China’s Chang'e-6 Moon Mission Launch

On May 3, 2024, China successfully launched the Chang’e-6 robotic probe, marking the beginning of a historic 53-day mission. This complex endeavor aims to retrieve rock and soil samples from the far side of the moon for the first time in human history. If successful, the material brought back will provide scientists with critical data regarding the formation of the moon and the early history of the solar system.

The Launch Details

The mission began at the Wenchang Space Launch Center located on the coast of China’s southern island province of Hainan. A Long March-5 Y8 rocket, currently China’s most powerful launch vehicle, lifted off at 5:27 p.m. Beijing time. Despite rainy weather conditions at the launch site, the rocket executed a precise ascent.

Approximately 37 minutes after liftoff, the Chang’e-6 spacecraft separated from the rocket and successfully entered the Earth-moon transfer orbit. This trajectory sends the 8.35-metric ton spacecraft on a five-day journey toward the moon, where it will perform a braking maneuver to enter lunar orbit.

Destination: The Apollo Basin

The primary target for this mission is technically challenging. The lander attempts to touch down in the Apollo basin, which is located within the South Pole-Aitken (SPA) basin on the moon’s far side. The SPA basin is a massive impact crater roughly 2,500 kilometers in diameter and is believed to be the oldest and largest impact structure on the moon.

Scientists are specifically interested in this region because the moon’s far side is geologically distinct from the near side. The side facing Earth is covered in large, dark plains of cooled lava known as maria. The far side, however, has a much thicker crust and is heavily cratered. By landing in the deep SPA basin, researchers hope the probe can access material ejected from deep within the lunar mantle, offering clues about the moon’s internal structure that near-side samples cannot provide.

Solving the Communication Problem

Landing on the far side of the moon presents a major hurdle: there is no direct line of sight to Earth. The body of the moon blocks all radio signals, making direct control impossible. To solve this, China launched the Queqiao-2 relay satellite in March 2024, weeks ahead of the Chang’e-6 mission.

Queqiao-2 is now orbiting the moon in a highly elliptical frozen orbit. It acts as a communication bridge, receiving signals from the Chang’e-6 lander and bouncing them back to ground stations in China. This relay link is vital for the automated landing sequence and the sampling process.

The Sampling Process and Return Journey

The Chang’e-6 mission profile is highly complex and involves four distinct components: an orbiter, a lander, an ascender, and a re-entry module. The process is expected to follow this timeline:

  • Orbit and Descent: After reaching lunar orbit, the lander and ascender will separate from the orbiter and descend to the surface.
  • Collection: Once landed, the probe has a tight window of about 48 hours to collect samples. It will use a drill to extract subsurface soil and a robotic arm to scoop rocks from the surface. The goal is to collect approximately 2,000 grams (2 kilograms) of material.
  • Ascent: This is one of the most technically difficult steps. The ascender vehicle must launch from the top of the lander, blast off from the lunar surface, and enter lunar orbit.
  • Docking: The ascender must then autonomously locate and dock with the orbiter waiting above.
  • Transfer: The samples will be transferred into the re-entry capsule.
  • Return: The orbiter will travel back to Earth, releasing the re-entry capsule to land in the Inner Mongolia Autonomous Region of China around late June 2024.

International Scientific Payloads

While this is a Chinese National Space Administration (CNSA) mission, the Chang’e-6 lander carries scientific instruments from international partners. This collaboration highlights the growing global interest in lunar exploration. The payload includes:

  • France: The DORN (Detection of Outgassing RadoN) instrument, which will study the transport of lunar dust and the lunar exosphere.
  • Italy: A laser retro-reflector (INRRI) to accurately measure distances and positioning.
  • ESA/Sweden: The NILS (Negative Ions at the Lunar Surface) payload, developed by the European Space Agency and Sweden, to detect negative ions emitted from the surface.
  • Pakistan: The ICUBE-Q cube satellite, which separated from the orbiter shortly after launch to capture images of the moon and collect magnetic field data.

Why Far Side Samples Matter

The scientific community is eager to analyze these samples because they could resolve a mystery known as the “lunar dichotomy.” The near side and far side of the moon look and act very differently. The near side is rich in potassium, rare earth elements, and phosphorus (KREEP), which are associated with volcanic activity.

The far side lacks these elements and has a much thicker crust. By comparing the Chang’e-6 samples with the near-side samples returned by the Chang’e-5 mission in 2020 and the American Apollo missions of the 1960s and 70s, scientists hope to understand why the moon developed so asymmetrically. This data could also refine the estimated age of the SPA basin, which serves as a benchmark for dating impact craters across the entire inner solar system.

Frequently Asked Questions

Has any country returned samples from the far side of the moon before? No. While the United States (Apollo) and the Soviet Union (Luna) returned samples from the near side, and China’s Chang’e-5 returned near-side samples in 2020, no mission has ever returned material from the far side. Chang’e-6 is the first attempt to do so.

How long will the mission take? The entire mission, from the May 3 launch to the return of the capsule to Earth, is scheduled to last approximately 53 days. This is significantly longer than the 23-day duration of the Chang’e-5 mission due to the complex orbital maneuvers required for the far side.

What rocket was used for the launch? The mission utilized the Long March-5 Y8 rocket. The Long March-5 is a heavy-lift launch vehicle capable of carrying up to 25 tons to low Earth orbit or 14 tons to geostationary transfer orbit. It is the workhorse for China’s most ambitious space projects, including their space station and Mars missions.

Why is it called the “dark side” of the moon? The term “dark side” is a misnomer. The far side gets just as much sunlight as the near side. It is called the “far side” because it always faces away from Earth due to tidal locking (the moon rotates at the same speed it orbits Earth). It is only “dark” in the sense that it is radio-dark to direct communication from Earth.