posted 12-07-2018 06:15 AM               

Please use this topic to discuss China's Chang'e 4 mission to send a probe and rover to make the first-ever landing on the far side of the moon.

posted 12-07-2018 06:18 AM               

Unfortunately it looks unlikely that China will be providing live coverage of the launch, in which case the first official news after liftoff may only come once the spacecraft have successfully entered lunar transfer orbit.

posted 01-03-2019 03:14 AM               

A Chinese robotic probe carrying a small, multi-wheeled rover has become the first spacecraft in history to land on the far side of the moon.

posted 01-04-2019 09:46 AM               

"What's next for the rover is to take a picture of the front side of the lander, after that, it will go to its planned area and start a series of scientific exploration projects in the Von Karman crater," said Zhang Yuhua, deputy chief commander and designer for the Chang'e-4 lunar mission.

The Jade Rabbit-2 will survey the lunar terrain during the Moon's daytime which lasts until January 12. After that, a 14-day-long Moon night is expected to come.

posted 01-04-2019 01:14 PM               

One of [Chief Designer at the Lavochkin Design Bureau Georgi] Babakin's final dreams had been to recover soil samples from the far side of the Moon. Work on such a project had, in fact, begun in 1970 during his lifetime. The plan consisted of an orbiter and a lander — the former to serve as a communications satellite between the latter and Earth. The mission was evidently scheduled for launch sometime in 1972, but after Babakin's death, the idea gradually fell to the wayside, partially because of the high level of technical complexity.

posted 01-04-2019 08:32 PM            

It's not the only plan that didn't come to fruition until much later. I distinctly remember a TV news report in (probably) the late 1970s telling me how NASA planned to collect a sample from an asteroid and return it to Earth. I thought at the time that the plan seemed over-ambitious. Forty years (or so) later, we are watching as preparations are made for OSIRIS-REx to bring a sample of asteroid Bennu back to Earth.

posted 01-09-2019 07:53 AM            

"What's next for the rover is to take a picture of the front side of the lander...

posted 01-11-2019 09:13 AM               

Real time footage of the Change'e 4 lander's descent to the surface:

posted 01-12-2019 10:16 AM               

Chang'e 4 Lander Coordinates

Chang'e 4 safely set down on the plains of Von Kármán crater last week (3 January 2019). Soon thereafter a color image of the immediate surroundings was relayed back to the Earth from the farside!

Above: Following the Chang'e 4 descent frames (CNSA/CLEP) to the surface makes it easy to find the exact landing spot in a NAC image, which was taken before the landing. Note that the NAC image is rotated so north is down to match the Chang'e 4 frames. NAC M1298916428LR. (NASA/GSFC/Arizona State University)

The prominent crater (about 25 meter diameter) in front of the lander can be seen just below and to the left of the bottom arrow (below).

Above: The Chang'e 4 spacecraft set down between the two arrows at 45.457 degrees South, 177.589 degrees East, plus or minus 20 meters. Full resolution (80 cm pixel scale) NAC image M1298916428LR, acquired on 8 December 2018 (before the landing), note that image is rotated 180 degrees relative to the opening images, north is up. Image width is 880 meters. (NASA/GSFC/Arizona State University)

Explore more of the area around the landing site; same image as above, but more of it (80 cm pixels) here.

posted 01-12-2019 10:21 AM               

Here is where Chang'e-4 landed, on a map of the farside:

And a closeup with crater names:

posted 01-15-2019 09:37 AM               

Chinese media state that the experiment contains six species: cotton, rapeseed, potato, arabidopsis, fruit fly and yeast, with Xinhua reporting that no signs of growth have been found among the species other than cotton.

Xie Gengxin, chief designer of the biological experiment payload for the Chang'e-4 mission, told CCTV that, "There are animal, plants and microorganisms in this payload, creating a micro-ecosystem in a closed environment. We guide the sunlight to the inside of the tin, which is much stronger than that on the Earth. We will study their photosynthesis under strong sunlight and compare it with the experiment on the Earth."

Xie added that the experiment is taking place in the low gravity and high radiation lunar environment.

posted 02-02-2019 11:07 AM               

Here's a new image of the Chang'e 4 lander taken by Yutu 2 rover. One of the three 5-metre booms for the low frequency radio astronomy instrument can be clearly seen rising vertically from the lander.

Looks like the image was taken at the point at which Yutu 2 spent the first lunar night, based on this map of Yutu-2 route relative to the lander. The LFS instrument is also not entirely dissimilar to the low-frequency astronomy NCLE on the Queqiao relay satellite.

posted 02-06-2019 01:02 PM               

First Look: Chang'e 4

On 3 January 2019 the Chinese spacecraft Chang'e 4 safely landed on the floor of Von Kármán crater (186 kilometer diameter, 116 miles). Four weeks later (30 January 2019), as LRO approached the crater from the east, it rolled 70 degrees 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.

Above: Arrows indicate position of Chang'e 4 lander on the floor of Von Kármán crater. The sharp crater behind and to the left of the landing site is 3900 meters across (12,800 feet) and 600 meters (1970 feet) deep. Image was shrunk by more than a factor of ten (full resolutiuon available here). (NASA/GSFC/Arizona State University)

Above: Area around lander enlarged by a factor of two relative to the native pixel scale (see zoomify below), bright speck between two arrows is the lander. The large crater in the center (just right and below arrows) is about 440 meters (1440 feet) across. (NASA/GSFC/Arizona State University)

posted 02-08-2019 04:59 PM               

Chang'e 4 Rover Comes into View

On 30 January LROC acquired a spectacular limb shot centered on the Chang'e 4 landing site, looking across the floor of Von Kármán crater. At the time, LRO was more than 200 kilometers from the landing site so Chang'e 4 was only a few pixels across and the rover was not discernable. The following day LRO was closer to the site and again slewed (59 degrees this time) to capture another view.

