China has completed multiple batches of in-orbit experiments on material and biological samples using its space station's extravehicular exposure platform, achieving a number of original results, according to Pang Zhihao, a chief science communication expert on space exploration technology.

The space station is currently carrying out its fourth round of extravehicular exposure experiments, covering eight scientific projects and 26 sample units, with exposure periods of one to two years.

"Extravehicular exposure experiments place material and biological samples on platforms outside the space station, exposing them directly to the real space environment," said Pang in an interview with Science and Technology Daily.

The samples are subjected to high vacuum, atomic oxygen erosion, cosmic radiation, sharp temperature fluctuations and micrometeoroid impacts. After a period of in-orbit testing, they are retrieved by astronauts or a robotic arm and returned to Earth for analysis, Pang revealed.

According to the expert, in materials research, China has completed the world's first in-orbit verification of the space stability of a stainless magnesium alloy, confirming its advantages of being both lightweight and radiation-resistant. It also conducted solid-liquid composite lubrication and gel lubrication friction tests outside the station, achieving near-zero wear.

Meanwhile, simulated lunar soil bricks remained intact after one year of exposure to extreme space conditions, verifying the feasibility of using such materials for lunar surface construction, Pang said.

In the field of biology, China conducted extravehicular exposure experiments on extremophile microorganisms and nematodes, and data on radiation damage and life tolerance were obtained, providing a basis for the exploration of extraterrestrial life and the assessment of radiation risks to astronauts.

"The platform has completed multiple batches of sample retrieval and established an evaluation system for space service of materials, providing key data for material selection and protection design for crewed lunar missions and deep-space exploration," Pang noted.

He added that many results can also be applied to high-end ground equipment, such as components for aviation, nuclear power and precision transmission, thus improving corrosion, wear and radiation resistance.

China's space station, Tiangong, which means Heavenly Palace, has now entered an era of long-term human habitation. The Shenzhou-23 spacecraft was launched on May 24 this year, meaning its crew has now been in orbit for over five months. One crew member is scheduled to conduct a one-year in-orbit stay, while the country's 2030 crewed moon landing mission is advancing steadily.