Tag: Chang’e 4

Chang’e-4/Yutu-2 return to dormant mode for lunar night

8:59 am

According to one story in the Chinese press today, the science teams running Chang’e-4 and Yutu-2 on the far side of the Moon have now put both into dormant mode for the coming lunar night after completing their seventh lunar day.

What is intriguing about this short story is that while to lauds the work done by Chang’e-4 during that seventh lunar day, it says nothing about Yutu-2. Early comparable reports would have at least told us how far the rover moved during the lunar day. This time they say nothing at all about Yutu-2, other than it has been placed in dormant mode.

It could very well be that they had a problem with the rover. Sadly, China is not an open society. We can only wait for them to tell us.

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The travels of China’s Yutu-2 rover on the Moon

9:34 am

Yutu-2 and Chang'e-4
Click for full image.

The Lunar Reconnaissance Orbiter (LRO) science team today released images that track the travels of China’s lunar rover Yutu-2 from its landing on January 30, 2019 through June 3, covering the rover’s first six lunar days on the Moon.

The image to the right, cropped, reduced, and annotated to post here, shows the relative positions of both spacecraft as of June 3, 2019. In the release they also included a gif movie showing the progression of Yutu-2’s movements since landing.

Once a month, LRO passes over the Chang’e 4 landing site, allowing LROC to capture a new image. LROC has now imaged the site five times (since the landing) and observed Yutu-2 to have traveled a total of 186 meters (distance measured using the rover tracks). If you squint, portions of the rover tracks are visible as a dark path in the images from April, May, and possibly June.

table of Yutu-2's movements through June 2019

The LRO release also included a table showing the distance Yutu-2 has traveled with each lunar day, shown on the right. The table does not include the 23 meters (75 feet) the rover traveled on its sixth lunar day. My estimate yesterday that Yutu-2 was traveling an average of about a 100 feet per day, with the distances per day shrinking with time, seems largely correct. During the rover’s fourth and fifth lunar days it moved very little, either because they had found something very interesting they wanted to inspect more closely, or they were moving more cautiously as the rover’s life extended past its planned lifespan of three lunar days.

On the sixth day however they increased their travels again, suggesting that either they had finished the observations at the previous location, or they had gained more confidence in the rover’s staying power.

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Chang’e-4 and Yutu-2 awake for 7th lunar day

8:42 am

The new colonial movement: Chinese engineers have awakened both the Chang’e-4 lander and the Yutu-2 rover to begin work on their seventh lunar day on the Moon’s far side.

The text of this Chinese news report is almost identical to the text in the news report a month ago, when both spacecraft were awakened for the sixth lunar day. And as before, it tells us little.

What today’s story reveals is that Yutu-2 traveled only about 75 feet during the sixth lunar day. With an overall odometer reading of 695 feet, it appears it is averaging about 100 feet per lunar day, with the per day number dropping with time. Either the science team is becoming cautious, or they have had unstated issues that have slowed them down.

Still, the rover’s nominal mission was only three lunar days, so it is survived more than twice as long as designed.

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Chang’e-4 and Yutu-2 wake up for sixth lunar day

8:29 am

China’s Chang’e-4 lander and Yutu-2 rover have been reactivated this week to begin observations during their sixth lunar day on the far side of the Moon.

According to the Chinese news source,

For the sixth lunar day, the lander’s neutron radiation detector and low-frequency radio detector will be restarted to conduct scientific tasks including particle radiation observation and low-frequency radio astronomical observation.

The rover’s panoramic camera, detection radar, infrared imaging spectrometer and neutral atom detector will be restarted during the sixth lunar day.

That’s about all we know. They have not released much information about the rover’s travels, nor have they released any detailed information about the data they have obtained.

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Yutu-2 travels more than 600 feet during its fifth lunar day on the Moon

8:35 am

The Chinese press today revealed that during its fifth lunar day on the Moon’s far side China’s lunar rover Yutu-2 traveled about 623 feet.

Where exactly it went, and what it learned, they did not reveal. We will have to wait for Lunar Reconnaissance Orbiter images to learn the rover’s route.

They have now put both Yutu-2 and the lander Chang’e-4 into sleep mode for the long lunar night.

