Updates China's Chang’e-4 Lunar Landing Mission

Soheil_Esy

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Mission Briefing
Launch date: Late 2018 June 2018
Launcher: CZ-3B (YXX) CZ-4C
Payload(Country): Chang'e 4(PRC) Relay satellite (中继通信卫星)
Launch site(Country): Xichang(PRC) Xichang(PRC)
Launch pad: LCX LCX
Status: Pending Pending
Orbit type and parameter: Cislunar Cislunar
Remark: Launch code 0X-XX
http://www.chinaspaceflight.com/satellite/Deepspace/CE-4/CE-4.html

China Plans First Ever Landing on the Dark Side of the Moon


19.05.2015


The mission, part of China’s Lunar Exploration Program (CLEP), plans to land the probe and accompanying rover on the far side of the moon.

"We are currently discussing the next moon landing site for Chang’e 4," Chief lunar exploration engineer Wu Weiren told China Central Television. "We probably will choose a site that is more difficult to land and more technically challenging. Other countries have chosen to land on the near side of the moon. Our next move probably will see some spacecraft land on the far side of the moon."

The Chang’e-4 will follow the Chang’e-3, a probe launched in 2013, which carried the Jade Rabbit rover to the lunar surface. Though currently immobile, Jade Rabbit still transmits data back to Earth, and Chang’e-4 would take on a different scientific role.

Much of the Moon’s far side is covered by the South Pole-Aitken basin, one of the largest impact craters in the solar system. If we associate the near side with the face of the happy-go-lucky Man in the Moon, the crater on the far side could have completely reshaped cultural mythologies if the synchronous orbit had been reversed. The Aitken basin could have made the moon appear to be an ominous eye in the sky. An ancient, eternal Big Brother. A body to be feared rather than worshipped.
1022336409.jpg

Topographical map of the South Pole-Aitken basin

It’s not called the "dark side" for nothing.

It is here that the Change-4 will land. Scientists are hoping that the same impact which formed the crater may have also partially excavated parts of the mantle. If those parts of the moon’s interior can be studied, it could offer one-of-a-kind insights into what the moon is made of and where it came from.

The basin would also be an ideal spot to place permanent radio telescopes. These could reach into the depths of space without interference from Earth’s transmissions or atmosphere.

A successful landing on the far side would also give the Chinese tremendous bragging rights. While the dark side of the moon has been observed by various probes, a landing has never been attempted, much less accomplished, largely because it’s more technically difficult.

Chang’e-4 is set to launch in 2020, but before that, Chang’e-5 will makes its way to the moon in 2017. That mission will return with lunar samples. The chronology discrepancy can be attributed to the fact that Chang’e-4 is technically the backup to Chang’e-3, and will keep that number identifier despite launching after Chang’e-5.

Beijing has also planned a mission to Mars. Set to launch sometime around 2020, that probe would also return to Earth with samples, which could be another first, depending on how the space race plays out.

Read more: http://sputniknews.com/science/20150519/1022336534.html

China unveils plans for far side Moon landing and hints at future ‘lunar base’

2015/07/16

The Chinese National Space Administration (CNSA) has outlined its early plans for putting a lander and rover on the far side of the Moon. No country has attempted such a mission before.

A presentation submitted to the United Nations Office for Outer Space Affairs (pdf) states that the robotic mission, currently named Chang’e-4, will launch in 2018 or 2019 and will include a relay satellite.

The paper notes key objectives as performing the ‘first soft landing on the lunar farside in human history’, demonstrating technologies of lunar data relay, landing and roving on complicated terrains of the lunar farside, and lunar night power generation, and a number of scientific goals.

The project will be open to cooperation with other countries and organisations, at the mission level, regarding equipment used, and telemetry, communication and data.

As well as providing a “detailed survey on lunar environment in order to lay a foundation for subsequent lunar exploration mission”, there is, most notably, a proposal for collaboration on “experimental verification for [a] lunar base”.

The CNSA and the European Space Agency (ESA) have been discussing potential cooperation for Chang'e-4, according to an official announcement (Chinese).

The far side of our celestial neighbour, sometimes (erroneously) referred to as the ‘dark side’ of the Moon, cannot be seen from Earth due to gravitational or tidal locking. It had never been observed until the Soviet Union’s Luna 3 probe sent back images in 1959.

Relaying to the 'dark side'

It was first revealed in May that Chang’e-4, a back-up to China’s 2013 Chang’e-3 mission involving a lunar lander and rover and the first 'soft-landing' on the Moon since the 1970s, would aim to soft-land on the lunar far side.

