Moon Monday #174: Launch of Chang’e 6, the instrumental 7, and claims that are questionable

This week’s Moon Monday is a Chinese lunar program special, covering the incredible Chang’e 6 and 7 missions, with some commentary questioning claims and narratives around some of China’s decisions. At 2600 words, this is likely the longest Moon Monday ever so grab a coffee or beverage of your choice and enjoy an uninterrupted read.

Launch of the Chang’e 6 sample return Moon mission by a Long March 5 rocket. The launch attracted hundreds of thousands of excited spectators at and around the coastal Wenchang Space Launch Center. Image: CNSA / Xinhua

On Chang’e 6 and its rich sampling site

On May 3 at 9:30 UTC, a Chinese Long March 5 rocket launched Chang’e 6, the world’s first spacecraft designed to fetch samples from the Moon’s farside. About 37 minutes after liftoff, the 8200-kilogram Chang’e 6 spacecraft stack separated from the rocket, entering—per CNSA—its planned orbit of 200 by 380,000 kilometers.

Chang’e 6’s complex 53-day mission involves orchestrating four spacecraft: an orbiter, a lander, an ascender, and a reentry capsule (returner). The combined stack will reach Luna on May 7, and attempt entering into its orbit by firing the orbiter’s engines. At some unspecified point the Chang’e 6 lander, carrying atop it the ascender, will separate from the orbiter. In early June, the lander will attempt a soft touchdown within the 3.98-billion-year old, 500-kilometer wide Apollo impact crater on the Moon’s farside, specifically in one of the three candidate regions near Apollo’s southern rim each of which differ in their ages and geology.

The Chang’e 6 lander’s instrument suite—comprising cameras, a ground penetrating radar, and a mineral spectrometer—will provide the context necessary to identify the best spots to drill and scoop samples from. As Andrew Jones reports, the lander hosts a surprise mini-rover carrying an infrared spectrometer which might help. After the lander collects up to two kilograms of lunar farside material and loads them into the ascent vehicle, the latter will launch itself into lunar orbit and carefully dock with the orbiter. The samples will then be transferred to the reentry capsule. After the ascender is jettisoned, the orbiter will return towards Earth on June 25 and release the capsule, which will perform a bounced atmospheric reentry to hopefully safely descend and land in China’s northern Inner Mongolia Autonomous Region.

Chang’e 6 mission profile (with an edit to correct the landing date). Graphic: SCMP

The Chang’e 6 lunar samples will be scientifically even more valuable than the Chang’e 5 samples. Since the Apollo crater is embedded in the Moon’s largest, deepest, and oldest crater, the 2500-kilometer-wide South Pole-Aitken (SPA) basin, the diversity of materials within Chang’e 6 samples could help scientists worldwide solve a whole host of Moon mysteries—from explaining why the lunar farside is so enigmatically distinct to the familiar nearside, which is necessary to understand not just Luna’s evolution but that of our Solar System, to better understanding our Moon’s origin. Since the three Chang’e 6 landing regions along the Apollo crater’s southern rim have different ages and geological features, the Chang’e 6 samples would help solve differing extents of these Moon mysteries—depending on where Chang’e 6 decides to land, a decision CNSA will take before descent based on engineering and operational constraints.

Top left: The Chang’e 6 landing zone (red box) in the Apollo crater within the South Pole-Aitken basin (black circle); Bottom left: The three Chang’e 6 candidate landing regions (colored lines); also marked with a white cross is the Chang’e 4 landing site; Right: Zoomed in view of the three candidate landing regions lying along the southern rim of the Apollo crater. Images: Xingguo Zeng, Wei Zuo, et al.

Is China landing Chang’e 6 in the Apollo crater to signal the US of a race?

Forbes published an article by Greg Autry that implies the same:

There is a serious race to the Moon in a quest for mineral resources and China is sending us a message with this mission. Chang’e 6 will land in the resource-rich South Pole-Aitken (SPA) basin. Specifically, China is targeting a crater called “Apollo” which is named in honor of America’s great lunar achievement. Apollo’s interior and adjacent craters are named for Apollo astronauts and memorialize deceased NASA employees including the lost crew of the Space Shuttle Columbia. Chang’e 6 will literally raise a communist Chinese flag there. The Chinese are extremely careful with protocol, any small slight is intentional.

Imagine being so deep in your own narrative that you find even the name of the region hosting a mission’s landing site to be an intentional declaration of a race and active hostility. Yes, China has its own political gains from choosing to go to the Moon’s farside a second time with another unique mission but as far as the landing site itself is concerned, reading the Chang’e 6 landing site paper and its related trail firmly reveals its selection to be a purely engineering and scientific process based on operational abilities and constraints. Maybe, just maybe, every single space decision of China—or that of any other country—doesn’t orbit the US.