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Chang’e-4 and Yutu-2 awaken for fifth lunar day

9:35 am

The new colonial movement: China’s lunar lander Chang’e-4 and rover Yutu-2 have been awakened to begin work for their fifth lunar day on the far side of the Moon.

According to the report from this official Chinese government news source, Yutu-2 has now traveled just under 600 feet from the lander. We know from Lunar Reconnaissance Orbiter (LRO) images taken during the rover’s second lunar day of travel that it had moved to the west, but we don’t really know much else beyond that. LRO has not released any new images, and the Chinese have not told us.

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Yutu-2 and Chang’e-4 awake for fourth lunar day

8:43 am

The Chinese rover Yutu-2 and lander Chang’e-4 were awakened on March 30, 2019 to begin work for their fourth lunar day on the surface of the Moon’s far side.

The rover was designed to last for three lunar days, but much like NASA missions that regularly outlive their initial mandates, Yutu 2’s mission may stretch on longer, the Chinese space agency hopes. (The current rover’s predecessor, Yutu, lost its roving ability on its second day on the moon.)

The China Lunar Exploration Program, which heads up the mission, has not provided any details about its scientific plans for the fourth day of Chang’e 4, which is focused on exploring the far side of the moon and how it differs from the near side.

Based on the images taken by Lunar Reconnaissance Orbiter, it appears they will be heading west, following the smoothest route away from Chang’e-4. This will place Yutu-2 in an area of small craters.

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Yutu-2 heads west!

10:28 am

LRO images of Yutu-2 on the Moon
Click for full image.

A new image from Lunar Reconnaissance Orbiter (LRO) shows the path taken by the Chinese lunar rover Yutu-2 during its second lunar day of travel on the Moon. The LRO images on the right, cropped and reduced in resolution to show here, compares the rovers position at the start and end of February. The white arrow indicates the rover, with its Chang’e-4 lander visible between the three craters to the east. As noted by the LRO science team:

LRO passes over any given place on the Moon at least once every month (in the daylight), allowing the westward progress of the Yutu-2 rover to be seen. At the end of February, Yutu-2 was 69 meters from it’s home base, the Chang’e 4 lander; LROC images show Yutu-2 made 46 meters of westward progress during the month of February.

It appears from these orbital images that they are taking the smoothest route, with the fewest obstacles, away from the lander.

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Chinese lunar rover and lander enter their third lunar night

9:21 am

The Chinese lunar rover Yutu-2 and its lander Chang’e-4 have gone into hibernation as they enter their third lunar night on the far side of the Moon.

According to Chinese news reports, both spacecraft have now exceeded their nominal lifespan.

With all systems and payloads operating well, the Yutu-2 team will continue roving and science data collection on lunar day 4 of the Chang’e-4 mission, according to a [Chinese] announcement.

Yutu-2 added 43 meters to its overall drive distance in its third day of activities, continuing a path to the northwest of the landing site, which was recently named ‘Statio Tianhe’ by the International Astronomical Union. The rover just covered seven meters between waking for lunar day 3 on Feb. 28 and Mar. 3, during which time it navigated carefully toward a 20 centimeter diameter rock in order to analyze the specimen with an infrared and visible light spectrometer to determine its origin.

I am struck by how tentative the Chinese and their rover appear. The first Russian lunar rover, Luna 17, traveled 6.5 miles in eleven months. The second, Luna 21, traveled 23 miles in four months. At the pace Yutu-2 is setting, it will not come close to these mileages. Moreover, my impression of Chinese space technology in the past decade has been that it is quite robust. This tentativeness thus surprises me. Maybe because this is a government project they are simply covering their butts should something go wrong, and thus making believe the rover is more delicate than it really is.

As Scotty on Star Trek once said, “Always under predict, then over perform.” We might be seeing that pattern here.

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Rover update: February 20, 2019

1:52 pm

Summary: Curiosity in the clay unit valley. Opportunity’s long journey is over. Yutu-2 creeps to the northwest on the Moon’s far side.

For the overall context of Curiosity’s travels, see my March 2016 post, Pinpointing Curiosity’s location in Gale Crater.

