BEIJING, China — Three Chinese astronauts returned to Earth on Friday after being temporarily stranded at their nation’s space station due to damage sustained by their original spacecraft from space debris. The crew departed in a replacement shuttle designed for a new mission.

The astronauts—Chen Dong, Chen Zhongrui, and Wang Jie—were expected to land safely in a remote area of Inner Mongolia later that day. Their return was initially scheduled for November 5, following the arrival of a new crew. However, a weeklong delay was necessary due to minor cracks observed in the window of their original spacecraft, Shenzhou-20, likely caused by impacts from debris orbiting the Earth.

Space debris, consisting of millions of fragments from past launches and collisions, poses a significant risk to both spacecraft and astronauts. These fragments travel at speeds comparable to bullets, making even small pieces potentially dangerous.

The astronauts’ return flight was aboard the Shenzhou-21 mission, which had recently delivered a new team to the Tiangong space station. The Manned Space Engineering Office confirmed that the original spacecraft would remain in orbit, although it remains unclear how this incident might impact future missions, which are generally carried out every six months.

Despite the unexpected situation, the returning astronauts were reported to be in good health and had been living and working normally during their six-month rotation at the space station. The ongoing commitment to human spaceflight has marked significant advancements in China’s space program since it began in 2003, including successes such as the establishment of the Tiangong space station and plans to land a person on the moon by 2030.

The mission also involved sending four mice to the space station to study the effects of weightlessness on living organisms. This research is a critical step in understanding how space travel impacts various forms of life, potentially paving the way for future human exploration.

As China’s ambitions in space continue to grow, monitoring and addressing risks from space debris will be essential for the safety of future missions and astronauts. The recent incidents highlight the ever-present challenges in maintaining a sustainable presence in Earth’s orbit.