More importantly, recall that late last year NASA secured a remarkable exception from the US Congress for the country’s researchers to be able to apply to access and study China-brought Chang’e 5 samples. This is the sort of bridge that doesn’t get built in a day. But weaponizing even the most mundane, emergent aspects of a complex mission is the kind of aggressive propaganda that further fuels distrust and impedes global scientific progress. Thankfully, so far it seems like the policy of international (and US) access to Chang’e 5 lunar samples will extend to Chang’e 6.

International instruments onboard

The Chang’e 6 spacecraft stack, with the lander and orbiter prominently visible. Image: CNSA

The Chang’e 6 mission also carries various international payloads. Its orbiter will deploy Pakistan’s 7-kilogram CubeSat called ICUBE-Q, making it the country’s first Moon mission. Developed by Pakistan’s Institute of Space Technology (IST) with aid from China, ICUBE-Q hosts two optical cameras and a magnetometer, and hopes to detect potential signs of water ice on the Moon’s poles.

The Chang’e 6 lander carries three instruments from Europe:

  1. The French space agency’s DORN instrument will measure the noble gas radon leaking out of the Moon’s surface, which would be independent evidence that our Moon and Earth do indeed have a common origin. DORN will also study volatile gases such as water vapor in the Moon’s exosphere.
  2. Italy-based SCF Lab’s INRRI retroreflector will reflect laser pulses from lunar orbiters to make precise distance measurements and aid their navigation.
  3. NILS, an instrument from the Swedish Institute for Space Physics, will detect highly energetic neutral solar wind atoms slamming and getting reflected from the Moon’s surface. This will help scientists study surface elements as well as local magnetic fields.

Many thanks to Open Lunar Foundation, Kris Zacny of Honeybee Robotics, and Gordon Roesler  for sponsoring this week’s Moon Monday. If you love this community resource too, please join them and support my work.

Cue Queqiao 2

Since Chang’e 6’s surface mission will on the Moon’s farside, the side we can’t see from Earth, mission operators will command the lander and receive data from it via the recently launched Queqiao 2 relay orbiter, which China successfully tested in April. Queqiao 2 will also relay communications for China’s upcoming Change’e 7 (more on that below) and Chang’e 8 landers, currently targeting launch in 2026 and 2028 respectively. The Queqiao 2 mission is testing and verifying technologies that will feed into the upcoming Queqiao satellite constellation, the world’d first lunar navigation & communications service. The Queqiao constellation could also provide communications support for China’s first crewed Moon landing, currently targeting a launch by 2030.

The instrumental and increasingly international 7

Illustration of the Chang’e 7 lander and orbiter. Image: CMG

CNSA is targeting launching the Chang’e 7 lander and orbiter in 2026. The lander, after touching down in one of the key identified landing regions on the Moon’s south pole, will deploy a rover and one or two hoppers. Similar to the NASA VIPER and JAXA-ISRO LUPEX missions, one of the Chang’e 7 elements will use a drill to sample materials in nearby permanently shadowed areas from varying depths. These will be fed into a heating furnace for the onboard Lunar Water Molecular Analyzer (LWMA) to detect water ice and other volatile resources like ammonia.

Chang’e 7 will also carry a ground-penetrating radar to map the local subsurface, make local magnetic field measurements, and carry spectrometers to measure the composition of the local lunar material. In similar vein to the seismometers selected to fly to the Moon on the NASA-funded Draper-led CLPS mission and Artemis III, Chang’e 7 will have one to help scientists better understand the lunar interior and also constrain the rate of seismic activity and amount of micrometeorite impacts on the lunar south pole, which will help safely plan lengthier crewed missions to the region in the future.

Moreover, on April 24, CNSA announced that Chang’e 7 will carry six international scientific instruments. The orbiter will carry a hyperspectral mineral mapping camera made by Egypt and Bahrain, a three-kilogram instrument duo from Thailand to study solar storms and cosmic rays respectively, and a Swiss-aided radiation monitor to measure incoming and outgoing radiation to and from Earth. For Egypt, Bahrain, and Thailand, this mission represents their first study of Luna. On the other hand, the lander will carry a Russian lunar dust & plasma analyzer, a telescope from the International Lunar Observatory Association, and another retroreflector from Italy-based SCF Lab just like Chang’e 6.