For the updates in the past year go here. For a full list of updates before February 8, 2018, go here.

Curiosity

Curiosity's view to the east on Sol 2316
Click image for full resolution version

Overview of Curiosity's future travels
Click image for original image

Since my January 22, 2019 update, Curiosity finally drove down off of Vera Rubin Ridge into a valley between the ridge and the lower slopes of Mt Sharp. The Mars Reconnaissance Orbiter (MRO) overview on the right has been annotated by me to show the rover’s travels (shown by the yellow dotted line), with its proposed route indicated by the red dotted line. The yellow lines indicate approximately the terrain seen in the panorama above. The panorama was created from images taken on Sol 2016.

The valley that Curiosity is presently traversing is dubbed “the clay unit” or “the clay-bearing unit” by the geologists, based on its make-up determined from orbital data. So far they have found this terrain to be “some of the best driving terrain we’ve encountered in Gale Crater, with just some occasional sandy patches in the lee of small ridges.” Initially they had problems finding any rocks or pebbles large enough for the instruments to use for gathering geological data. For the past week or so, however, they have stopped at “bright exposure of rock” where some bedrock was visible, giving them much better material to work with.
» Read more

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New LRO image of Chang’e-4 and Yutu-2

10:05 am

Chang'e-4 and Yutu-2

The Lunar Reconnaissance Orbiter (LRO) science team has released its third and best image of the Chinese Chang’e-4 lander and Yutu-2 rover. The image on the right is a full resolution cropped section, with the lander on the bottom and the rover above and to the left.

Just after midnight (UTC) on 1 February 2019 LRO passed nearly overhead the Chang’e 4 landing site. From an altitude of 82 kilometers the LROC Narrow Angle Camera pixel scale was 0.85 meters (33 inches), allowing a sharper view of the lander and Yutu-2 rover. At the time the rover was 29 meters northwest of the lander, but the rover has likely moved since the image was acquired. This view has close to the smallest pixel size possible in the current LRO orbit. In the future however, LROC will continue to image the site as the lighting changes and the rover roves!

These future LRO images will allow us to track Yutu-2 and get an idea of its research, even if the Chinese do not release any information.

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IAU approves China’s proposed names for Chang’e-4 landing site

10:07 am

That was fast! The International Astronomical Union (IAU) has approved all of the proposed names that China submitted for the features at or near Chang’e-4 landing site.

The IAU Working Group for Planetary System Nomenclature has approved the name Statio Tianhe for the landing site where the Chinese spacecraft Chang’e-4 touched down on 3 January this year, in the first-ever landing on the far side of the Moon. The name Tianhe originates from the ancient Chinese name for the Milky Way, which was the sky river that separated Niulang and Zhinyu in the folk tale “The Cowherd and the Weaver Girl”.

Four other names for features near the landing site have also been approved. In keeping with the theme of the above-mentioned folk tale, three small craters that form a triangle around the landing site have been named Zhinyu, Hegu, and Tianjin, which correspond to characters in the tale. They are also names of ancient Chinese constellations from the time of the Han dynasty. The fifth approved name is Mons Tai, assigned to the central peak of the crater Von Kármán, in which the landing occurred. Mons Tai is named for Mount Tai, a mountain in Shandong, China, and is about 46 km to the northwest of the Chang’e-4 landing site.

Compare this fast action with the IAU’s approval process for the names the New Horizons team picked for both Pluto and Ultima Thule. It took the IAU more than two years to approve the Pluto names, and almost three years to approve the Charon names. It is now almost two months after New Horizons’ fly-by of Ultima Thule, and the IAU has not yet approved the team’s picks for that body.

Yet it is able to get China’s picks approved in less than a month? Though it is obviously possible that there is a simple and innocent explanation for the differences here, I think this illustrates well the biases of the IAU. Its membership does not like the United States, and works to stymie our achievements if it can. This factor played a part in the Pluto/planet fiasco. It played a part in its decision to rename Hubble’s Law. And according to my sources, it was part of the background negotiations in the naming of some lunar craters last year to honor the Apollo 8 astronauts.

