Tag Archives: Chang’e 4

Planetary rover update: January 22, 2019

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!
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Update on Chang’e-4 plant experiments

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

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

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!

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.
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Using LRO to find Chang’e-4

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

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

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

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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Chang’e-4 establishes link with Queqiao relay satellite

The new colonial movement: Chang’e-4 has successfully established a communications link with its Queqiao relay satellite.

This success puts China one step closer to its January attempt to soft land Chang’e-4’s lander on the far side of the Moon. Once on the surface, Chang’e-4 must be able to communicate with Queqiao in order to relay data to Earth.

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A detailed look at Chang’e-4

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

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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An update on China’s Chang’e-4 lunar lander

Link here. Chang’e-4 is set to land on the far side of the Moon, sometime in December. The article provides some additional details, including information about the likely landing site in Von Kármán crater. It also notes that there are three launches planned at the spaceport prior to the December launch, and that any issue on any of those launches could delay Chang’e-4’s lift-off. .

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China unveils next lunar rover

The new colonial movement: In unveiling its next lunar rover, China today also announced they will hold a contest to name it.

Images displayed at Wednesday’s press conference showed the rover was a rectangular box with two foldable solar panels and six wheels. It is 1.5 meters long, 1 meter wide and 1.1 meters high.

Wu Weiren, the chief designer of China’s lunar probe program, said the Chang’e-4 rover largely kept the shape and conditions of its predecessor, Yutu (Jade Rabbit), China’s first lunar rover for the Chang’e-3 lunar probe in 2013. However, it also has adaptable parts and an adjustable payload configuration to deal with the complex terrain on the far side of the moon, the demand of relay communication, and the actual needs of the scientific objectives, according to space scientists.

Like Yutu, the rover will be equipped with four scientific payloads, including a panoramic camera, infrared imaging spectrometer and radar measurement devices, to obtain images of moon’s surface and detect lunar soil and structure.

The Chang’e-4 lunar probe will land on the Aitken Basin of the lunar south pole region on the far side of the moon, which is a hot spot for scientific and space exploration. Direct communication with the far side of the moon, however, is not possible, which is one of the many challenges for the Chang’e-4 lunar probe mission. China launched a relay satellite, named Queqiao, in May, to set up a communication link between the Earth and Chang’e-4 lunar probe.

I am not sure what they mean by “adaptable parts and an adjustable payload configuration.” That sounds like they upgraded this rover’s design to allow them to use it to build many similar rovers for use elsewhere, not just on the Moon. This sounds good, but the conditions on other planets are so different I’m not sure a direct transfer of the rover will work very well.

Chang’e-4’s launch is presently scheduled for December.

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Chang’e-4 launch set for December

China has now scheduled the launch of its Chang’e-4 lunar rover/lander, aimed for the first landing on the Moon’s far side, for sometime this coming December.

They will use China’s Long March 3B rocket, not the bigger Long March 5. As is usual for China, many details about the mission remain secret. The exact landing area has not been announced, other than somewhere in the very large South Pole/Aitken Basin area. The exact date has not been announced, other than sometime in December.

Their planned sample return mission, Chang’e-5, is now set for launch in 2019, “should the Long March 5 rocket be proven ready for flight later this year.”

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Chinese cubesat using Saudi Arabian camera sends back first pictures

A Chinese cubesat, launched as a secondary payload with China’s lunar communications satellite for its upcoming Chang’e-4 mission, used a Saudi Arabian camera to successfully send back its first images this week.

Two of the three images show the Earth rising above the lunar horizon. The third looks down at the Moon’s cratered surface.

These images I think are the first interplanetary images ever taken and successfully transmitted to Earth by a interplantary cubesat mission. Both China and Saudi Arabia should be lauded for the success. It proves that cubesats have the potential to do everything that fullsize satellites do, at much lower cost, and therefore marks the beginning of a revolution in unmanned planetary spacecraft design.

In related news, that lunar communications satellite has now officially reached its Lagrande point.