Chang’e-4 will be similar technically to Chang’e-3, but its exploration goals will be redesigned and the payload will be reconfigured.

The relay satellite will be launched first, and put into a halo orbit around the Earth-Moon L2 Lagrange point, a gravitationally balanced area.

The satellite would allow communication between Earth and the rover and lander, with a delay of around two seconds. China went some way to testing this with the service module of a test lunar return mission late last year.

B7InjP2IEAEPT-E.jpg


Prestige, prowess and science

As well as earning China a prestigious ‘first’ in space exploration – something that the country’s leaders would be keen to exploit – and demonstrate technical prowess, exploring the lunar far side is of immense scientific interest.

A large chunk of the Moon’s far side is covered by the South Pole–Aitken basin, a huge impact crater that may offer excavated lunar mantle, giving insights into how the Moon formed. Helium-3, an isotope that could possibly be used in future nuclear fusion reactors, is hypothesised to be found there in abundance.

The far side of the Moon has been gaining interest in recent years, having previously been popularised by the 1973 Pink Floyd album ‘The Dark Side of the Moon’.

Exploration of the far side was highly recommended for exploration in the influential 2013-2022 Decadal Survey, while Johann-Dietrich Woerner, the new Director General of ESA, recently proposed establishing a ‘Moon village’.

http://gbtimes.com/china/china-unveils-plans-far-side-moon-landing-and-hints-future-lunar-base





12 Oct 2015

China space admin chief Xu: Lunar sample return mission in 2017, lander on far side in 2018, lander/rover combination in 2020.

https://twitter.com/pbdes/status/653525359216959488

CE-4 lander and rover

12 Jan 2016

0

https://mmbiz.qlogo.cn/mmbiz/icZklJ...yonJL2FxxEauC6ibGNtV0KTRmSKU3dg/0?wx_fmt=jpeg
Chang'e-4 Lunar Rover
http://www.guokr.com/post/716318/



Both the CE-4 lander and relay satellite would be able to carry a small payload such as experiments conceived by students.

CYhtH_5UsAEZ1zR.png

https://pbs.twimg.com/media/CYhtH_5UsAEZ1zR.png
https://twitter.com/cnspaceflight/status/686918943672373248


Requirements:

1. Mass: Total mass of the single payload not exceeding 3kg.

2. Vacuum: the ability to withstand and operate in a vacuum environment.

3. Temperature: short-term work must withstand -80 ℃ ~ + 80 ℃ temperature environment. Over the long-term Moon night must be able to withstand -180 ℃ ~ + 80 ℃ temperature environment.

4, Volume: Volume constraints with different installation location varies, not in this particular provision.

5. Power: operating power should be controlled as far as possible within the 20 W.

Chang'e-4 mission objectives is to achieve a soft landing on the far side of the Moon and achieve a Earth-Moon L2 point relay communication, in place to carry out detection, detection and patrol surrounded the Earth-Moon L2 point detection, and detection data processing and analysis. Side of the moon in order to achieve a soft landing and automatic inspections investigation as symbol of success.

https://twitter.com/cnspaceflight/status/686918943672373248


Sino-Russian cooperation

2015-Sep-10

The two sides agreed to cooperate in the field of lunar exploration and Mars, and Russia hopes to take the opportunity to equipped with Russian scientific instruments, China's Chang'E-4 lunar probe. The two sides will study the technical feasibility.

http://www.miit.gov.cn/n11293472/n11293832/n11293907/n11368223/16831220.html

2016-01-17

Russia will cooperate with Chang'e-4 lunar dust measuring instrument

The lunar rover could carry a Swedish neutral particle detection instrument

At the same time, some instruments will be removed, including the lander's optical telescope and extreme ultraviolet camera, the rover's particle induced X-ray spectrometer.

http://china.cnr.cn/xwwgf/20160117/t20160117_521156107.shtml

12 Oct 2015

China space chief Xu: Lunar & Mars explore progressing side by side w/ us. We're open to partners, especially in far-side lunar mission.

https://twitter.com/pbdes/status/653531440227946497

CE-4 relay satellite


2015-12-31

Relay orbits about the Earth-Moon collinear libration point shave significant value on the exploration of the lunar farside, but have complex kinetic characteristics in the nature, thus the orbit maintenance has always been focused in the deep space navigation and control field. This paper explores orbit maintenance technology of the relay orbit about the collinear Earth-Moon libration points under the real dynamical conditions. First, based on the restricted three-body problem, the mathematic model of relay orbit station-keeping with the real dynamical model is analyzed. The continue-circling method is presented for the relay orbit maintenance with the two control styles, i.e., the Halo style and the Lissajous style. Second, with the third-body gravitation and the solar radiation pressure perturbations considered, the method is tested and analyzed by using the numerical simulations to achieve the control frequency and the corresponding velocity increment required by the relay orbits with different amplitudes. According to the simulations, the Lissajous style is suitable to the orbit maintenance with a control interval of 7.4 days and a velocity increment less than 20 m/s/a. Furthermore, the method has been successfully applied in Chang'e-2 and Chang'e-5T1 extended missions and can provide a beneficial reference for the future Chang'e-4 mission.