The bottom line remains: The IAU has continually tried to expand its naming authority, when all it was originally asked to do was to coordinate the naming of distant astronomical objects. Now it claims it has the right to approve the naming of every boulder and rock anywhere in the universe. At some point the actual explorers are going to have to tell this organization to go jump in a lake.

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Chang’e-4 & Yutu-2 enter sleep mode for second lunar night

9:40 am

The Chinese lunar lander Chang’e-4 and its rover Yutu-2 have both gone into hibernation as part of their preparation for surviving their second night on the Moon’s surface.

The Yutu-2 rover and lander will resume science and exploration activities on Feb. 28 and March 1, respectively, according to the release, with the rover needing to unfold solar panels and dissipate heat.

The previous lunar night saw the Chang’e-4 lander record a temperature low of -190 degrees Celsius (-310 Fahrenheit), with measurements made possible by a Russian-developed radioisotope thermoelectric generator which also acts as a prototype for future deep-space exploration.

Official updates on the progress of the mission had been sparse during the second lunar day of operations, though some new images and footage were released ahead of the Chinese New Year holiday, which ran from Feb. 4 to Feb. 10.

Yutu-2 has traveled about 400 feet so far.

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LRO spots Chinese lunar rover

10:31 am

Yutu-2 and Chang'e-4 on far side of Moon

The Lunar Reconnaissance Orbiter (LRO) science team has now released a second and closer image of Chang’e-4’s location on the far side of the Moon, which now also shows the nearby rover Yutu-2.

The two arrows in the image to the right, cropped to post here, show both. The rover is the dot on the right, with the lander to the left, both just beyond the arrow tips. Both are very small, with Yutu-2 for example only two pixels across. Still, with both you can see their shadows, equally small, to the left of both bright dots. With sunlight coming from the right, all the craters, which are recessed, have their shadows on the right. The spacecraft, sticking up from the surface, have shadows going to the the left.

As Yutu-2 continues its travels, LRO will likely take more images, allowing us to track it even if the Chinese provide limited information.

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Chinese cubesat snaps picture of Earth and Moon from deep space

9:21 am

The Moon and Earth

A interplanetary cubesat, Longjiang-2, launched with China’s communications relay satellite that they are using to communicate with Chang’e-4 and Yutu-2 on the far side of the Moon, has successfully taken a picture of both the Moon and Earth, as shown in the picture on the right.

Longjiang-2 is confirming what the MarCo cubesats proved from Mars, that cubesats can do interplanetary work.

And the picture is cool also. This was taken on February 3, when the entire face of the Moon’s far side is facing the Sun, illuminating it all. This timing also meant that the globe of the Earth would be entirely lit.

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LRO photographs Chang’e-4 on lunar surface

9:00 am

Chang'e-4 on the lunar surface

The Lunar Reconnaissance Orbiter (LRO) science team has released a spectacular oblique image that shows Chang’e-4 on the floor of Von Kármán crater.

Four weeks later (30 January 2019), as LRO approached the crater from the east, it rolled 70° to the west to snap this spectacular view looking across the floor towards the west wall. Because LRO was 330 kilometers (205 miles) to the east of the landing site, the Chang’e 4 lander is only about two pixels across (bright spot between the two arrows), and the small rover is not detectable. The massive mountain range in the background is the west wall of Von Kármán crater, rising more than 3000 meters (9850 feet) above the floor.

The image on the right has been reduced to post here. If you click on it you can see a larger version, but you need to download a very large file at the above link to see it at full resolution.

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Planetary rover update: January 22, 2019

12:06 pm

Summary: Curiosity begins journey off of Vera Rubin Ridge. Opportunity’s silence is now more than seven months long, with new dust storms arriving. Yutu-2 begins roving the Moon’s far side.

Before providing today’s update, I have decided to provide links to all the updates that have taken place since I provided a full list in my February 8, 2018 update. As I noted then, this allows my new readers to catch up and have a better understanding of where each rover is, where each is heading, and what fascinating things they have seen in the past few years.

