China has successfully returned to Earth the first batch of experimental ‘lunar clay bricks’ designed for future construction on the moon.

According to China’s CCTV News, the bricks were brought back to Earth by the Shenzhou-21 spacecraft after spending a year in space. According to Chinese researchers, the bricks are in excellent condition.

According to Xinhua News Agency, the batch is part of a historic experiment conducted on the Chinese space station. The experiment began in November 2024, when the Tianzhou-8 cargo ship delivered simulated lunar soil samples to the space station. A total of 74 small bricks were installed on an exposure platform on the station’s outer surface.

The bricks were made of a material that matches the composition of real regolith (lunar clay) and three types of techniques were used in their production: hot press sintering, electromagnetic induction sintering, and microwave sintering. This increased their pressure-bearing capacity by three times.

China sent these bricks into space primarily to test three key properties: mechanical performance, thermal performance, and radiation resistance.