1451910926232002.1452698879.png

http://www.chinaspaceflight.com/usr/uploads/2016/01/04/1451910926232002.png
http://www.chinaspaceflight.com/satellite/Deepspace/CE-4/CE-4.html

http://jdse.bit.edu.cn/sktcxbcn/ch/reader/view_abstract.aspx?file_no=20150404&flag=1

 
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Nicholas Kang

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The mission's first phase will begin in less than a day! The Chinese will launch a communication relay satellite, called Queqiao, to an Earth-Moon L2 Halo orbit tomorrow.

change-4-relay__1.jpg

This will be followed by a launch of the real lander probe in 6 months time.

Liftoff is scheduled to take place at around 5 p.m. EDT (21:00 GMT) Sunday, May 20, 2018. Queqiao will ride to space atop a Long March 4C rocket launched from the Xichang Satellite Launch Center in China’s Sichuan Province. Two smaller radio astronomy satellites, known as DSLWP-A1 and A2, will piggyback on the mission.

The 425 kg relay satellite is based on the three-axis stabilized CAST-100 small satellite bus featuring an 130 N hydrazine propulsion system. It carries a deployable 4.2 m dish antenna for the relay equipment. It provides four 256 kBps X-band links between itself and the lander/rover and one 2 MBps S-band link towards earth.

Besides the relay function, the spacecraft also carries a Low-frequency radio detector to provide radio-sky images, and frequency dependence of radio in the very low frequency band and to perform low-frequency radio astronomical observations.

In general, Queqiao is expected to be operational for at least five years.

1484596149160190.jpg.db44ac0c563cf6ad853b7eba4c084ec1-655x606.jpg

China also has its cubesats going to the Moon (Entering lunar orbit!)

dslwp-a1__1.jpg

Built by the Harbin Institute of Technology, DSLWP-A1 and DSLWP-A2, which stands for “Discovering the Sky at Longest Wavelengths Pathfinder,” are two identical micro-satellites weighing approximately 99 pounds (45 kilograms) each. Nicknamed Longjiang-1 and Longjiang-2 (meaning “dragon river”), the satellites are planned to be inserted into a lunar orbit at an altitude of 124 by 5,592 miles (200 by 9,000 kilometers).

If everything goes as planned, the twin micro-satellites should be able to conduct ultra-long-wave astronomical observations of the sky at frequencies between one megahertz and 30 megahertz. Chinese scientists hope that observations performed by DSLWP-A1 and A2 will provide insight into the nature of energetic phenomena from celestial sources. Additionally, the probes are also designed to be available for amateur radio tests.

The Long March 4C booster that is being used for Sunday’s launch has an estimated liftoff mass of 250 metric tons. It is 150 feet (54.7 meters) in tall with a diameter of 11 feet (3.4 meters) and is capable of delivering payloads of up to 4.2 metric tons into a low-Earth orbit , 2.8 metric tons into a Sun-synchronous orbit, and up to 1.5 metric tons into a geostationary transfer orbit.

Note: Most of the Chinese spaceflight research articles regarding the Chang'e-4 mission are published here. (Unfortunately, most of them are in Chinese, except the abstract of the articles. Let me know if you need some translation service. :p)

News Source:

SpaceflightInsider.com, Nasaspaceflight.com, XinHuanet, Gunter's Space Page, The Planetary Society
 

Nicholas Kang

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A successful launch! Confirmed all microsats and Queqiao separated and on their way to the Moon!