These updates began when I decided to figure out the overall context of Curiosity’s travels, which resulted in my March 2016 post, Pinpointing Curiosity’s location in Gale Crater. Then, when Curiosity started to travel through the fascinating and rough Murray Buttes terrain in the summer of 2016, I stated to post regular updates. To understand the press releases from NASA on the rover’s discoveries it is really necessary to understand the larger picture, which is what these updates provide. Soon, I added Opportunity to the updates, with the larger context of its recent travels along the rim of Endeavour Crater explained in my May 15, 2017 rover update.

Now an update of what has happened since November!
» Read more

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Update on Chang’e-4 plant experiments

5:32 pm

Link here. It appears the plant experiment has now run its course, designed as it was to end before the arrival of the first lunar night.

The experiment’s chief designer, Xie Gengxin of Chongqing University, told Xinhua that life inside the canister would not survive the lander’s first lunar night, which started on Sunday. The moon’s nighttime period lasts for about two Earth weeks.

It also appears that though the plant experiment included potato, cotton, and oilseed rape, only the cotton seeds spouted. China has only released a limited amount of information about this research, so to get further details we will likely have to wait for the published papers.

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Seeds sprout on Chang’e-4

9:01 am

The new colonial movement: The cotten seeds in a plant experiment on Chang’e-4 have now sprouted, becoming the first biological life to grow on the Moon.

On Tuesday, Chinese state media said the cotton seeds had now grown buds. The ruling Communist Party’s official mouthpiece the People’s Daily tweeted an image of the sprouted seed, saying it marked “the completion of humankind’s first biological experiment on the Moon”.

Fred Watson, Australian Astronomical Observatory’s astronomer-at-large, told the BBC the development was “good news”. “It suggests that there might not be insurmountable problems for astronauts in future trying to grow their own crops on the moon in a controlled environment. …I think there’s certainly a great deal of interest in using the Moon as staging post, particularly for flights to Mars, because it’s relatively near the Earth,” Mr Watson said.

Prof Xie Gengxin, the experiment’s chief designer, was quoted as saying in the South China Morning Post: “We have given consideration to future survival in space. Learning about these plants’ growth in a low-gravity environment would allow us to lay the foundation for our future establishment of space base.” He said cotton could eventually be used for clothing while the potatoes could be a food source for astronauts and the rapeseed for oil.

This experiment is actually a very big deal, as it is the first biological experiment, ever, to take place in a low gravity environment. All previous plant experiments in space have taken place in zero gravity, and thus failed to tell us anything about growth in a partial Earth gravity environment.

That the seeds have sprouted only tells us that they can. What we don’t know yet is if the low lunar gravity distorts their growth.

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LRO pinpoints Chang’e-4 landing site

11:16 am

LRO pinpointing Chang'e-4's location on Moon

By referencing the footage released by China of Chang’e-4’s descent onto the Moon, the Lunar Reconnaissance Orbiter (LRO) team has been able to pinpoint exactly where the lander touched down. The image on the right has been reduced slightly. Click on it to see it in full resolution.

The largest nearby crater to the lander is estimated to be about 80 feet across.

Because the images were in December 2018 before the lander’s arrival, they do not show it. However, the LRO team now knows exactly where to look when they take new pictures in the next few weeks. Moreover, this will allow them to monitor Yutu-2’s travels as it roves the surface over the coming months.

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Want to see a panorama of Chang’e-4 landing site? You can!

8:36 am

If you want a really good look at the Chang’e-4 landing site on the far side of the Moon — with Yutu-2 about thirty feet away — photographer Andrew Bodrov has produced a spectacular 360 degree panorama from images sent down by the lander.

This panorama reveals two things. First, the lander landed close to two small craters, which it thankfully missed. Second, there are some hills in the distance which I suspect are central peaks of Von Kármán crater. They are probably beyond Yutu-2’s range, but would make a worthwhile exploratory target.

Meanwhile, the rover and lander have come back to life after a brief hibernation to protect them from the heat of the lunar mid-day.

Finally, China has released a video showing Chang’e-4’s descent and landing, which I have embedded below the fold. In it, you can see the spacecraft computer maneuver to land between those two craters shown in the panorama.
» Read more

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Using LRO to find Chang’e-4

8:49 am

LRO image of Chang'e-4 landing area

The Lunar Reconnaissance Orbiter (LRO) science team has released a high resolution image from 2010 pinpointing the area on the floor of Von Kármán crater where Chang’e-4 landed. On the right is a reduced and partly annotated version.

