Planetary science: Reconstructing Chang’E-4’s landing

The precise location of the landing site of Chang’E-4 and a reconstruction of its descent to the lunar surface are presented in Nature Communications this week.

On 3rd January 2019, the Chinese Chang’E-4 spacecraft successfully landed in the Von Karman crater on the lunar farside. With no Earth-based radio tracking and telemetry data, the landing process took place under autonomous control.

Chunlai Li and colleagues reconstructed the landing trajectory of Chang’E-4 using images from the spacecraft’s landing camera, which were transmitted back to earth via the Queqiao satellite after landing. Using images from the camera and the Yutu-2 rover, the authors show that Chang’E-4 landed on the gentle slope of a degraded crater near the rim of 25 m crater to the north, and was surrounded by five craters. They then used images obtained from the separate navigation camera to determine a precise landing site of 177.5991°E, 45.4446°S with an elevation of -5,935 m.

The research could serve as a basis for future autonomous spacecraft landings across the Solar System (for example, on the surface of asteroids).