This time the small Yutu-2 rover shows up (two pixels) just north of the lander. Also, shadows cast by the lander and rover are now visible.

Above: The Chang'e 4 rover is now visible to LROC! Just beyond the tip of the right arrow is the rover and the lander is to the right of the tip of the left arrow. The image appears blocky because it is enlarged 4x to make it easier to see the two vehicles. North is to the upper right. (NASA/GSFC/Arizona State University)

At some time after the formation of Von Kármán crater, the crater floor was covered by eruptions of basaltic lava, similar to the eruptions in Hawaii last summer. Chang'e 4 will collect compositional measurements of these farside basaltic rocks, and lunar scientists are anxiously awaiting these results. Do volcanic rocks on the farside differ from the basalts collected from the nearside? We will have to wait and see!

A striking aspect of the floor of Von Kármán crater is the number and variety of impact craters. There is a high density of craters because the surface is more than 3 billion years old! During those 3 billion years, so many small craters (<200 meters (660 feet) in diameter) formed that when a new one forms, the total number of craters does not increase. This seemingly counterintuitive situation occurs because each new crater erases, on average, one older crater of comparable size, a state known as "equilibrium" to crater counting geologists. For surfaces this old (in equilibrium), only larger craters (>1000 meters (3280 feet) diameter), which are not in equilibrium, continue to increase in density and can be used to estimate the age of the surface.

Note also all of the small craters that have formed on top of larger ones. Smaller impacts wear down and degrade larger craters over time. You can easily see a wide variety of crater degradation states, ranging from sharp and crisp (new) to highly degraded (old). As result of all of these impacts (small and large), the surface of the Moon consists of a very fine powder known as regolith, in which the Apollo astronauts made their distinct boot prints. Explore the variety of craters across the floor of Von Kármán crater in the full NAC image.

Above: Chang'e 4 lander (near tip of left arrow) and rover (near tip of right arrow) nestled among craters on the floor of Von Kármán crater. Image is 1700 meters (5580 feet) wide across the center. (NASA/GSFC/Arizona State University)

posted 02-15-2019 08:52 AM               

IAU Names Landing Site of Chinese Chang'e-4 Probe on Far Side of Moon

Five sites on the far side of the Moon now have official names, including Chang'e-4's landing site. The names have significance in Chinese culture, reflecting the background of the probe's team.

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.

posted 02-15-2019 09:41 PM               

As many prominent landscape features of the far side were discovered by Soviet space probes, Soviet scientists selected names for them. This caused some controversy, and the International Astronomical Union, leaving many of those names intact, later assumed the role of naming lunar features on this hemisphere.

posted 03-06-2019 12:09 PM               

Yutu-2 awakened for lunar day 3 of the mission at 02:51 UTC on 28 February, with the lander following later the same day at 23:52. A few days later, the rover stood down for its ‘noon nap’ to avoid heating issues from a high solar incidence angle, at 10:25 UTC on March 3. It will resume its activities early on 10 March, before entering a sleep state around 02:00 UTC on 13 March, when the Sun is low in the sky over Von Kármán crater in preparation for the lunar nighttime.

According to a release by the China Lunar Exploration Program (CLEP) on 4 March, Yutu-2 has so far travelled 127 meters, adding 7 meters to the total of 120 meters driven on lunar days 1 (44.185 m) and 2 (75.815 m).

The apparent relatively low distance is believed to be due to Yutu-2 taking time to image nearby rocks and features in the regolith.

posted 03-30-2019 09:56 AM               

The Chang'e-4 lander awoke at 10:14 UTC/6:14 a.m. EDT today (Mar 30). Both lander and Yutu-2 rover are now active for lunar day 4 of the Chang'e-4 mission on the lunar far side.

posted 05-16-2019 11:57 AM               

Yutu-2, the rover partner to the Chang'e-4 lander, used reflected radiation to analyze the minerals within its landing site inside the moon's Von Kármán crater. In doing so, it spotted layers rich in two mineral types that aren't a match for typical lunar crust. The study authors argue that it is likely these mineral patches represent upper mantle material, according to work appearing today in the journal Nature.

If confirmed, mantle rock from the moon would give researchers a game-changing look at our celestial companion's inner workings, perhaps helping to solve long-standing mysteries about the moon's formation and evolution.

posted 08-30-2019 01:24 PM               

On July 28, the Chang'e-4 team was preparing to power Yutu-2 down for its usual midday 'nap' to protect the rover from high temperatures and radiation from the sun high in the sky. A team member checking images from the rover's main camera spotted a small crater that seemed to contain material with a color and luster unlike that of the surrounding lunar surface.

The drive team, excited by the discovery, called in their lunar scientists. Together, the teams decided to postpone Yutu-2's plans to continue west and instead ordered the rover to check out the strange material.

With the help of obstacle-avoidance cameras, Yutu-2 carefully approached the crater and then targeted the unusually colored material and its surroundings. The rover examined both areas with its Visible and Near-Infrared Spectrometer (VNIS), which detects light that is scattered or reflected off materials to reveal their makeup.

So far, mission scientists haven't offered any indication as to the nature of the colored substance and have said only that it is "gel-like" and has an "unusual color." One possible explanation, outside researchers suggested, is that the substance is melt glass created from meteorites striking the surface of the moon.