They have not actually found the lander/rover, since this image was taken long ago before Chang’e-4 arrived. However, this image, combined with the Chang’e-4 landing approach image, tells us where the lander approximately landed. It also pinpoints where to look for it when LRO is next able to image this region, around the end of January.

By then, Yutu-2 will hopefully have traveled some distance from Chang’e-4, and LRO will be able to spot both on the surface.

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Yutu-2 has rolled out and has begun roving

8:29 am

The new colonial movement: China’s second lunar rover, Yutu-2, has rolled off of the Chang’e-4 lander and begun its roving.

Yutu will rove within Von Kármán craterand analyse the variations of composition of the lunar surface the Visible and Near-Infrared Imaging Spectrometer (VNIS), while also returning unprecedented images with a panchromatic camera.

The rover’s two offer science payloads, the Lunar Penetrating Radar (LPR) and Advanced Small Analyser for Neutrals (ASAN), the latter developed by the Swedish Institute of Space Physics in Kiruna, will provide insight into the lunar subsurface to a potential depths of hundreds of metres and the space environment and interactions with the surface respectively.

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Chang’e-4 successfully lands on far side of Moon

10:24 pm

The new colonial movement: China’s Chang’e-4 lander/rover has successfully landed on far side of Moon.

Early reports of a successful landing sparked confusion after state-run media China Daily and CGTN deleted tweets celebrating the mission. China Daily’s tweet said: ‘“China’s Chang’e 4 landed on the moon’s far side, inaugurating a new chapter in mankind’s lunar exploration history.”

Official confirmation of the landing came two hours later via state broadcaster CCTV, which said the lunar explorer had touched down at 10.26am (2.26am GMT). The Communist party-owned Global Times also said the probe had “successfully made the first-ever soft landing” on the far side of the moon.

No reason has been given for the deletion of the tweets, though I suspect they did so because they were simply premature.

Update: More information here, including images.

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Engineers adjust Chang’e-4’s orbit

7:39 am

The new colonial movement: Engineers have adjusted Chang’e-4’s lunar orbit in preparation for landing.on the Moon’s far side.

The probe has entered an elliptical lunar orbit, with the perilune at about 15 km and the apolune at about 100 km, at 8:55 a.m. Beijing Time, said CNSA.

Since the Chang’e-4 entered the lunar orbit on Dec. 12, the ground control center in Beijing has trimmed the probe’s orbit twice and tested the communication link between the probe and the relay satellite Queqiao, or Magpie Bridge, which is operating in the halo orbit around the second Lagrangian (L2) point of the earth-moon system.

The space engineers also checked the imaging instruments and ranging detectors on the probe to prepare for the landing.

They need to time the landing so that it comes down in the Moon’s early morning. This will not only provide better visuals, with shadows to see surface details, but more importantly will give them 14 Earth days before sunset to get settled on the surface and initiate rover operations.

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A detailed look at Chang’e-4

9:58 am

Link here. Lots of nice information, including the fact that Chang’e-3 seems to still be functioning in a limited manner, and that Chang’e-4 is depending not on solar panels but a radioactive thermal electric system, similar I think to the RPGs that NASA uses on its deep space missions. (I am uncertain however about this, based on looking at the video at the link, which seems to show solar panels on Chang’e-4. They could be instead panels to protect the spacecraft from the sun’s heat.)

They enter lunar orbit on December 12, and will likely land in the first week of January.

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China launches lunar rover/lander Chang’e-4; Saudi satellites

12:09 pm

Using its Long March 3B rocket, China on December 7 successfully launched its Chang’e-4 rover/lander, aimed at being the first probe to land on the Moon’s far side.

It will take the probe five days to reach the Moon and land.

The same day China also launched two Earth observation satellites for Saudi Arabia, using its Long March 2D rocket.

The leaders in the 2018 launch standings:

35 China
20 SpaceX
13 Russia
10 Europe (Arianespace)

China has widened its lead over the U.S. 35 to 32 in the national rankings. China also looks like it is going to come close to meeting its prediction of 40 launches for 2018.

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