The Chang’e 7 lander was supposed to carry UAE’s second lunar rover too but the partnership was apparently blocked by US export control rules.

Also see: A tale of lunar collaboration between JAXA and ISRO

Did China choose the same lunar landing sites as the US? Or is it the other way round?

Some of the Chang’e 7 candidate landing sites on the Moon’s south pole. Image: DSEL

Western media has tended to cover the Chang’e 7 candidate landing site near Shackleton crater as being “the same” as what NASA desires for the Artemis III crewed Moon landing mission. In fact, Gizmodo titled it “China Oversteps NASA in Choosing Coveted Shackleton Crater for Its Moon Lander”. So, did China really choose the same lunar landing sites as the US? Well, such framing is easily questionable:

  • Firstly, it was always likely, and known, that the robotic Chang’e 7 would land on the Moon’s south pole before the crewed Artemis III does. So can we even call the former to be choosing “the same site” as the latter?
  • Artemis III has 13 candidate landing zones at the moment, which is not exactly a “selection”.
  • More importantly, Shackleton is a big 21-kilometer wide crater, and the number of mission-favorable areas on the rim and nearby ridges are relatively plenty. Even if both missions ultimately chose Shackleton as the main landing region, they may be reasonably far away not just in time but in space too.

While, yes, the water-hosting lunar south pole not being a massive place could eventually mean potential contest between countries—and companies—for some common sites but much before that comes the fact that there are purely engineering and scientific factors that make landing site selections converge to some locations. For example, the Sun perpetually circling the lunar polar horizon coupled with rocky terrain automatically render higher altitude areas desirable power-wise for touchdown—which is what most lunar polar missions end up converging to. I highlighted this point in an invited Media Roundtable discussion hosted by the Duke University recently:

It’s important to keep in mind that not all decisions are taken with the geopolitical adversary in mind. Some of them are purely engineering. But this you would only understand if you have scientists and engineers talking to policy makers. The narrative can cause issues to scale up, and then convert into a lot of unfriendliness that could be impact everyone badly…As journalists, our job is to simplify and clarify the layers of what scientists and engineers do, as well as the geopolitical and policy elements.

Scientists and engineers on both sides of the pond understand these technical factors but they aren’t the only ones in the space chain. Such factors should be considered first before jumping the gun with policy recommendations and changes that are based on shallow narratives. Again, these could also adversely affect international cooperation and collaboration. Ultimately, alarmist propaganda also makes discussing the real challenges more difficult.

Orion’s heat shield took a deeper beating than thought

The Artemis I Orion spacecraft lost big chunks of its heat shield material in several places, and some of its separation bolts melted and eroded. Image: NASA / OIG

A critical new public report by NASA’s Office of Inspector General (OIG) finally reveals to the US taxpayers, with pictures, that the heat shield of the Artemis I Orion spacecraft did in fact incur more damage than the agency let on a few months after the mission, then deeming it to be a non-blocker for the crew-carrying Artemis II launch. Several places on the heat shield lost big chunks instead of melting away. Even though the crew module ended up being safe, debris from these chunks could’ve damaged Orion’s parachutes, thus potentially threatening lives of future astronauts riding the capsule. Moreover, three out of four “separation bolts” on the shield substantially melted and eroded, allowing some heat to reach the crew module. More such hot gas entering the vehicle could risk lives. Jeff Foust reports that for Artemis II, NASA will install additional thermal protection material in the bolt gaps to circumvent this issue.

Understanding exactly why the heat shield didn’t work perfectly as designed is thus a primary blocker for Artemis II because there’s no other way to test it at a relevant scale. Recall that NASA already installed the Artemis II Orion’s heat shield in June 2023.

More Moon

  • As part of the pre-launch testing of the Artemis II Orion spacecraft stack, which will carry four astronauts around the Moon and back no earlier than September 2025, engineers completed checking that Orion’s electromagnetic emissions don’t cause interference with the spacecraft itself, or more specifically, with the functioning of its various components.
  • Ling Xin reports that by synthesizing data from CNSA’s Chang’e 1–4 missions, NASA’s LRO and twin GRAIL orbiters, and ISRO’s Chandrayaan 1 orbiter, China has made the highest resolution geological map of our Moon yet. The map, which took more than 100 researchers over a decade to compile, is free to use for non-commercial purposes, including lunar geology research and science communications. China itself is using the maps to support its growing lunar ambitions. The team is also working on furthering the map’s resolution, including making high-accuracy, derived regional maps suitable for advanced mission planning.
Image: Chinese Academy of Sciences / Xinhua
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