[ame="https://twitter.com/AJ_FI/status/998330680810573825"]Andrew Jones on Twitter: "Chang'e-4: Main space programme contractor CASC confirms successful launch and insertion in lunar transfer orbit for the #Queqiao relay satellite… https://t.co/zNclxQom1F"[/ame]

index.php


1526855157934_125_1440x1081.jpg


1526855183778_810_1440x1080.jpg

Launch video:

[ame="https://www.youtube.com/watch?v=8bHeWdw-PHM"]Long March-4C launches Queqiao (Chang'e-4 relay satellite/ 鹊桥) - YouTube[/ame]

(As always, Chinese launches are secretive... The links below have been verified. Click the "x" button to close the ad and enjoy the launch. Will see if I can find a bigger-screen version.)

https://v.qq.com/x/page/h0660vjgtd5.html

https://www.yizhibo.com/l/gFg-lYQyXLtpJFYS.html

Ah, even the Saudis are watching! :lol:

[ame="https://twitter.com/saudiatv/status/998328024692133888"]قناة السعودية 🇸🇦 on Twitter: "🇸🇦
عاجل | انطلاق الرحلة ال�ضائية الصينية لاستكشا� القمر بمشاركة المملكة العربية السعودية.

#السعودية_تستكش�_القمر
#قناة_السعودية… https://t.co/lpdX5x6PAc"[/ame]

And here is how Queqiao looks like before launch:

[ame="https://twitter.com/AJ_FI/status/998339540715823104"]Andrew Jones on Twitter: "And the 448 kg Queqiao Chang'e-4 relay sat before launch… "[/ame]

Mission Profile:

mmexport1526856079137.gif

Rocket Launch

mmexport1526856081611.gif

Satellite Separation

mmexport1526856084461.gif

Deployment of antenna

mmexport1526856087882.gif

Heading towards the Moon!

mmexport1526856090619.gif

In Earth-Moon L2 Halo orbit

mmexport1526856093708.gif

Communication relay from Moon to Earth

mmexport1526856097531.gif

Communication relay between the lander probe (to be launched 6 months from now) while in landing phase and the ground communication station on Earth

mmexport1526856100514.gif

Communication relay between the lander probe (to be launched 6 months from now) while on the Moon and the ground communication station on Earth​

Links:

gbtimes.com, CCTV news, nasaspaceflight.com
 
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4throck

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Very interesting mission with the communications satellite.
I hope the rover / lander performs better than on the previous mission.
And I hope that we get some decent images, not photos of a TV screen :hmm:
 

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Lunar fly-by successful!

[ame="https://twitter.com/aj_fi/status/1000008862659948545"]Andrew Jones on Twitter: "#queqiao Chang'e-4 satellite is right now (13:41 UTC/ 09:41 EDT/ 21:41 BJT) expected to flyby the Moon at ~110 km above the surface & head to E-M Lagrange point 2, after a braking manoeuvre. Hopefully we'll get actual updates from China before too long. https://t.co/fV3RrSYDBs"[/ame]

%E2%80%9C%E9%B9%8A%E6%A1%A5%E2%80%9D%E4%B8%AD%E7%BB%A7%E6%98%9F%E6%88%90%E5%8A%9F%E5%AE%9E%E6%96%BD%E8%BF%91%E6%9C%88%E5%88%B6%E5%8A%A8.gif

The perilune was 100 km and a short burn was commenced for mid-course correction to bring QueQiao to EML2 halo transfer orbit at 21:32 GMT+8 (13:32 UTC) yesterday.

The Beijing Flight Mission Control Center received confirmation that the spacecraft was on track towards EML2 on 21:46 GMT+8 (13:46 UTC).

Now, the spacecraft is in the EML2 transfer orbit and will remain so for the next 4 days before beginning the EML2 halo orbit insertion maneuver.

Source: gbtimes.com, spaceflightfans.cn
 

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Some updates from the 2 moon cubesats.

DSLWP-B has entered moon orbit, but DSLWP-A's UHF downlink seems to be offline

The cubesats tracking documents and software can be found here:

https://github.com/bg2bhc/dslwp_doc

(Have a look at the PDF. It is bilingual with English translation readily available and it involves some Linux computing.)
 

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Successful launch!


Interesting trajectory analysis for astrodynamicists!

Andrew Jones' Tweets provide more information on the Chang 'E 4 mission.

