China Launches Chang’e-6 to Collect Samples from Moon’s Far Side

China has officially launched its most complex robotic lunar mission to date. On May 3, 2024, the Chang’e-6 spacecraft lifted off from the Wenchang Space Launch Center in Hainan province, aiming to accomplish a feat no nation has ever achieved. The mission is designed to land on the far side of the moon, collect roughly 2 kilograms of rock and soil, and return those unique samples safely to Earth.

A Historic Launch on the Long March 5

The mission began with the thunderous roar of a Long March 5 Y8 rocket, China’s most powerful launch vehicle. This heavy-lift rocket carried the 8.2-metric-ton spacecraft into orbit, marking the start of a technically demanding 53-day journey.

Unlike previous sample return missions undertaken by the United States, the Soviet Union, and China’s own Chang’e-5 in 2020, this probe is headed for the lunar hemisphere that always faces away from Earth. Specifically, it targets the Apollo crater located within the massive South Pole-Aitken (SPA) basin. This area is of immense scientific interest because it may contain material ejected from deep within the moon’s mantle during ancient impacts.

The Critical Role of Queqiao-2

Landing on the far side of the moon presents a unique engineering challenge: direct communication with Earth is impossible. The mass of the moon blocks all radio signals. To solve this, China launched a dedicated relay satellite named Queqiao-2 earlier in March 2024.

This satellite currently orbits the moon in a specialized path that allows it to maintain a line of sight with both the Chang’e-6 lander on the lunar surface and ground control stations in China. Without Queqiao-2 acting as a data bridge, the lander would be completely cut off from command, making the precise operations required for landing and sampling impossible.

Why the Far Side is Different

Scientists are eager to get their hands on rocks from the far side because of the “lunar dichotomy.” The side of the moon we see from Earth is covered in large, dark plains of cooled lava known as maria. In contrast, the far side is heavily cratered, rugged, and has a much thicker crust with very few maria.

Geologists believe the samples from the South Pole-Aitken basin could answer fundamental questions about the solar system:

  • Age of the Moon: The samples may help confirm the timeline of the “Late Heavy Bombardment,” a period roughly 4 billion years ago when asteroids pummeled the inner solar system.
  • Internal Composition: Because the impact that created the SPA basin was so massive, it likely punched through the crust. The rocks collected here might actually be from the lunar mantle, offering a look at the moon’s interior structure.
  • Planetary Formation: Understanding why the near side and far side are so chemically and geologically different will refine models of how Earth and its moon formed.

International Cooperation on Board

While this is a Chinese National Space Administration (CNSA) mission, the Chang’e-6 lander and orbiter are carrying scientific instruments from four other nations. This highlights a growing trend of international collaboration in China’s space endeavors.

The international payloads include:

  • France (DORN): An instrument designed to detect radon gas and its decay products to study how volatiles transport across the lunar surface.
  • Sweden (NILS): The Negative Ions on Lunar Surface instrument will detect negative ions emitted from the surface due to solar wind interaction.
  • Italy (INRRI): A passive laser retroreflector that will be used for laser ranging and precise positioning.
  • Pakistan (ICUBE-Q): A small cubesat orbiter that separated from the main spacecraft to capture images of the moon and the mission.

The Complex "Grab and Go" Maneuver

The operational phase of the mission is a high-stakes sequence of automated events. Once the lander touches down in the Apollo crater, it has a limited window of time (about 48 hours) to complete its work before the orbital geometry changes.

The collection process involves two methods to ensure a diverse sample:

  1. Drilling: A drill will bore approximately 2 meters (6.5 feet) into the surface to capture stratified layers of soil.
  2. Scooping: A robotic arm will scrape and scoop rocks and dust from the surface.

Once the canister is full, it will be transferred to an ascent vehicle sitting on top of the lander. This ascender will blast off from the moon’s surface, rendezvous with the orbiter circling overhead, and transfer the samples to a return capsule. This capsule is the only part of the spacecraft that will survive the fiery re-entry through Earth’s atmosphere, aiming for a landing in Inner Mongolia in late June 2024.

Looking Ahead to the Lunar Research Station

The Chang’e-6 mission is not an isolated event. It serves as a precursor to China’s broader plans for a permanent presence on the moon. Successful completion of this mission paves the way for Chang’e-7 and Chang’e-8, which are scheduled for launch in 2026 and 2028 respectively.

These future missions are tasked with surveying the lunar south pole for water ice and testing technologies for using local resources (In-Situ Resource Utilization). The ultimate goal is the establishment of the International Lunar Research Station (ILRS) in the 2030s, a project China is leading as a competitor to NASA’s Artemis program. By bringing back the first samples from the far side, China aims to demonstrate the technical maturity required to lead such a massive infrastructure project.

Frequently Asked Questions

Why is it called the “hidden face” or “dark side”? The term “dark side” is a misnomer. The far side gets plenty of sunlight. It is called “hidden” or “far” simply because the moon is tidally locked to Earth, meaning it rotates at the same speed it orbits, keeping one face permanently turned away from us.

How does Chang’e-6 differ from Chang’e-5? Chang’e-5 landed on the near side of the moon (Oceanus Procellarum) in 2020 and returned 1.73 kg of samples. Chang’e-6 utilizes similar hardware but requires a relay satellite for communication and targets the geologically distinct far side.

When will the samples arrive on Earth? The mission is scheduled to last about 53 days from its May 3 launch. This puts the return date for the sample capsule roughly around June 25, 2024.

Who will study the samples? Initially, Chinese scientists will have exclusive access to catalog and analyze the material. However, based on the precedent set by Chang’e-5, the CNSA is expected to open applications for international researchers to study the samples after an initial period of domestic analysis.