The satellite, named Queqiao (Magpie Bridge) and launched on May 21, entered the Halo orbit around the second Lagrangian (L2) point of the Earth-Moon system, about 65,000 km from the Moon, at 11:06 a.m. Thursday after a journey of more than 20 days. “The satellite is the world’s first communication satellite operating in that orbit, and will lay the foundation for the Chang’e-4, which is expected to become the world’s first soft-landing, roving probe on the far side of the Moon,” said Zhang Hongtai, president of the China Academy of Space Technology (CAST).

The concept of the Halo orbit around the Earth-Moon L2 point was first put forward by international space experts in 1950s.

While in orbit, the relay satellite can see both the Earth and the far side of the Moon. The satellite can stay in the Halo orbit for a long time due to its relatively low use of fuel, since the Earth’s and Moon’s gravity balances the orbital motion of the satellite.

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China loses contact with one of two lunar cubesats

China has lost contact with one of the two test cubesats that were launched to the moon with their Queqiao Chang’e-4 communications satellite.

Though they continue to receive telemetry from one cubesat, without the second they will be unable to do the radio astronomy and interferometry experiments planned.

The interferometry experiments would have seen the observations made simultaneously by the DSLWP/Longjiang microsatellites to be combined. The test would be verification of technology for a constellation of small, low-frequency radio astronomy satellites that would emulate a telescope with a size equal to the maximum separation between the satellites.

The Chang’e-4 mission could however see some interferometry tests carried out, with Queqiao carrying the Netherlands-China Low-frequency Explorer (NCLE) astronomy instrument, and a Low Frequency Spectrometer (LFS) on the Chang’e-4 lander, which is expected to launch in November or December, following testing of Queqiao.

All is not lost. The cubesat that still functions has a camera, built in Saudi Arabia, and if it takes and successfully transmits any pictures this will be a cubesat landmark, the first interplanetary images ever taken by a cubesat.

Meanwhile, Queqiao Change’-4 is working as expected, laying the ground work for the launch of the Chang’e-4 lander later this year.

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China, the Moon, and the Outer Space Treaty

Link here. The article speaks to the problems of sovereignty, ownership, and political borders created by the language of Outer Space Treaty, specifically illustrated now by China’s newest effort to put a lander on the far side of the Moon.

[This] pioneering space travel has raised concern that China is also interested in the tiny spots on the moon that never go dark, the polar peaks of eternal light. Those peaks are vanishingly small, occupying one-one hundred billionth of the lunar surface − roughly equivalent to three sheets of NHL ice on Earth. But their near-ceaseless sunshine gives them great value as a source of solar energy, to power everything from scientific experiments to mining operations.

Their small size could also, scientists have argued, allow one country to take sole occupancy of this unique real estate without falling afoul of the Outer Space Treaty. That agreement stipulates that no state can exert sovereignty in outer space. But it also calls on countries “to avoid interference” with equipment installed by others.

That provides a loophole of sorts, researchers say. The installation of very sensitive equipment on the peaks of eternal light, such as a radio telescope − a 100-metre long uncovered wire used to study transmissions from the sun, and deeper corners of the universe − could use up much of the available space while also providing a rationale to bar others from the area on the grounds that the telescope is too sensitive to be disturbed.

“Effectively a single wire could co-opt one of the most valuable pieces of territory on the moon into something approaching real estate, giving the occupant a good deal of leverage even if their primary objective was not scientific inquiry,” researchers from Harvard University, King’s College London and Georg-August Universitat Gottingen wrote in a 2015 paper.

Because the Outer Space Treaty outlaws any nation from claiming territory, it provides no method for any nation, or private company, to establish its borders or property rights. To protect what they own nations are therefore will be forced to create their own rules, willy-nilly, such as the one speculated above. And when they disagree, only the use of force will be available to either defend or defy these arbitrary rules.

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China launches communications relay satellite for upcoming lunar mission

China successfully launched a satellite in the early hours this morning designed to relay communications between the Earth and an upcoming lunar lander aimed for the Moon’s far side.

