significance interference from the lander. A short correct antenna was
installed very close to the Lander near the 5m long LFRS antenna. The signals received from
the correct antenna are almost the noise from the lander, because the short correct antenna is
not so sensitive as the 5m long antenna to the target’s radio emissions. The signals received
from 5m long antenna will be corrected by the signals received from short correct antenna to
suppress the interference from the lander.In order to evaluate the performance of the LFRS, a
series of ground experiments are carried out using the LFRS prototype model. The results after
EMI mitigation show that the lower limit detection level of LFRS may be 10􀀀18Wm 􀀀2Hz 􀀀1:


see more here:

https://www.cospar-assembly.org/

[Phil Stooke]

Lunar day 17 just ended and the total distance now is 448 m (rounding up), 23 m during that day.

Phil

https://www.weibo.com/ttarticle/p/show?id=2...499316386431055

[Phil Stooke]

New data!

http://moon.bao.ac.cn/pubMsg/detail-CE42EN.jsp
-------------------------------
Chang'e 4 second scientific data is released
28 April 2020

On 28 April 2020, the Ground Research and Application System of Chinese Lunar Exploration Project released the second scientific data of Chang'e 4. The Chang'e 4 achieved humanity's first soft landing and in-site detection on the far side of the Moon, on 3 January 2019. Until March 2020, the Rover (Yutu-2) already finish the 16th lunar day scientific exploration, and achieved breakthrough of double 400, it means that the rover survives over 400 days and travels over 400 meters on moon's far side. At present, it carried out the 17th lunar day scientific exploration.

The Ground Research and Application System of the Chinese Lunar Exploration Project released scientific data acquired by 4 scientific payloads onboard Chang'e-4 lander, rover(Yutu-2) during the 3rd and 4th lunar day. A total of 1,471 data files, with a total data volume of 7.18 GB are released.
--------------------------------

This will include the VNIS data for the rock I have noted a name for in the map thread. Qi Yuan, translated in a journal article as 'unexpected encounter' or perhaps 'lucky encounter', but showing up in Google translate versons of recent Chinese press articles as 'Pocahontas'. I don't know where that comes from, but I note that the CE5 T1 return capsule which was named 'little flyer' got translated as 'Dumbo' because that was the name given to the well-known flying elephant in China.

Phil

[Xerxes]

Qi Yuan, translated in a journal article as 'unexpected encounter' or perhaps 'lucky encounter', but showing up in Google translate versons of recent Chinese press articles as 'Pocahontas'. I don't know where that comes from

Feng Zhong Qi Yuan (風中奇緣) "An Unexpected Encounter amidst the Wind" is the Chinese name of the Disney movie called "Pocahontas" in English. It certainly highlights the dangers of using computer-assisted translation without due caution. I wonder, though, if the Chinese scientists are intentionally choosing punny names for their sites.

[Phil Stooke]

Thanks for that useful information.

https://www.weibo.com/ttarticle/p/show?id=2...505533557113267

This link is to the Weibo notification that Yutu 2 woke up a few days ago, on its 500th day on the Moon. A couple of nice pictures. Also we learn that because the communications systems are being upgraded for the upcoming Mars mission, Yutu 2 will not drive this month but will 'detect' in place. VNIS might make repeated observations under different lighting conditions (my speculation). LPR will probably not accomplish anything by repeated use in one place so may not be used. The neutral atom instrument may still get good results. The lander might be able to operate as usual. A small crater nearby will be the next study site when Yutu 2 moves again.

Phil

[Phil Stooke]

My thoughts about what might be done during the 18th day were completely off. Only the neutron and radiation detector on the lander was operated. But just about now the Sun is rising on the lander and rover, so if they are to be used this month they should start tomorrow. I had heard that the work on communications systems was nearly finished a while ago, so with any luck Yutu 2 will be busy soon. The task will be to investigate a nearby crater just a few meters away, so possibly not a lot of driving this month.