[ame="https://twitter.com/AJ_FI/status/1030181485507235840"]Andrew Jones on Twitter: "China's mission to the far side of the Moon is set to launch in December. Here's some Chang'e-4 background, landing site intrigue, new images of the lander & rover, secondary mission updates and more: https://t.co/oBf5fW74BO… https://t.co/EV5QWzgiJc"[/ame]

[ame="https://twitter.com/AJ_FI/status/1071158225666539521"]Andrew Jones on Twitter: "Here's some cool shots of the Chang'e-4 rover, which remains nameless, despite and whole public contest and voting and whatnot.… https://t.co/QM8lNqDD1Y"[/ame]

[ame="https://twitter.com/AJ_FI/status/1071152773322948608"]Andrew Jones on Twitter: "Chang'e-4 is on the way to the Moon after successful trans-lunar injection. Landing in Von Kármán crater on far side of the Moon expected in early January https://t.co/cyoEJ5Eg0V"[/ame]

[ame="https://twitter.com/AJ_FI/status/1071123043412570112"]Andrew Jones on Twitter: "Launch of Chang'e-4 has officially be declared a success and the spacecraft are on their way to the Moon! https://t.co/ltOW78fy0b… https://t.co/eNQr7ubxTH"[/ame]

[ame="https://twitter.com/AJ_FI/status/1071116164133195779"]Andrew Jones on Twitter: "While we wait for confirmation (or otherwise...) of launch and TLI success, here's a closer look at the launch of Chang'e-4. Source: https://t.co/7JfLUM65IK… https://t.co/ZGfcPOZPWs"[/ame]

[ame="https://twitter.com/AJ_FI/status/1071111011380412416"]Andrew Jones on Twitter: "Here's a replay of the launch from the unofficial stream… "[/ame]
 

Nicholas Kang

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And...

Chang'e-4 lander makes contact with Queqiao relay satellite from lunar orbit.

Chang'e-4 is expected to make its landing attempt in the South Pole-Aitken Basin in early January.

Source: gbtimes
 

Thunder Chicken

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[ame="https://twitter.com/b0yle/status/1080660740258844673"]Chinese TV posted a Tweet indicating soft landing confirmed, but that Tweet has been removed.[/ame]


Lots of noise and tweets, but nothing official yet. Hopefully all went well. :/
 

4throck

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I love those surface images with the colors completely off and heavy vignetting :p
Chang'e 3 was also like that!
They could easily correct it on released images but it's kind of fun to see the moon like this.

6780003.jpg

http://www.cnsa.gov.cn/n6759533/c6805034/content.html

(this is not a negative view on the mission or the raw images, just commenting on their particular look)

---------- Post added at 18:30 ---------- Previous post was at 10:11 ----------

Rover:

6780030.jpg

http://www.cnsa.gov.cn/n6759533/c6805052/content.html
 
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Landing Site Location, and current position of lander and YUTU-2

Took a while to figure this out, but I did.

I finally located the *exact* landing spot of Chang'e-4, after analyzing the recently released landing video. The image below is taken from the LROC WMS site, using using higher resolution NAC overlay. The exact landing spot is in the center of the green dashed circle, with the coordinates of latitude -45.456, and longitude of 177.588 (see info box on the left side).

Why do I know this? I analyzed the Chang'e-4 landing video, and I realized the difficulty I had before was because the orbital path of the lander (at the far side) was actually NORTH to SOUTH! :) So I basically downloaded the video, and turned it UPSIDE DOWN and watched it this way, while looking at the LROC WMS for familiar patterns, and I found it...check the 2nd photo... this shows landing approach, and if you watch the video again, you'll see that the lander will land on that cluster of craters, the pattern of which matches the LROC WMS NAC image. :)

Remember, if you watch the video again, it's all UPSIDE DOWN with reference to the LROC images of the area, due to the fact that the lander was coming into Von Karman from the north to the south!

Landing site analysis vis-a-vis the panoramic shot. Note encircled craters and match them with the encircled craters in the (partial) panoramic image. CHG is the position of the lander, then the green dotted line to "1" is the initial curved path of YUTU-2 rover which can be seen in the panoramic shot. The sky blue path to "2" is the later path of the rover to its (possible) present location, based on the recent "taking photos of each other" images recently released by the Chinese space agency. Note that YUTU-2's position at "2" has a small crater in the background. That tiny crater is also visible on the first image that shows the landing site.

I also took into account the Sun/shadow angles and they do correspond with the approx. time these images were captured, based on coordinates of the lander on the lunar surface.

-RODION
 

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4throck

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I wonder if NASA or ESA would be "bold" enough to carry biological samples to the Moon.
They now have "planetary protection" guidelines to prevent "contamination".
Scientific mysticism at its best...
 

Notebook

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The plants are in a sealed container on board the lander. The crops will try to form a mini biosphere - an artificial, self-sustaining environment.
On Tuesday, Chinese state media said the cotton seeds had now grown buds.

[ame="https://www.youtube.com/watch?v=05-qogh7GA0"]Thing from another World - 1951 - Official Trailer - YouTube[/ame]

That's all we, need a fruit-fly/potatoe/cotton hybrid.


N.
 
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