The landing site for this mission is expected to be the Von Kármán crater in the South Pole-Aitken Basin. If successful, this will be the first spacecraft to land on the far side of the Moon.

As such, a communication relay will be required to communicate with Earth. Queqiao [the communication satellite’s name] will provide that role. Launched to an eventual L2 Halo Orbit (Earth-Moon L2 Lagrange Point), the satellite will have a lifetime of five years, covering both this and potentially another Chang’e mission.

The spacecraft is based on the CAST100 small satellite platform, with commonality to the often used DFHSat system that finds its way on to a number of Chinese spacecraft. It has a mass of 425kg and uses a hydrazine propulsion system. It will transmit telemetry back to Earth via its S-band antenna, while X-band data will provide the communication path between the lander and rover.

This Chinese lander could also be the first to confirm the existence of water ice on the lunar surface.

With this launch China once again ties the U.S. in launches for 2018. The leaders:

15 China
9 SpaceX
5 Russia
5 ULA

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China to attempt to grow potatoes on Moon

China’s Chang’e-4 lunar rover/lander, set to launch in 2018, will include a small experiment that will attempt to grow potatoes from seeds.

Note that I have just realized that I have been confusing Chang’e-5 with Chang’e-4. Chang’e-5 is a sample return mission that they hope to launch this year. It does not include a rover. Chang’e-4 is a lander/rover mission that is planned for 2018.

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Sweden delivers science instrument for Chinese lunar probe

The new colonial movement: The Swedish Institute of Physics has completed construction and delivered a science instrument to be flown on China’s Chang’e 4 spacecraft that will bring an orbiter, lander, and rover to the Moon’s far side in 2018.

The instrument will be installed on the rover, and will study the surface and how it interacts with the solar wind. This will also be a continuation of research performed by India’s Chandayaan-1 orbiter.

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Next China lunar lander aimed for farside south pole

The competition heats up: China announced plans today to send its next lunar lander, Chang’e 4, to the Moon’s farside south pole in 2018.

The lander of Chang’e-4 will be equipped with descent and terrain cameras, and the rover will be equipped with a panoramic camera, he said. Like China’s first lunar rover Yutu, or Jade Rabbit, carried by Chang’e-3, the rover of Chang’e-4 will carry subsurface penetrating radar to detect the near surface structure of the moon, and an infrared spectrometer to analyze the chemical composition of lunar samples.

But unlike Chang’e-3, the new lander will be equipped with an important scientific payload especially designed for the far side of the moon: a low-frequency radio spectrometer. “Since the far side of the moon is shielded from electromagnetic interference from the Earth, it’s an ideal place to research the space environment and solar bursts, and the probe can ‘listen’ to the deeper reaches of the cosmos,” Liu said.

The U.S. had been in the lead in the land rush to gain dominance in the possibly water-rich lunar south pole. We apparently have lost this lead with decision of President Obama and Congress to focus elsewhere, either the asteroids or Mars.

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China outlines the plans for its next two unmanned lunar probes, with the second targeted as a 2017 sample return mission.

China outlines its plans for its next two unmanned lunar probes, with the second targeted as a 2017 sample return mission.

Key quote:

The new mission planned for 2017 would mark the third and final phase of China’s robotic lunar exploration program and pave the way for possibly landing an astronaut on the moon after 2020.

As I mentioned last night, the soft landing on Saturday demonstrated they are developing the technology to land a manned vehicle safely on the Moon. To return samples safely would demonstrate they are developing the technology to return that manned vehicle safely as well.

Update: Yutu did not land anywhere near its planned landing location.

China had originally publicized a location in the Sinus Iridum (Bay of Rainbows) — a level area thoroughly surveyed by a previous Chinese mission — as the landing spot. Local media even stated that Chang’e 3 landed there. But Chinese scientists have since confirmed that the spacecraft landed slightly to the east, in the northern part of Mare Imbrium (Sea of Rains).

It is unclear whether this was a late change or the result of a technical problem.

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