Phil

[Phil Stooke]

Yutu 2 is back at work on day 19. Two images were released here:

https://www.weibo.com/ttarticle/p/show?id=2...516092918759681

And they fit together like this:

[Phil Stooke]

Perspective projection (approximate) of the above to help map tracks.

Phil

[Phil Stooke]

New data from CE4 and Yutu 2:

----------------------------------
13 June 2020
On 13 June 2020, the Ground Research and Application System of Chinese Lunar Exploration Project released the third scientific data of Chang'e 4. The Chang'e 4 achieved humanity's first soft landing and in-site detection on the far side of the Moon, on 3 January 2019. Until June 2020, the Rover (Yutu-2) already finish the 18th lunar day scientific exploration, and travels 447.68 meters on moon's far side.

The Ground Research and Application System of the Chinese Lunar Exploration Project released scientific data acquired by 4 scientific payloads onboard Chang'e-4 lander, rover(Yutu-2) during the 5th and 6th lunar day. A total of 1096 data files, with a total data volume of 6.11GB are released.The data is described in detail in the product description.

Lander:
LFRS Level 2C scientific Data
Rover:
PCAM Level 2B Scientific Data
LPR Level 2B Scientific Data
VNIS Level 2B Scientific Data
The Ground Research and Application System is one of five major systems of Chinese Lunar Exploration Project, it responsible for the lunar exploration data receiving, processing, managing and releasing. The GRAS Moon and Planetary data center provide data services and technical support.

Our contact information: lpdc@nao.cas.cn
---------------------------------

http://moon.bao.ac.cn/pubMsg/detail-CE43EN.jsp



Phil

[Phil Stooke]

On the Chinese 9ifly forum a user has posted news about Yutu 2. Currently snoozing through its mid-day nap, but in the 3 days (June 15-17) before the break Yutu 2 examined a small crater which had been seen to have light-toned material in and around it. It turns out to be a regolith breccia, or what was sometimes called 'instant rock' regarding Apollo samples - regolith converted to a loosely bound 'rock' by shock or bits of impact glass. It was broken apart by the rover's wheels. After the break they will move on again. Only 5 m of travel in that morning work session, maneuvering around the little crater to get VNIS on it.

No pictures of it yet.


http://9ifly.spacety.com/forum.php?mod=vie...page=3#lastpost

Phil

[Phil Stooke]

https://www.weibo.com/ttarticle/p/show?id=2...704170131498#_0


This article describes the activities of Yutu 2 during the 19th lunar day. A picture of tracks in it is part of a larger panorama taken with roughly mid-day lighting, with images released earlier:


https://www.weibo.com/ttarticle/p/show?id=2...092918759681#_0

That report describes the start of work on day 19, so the latest image is not from the end of the day and is either taken just as work started on day 19 or (my guess) on day 17 around the time of the mid-day break.

Here is a composite image of the tracks at that time.

Phil

[Phil Stooke]

Yutu 2 just woke up for the start of the 20th lunar day:

https://www.weibo.com/ttarticle/p/show?id=2...526870661038164

The article includes a discussion of a very interesting paper in Nature about deep structure revealed by the LPR:

https://www.nature.com/articles/s41467-020-17262-w


Editorializing for a minute, I really appreciate the level of information we get from China about this mission. Raw data releases, lots of papers, monthly details of driving and activities. Compare this with ISRO's record with Chandrayaan 2 - remember Chandrayaan 2? No, nor do I. And Luna 25 is supposed to fly next year - I wonder what we'll get from that.

Phil

[Phil Stooke]

End of lunar day 20! 28 m driven, for a total of 491 m. Not enough information yet for me to add to the map.

Phil

https://www.weibo.com/ttarticle/p/show?id=2...531382373187895

[John Moore]

The distance during day 20 is just under double that of day 19, which suggests, possibly, that the rover is still in good health, and that the terrain covered wasn't so challenging as to encounter such likes as awkward rocks or tiny craterlets to get stuck at.

John Moore