It’s like something out of a Hollywood blockbuster: an astronaut looks out the window and suddenly notices a thin crack running across the glass, separating him from the deadly vacuum by just a few centimeters. But what happened to the crew of the Chinese Shenzhou-20 mission last November was not a movie, but a harsh reality that nearly led to a catastrophe in orbit.

The Shenzhou-21 spacecraft capsule with the Shenzhou-20 crew at the landing site in the Inner Mongolia Autonomous Region in northern China on November 14, 2025. Source: Xinhua

Commander Chen Dong was the first to notice the danger. What at first appeared to him to be ordinary trash or a leaf stuck to the glass turned out to be much more sinister. A triangular mark was clearly visible on the inner surface of the window — a crack left by a collision with an unknown object.

“I went out to inspect it, and my eye immediately noticed this anomaly,” recalled the commander. In an instant, realization came with a chill of fear: their station had been attacked by a piece of space debris. Scientists still do not know its origin, but they assume that the deadly guest was no larger than a millimeter. This proved sufficient to break through the spacecraft’s strong defenses.

Don’t panic

Despite the dramatic nature of the situation, there was no panic on board. Taikonaut Wang Jie, who was responsible for safety, handled the incident with professional calm. He explained that the design of the porthole was not just simple glass, but a complex engineering system.

“The outer layer is just a protective screen, a kind of ‘shield’. The main pressure is held by two inner sealed layers,” he reassured the audience. For detailed analysis, the astronauts used a special microscope that looked like a pen. They were shocked by what they saw: a network of cracks, some relatively long, others shorter, but the most dangerous thing was that some of them went right through the material.

Rescue operation

Unlike in movies, where everything is decided in seconds, the real drama unfolded over several days. However, the consequences could have been catastrophic. The damaged Shenzhou-20 could no longer be used to return the crew home. The risk of depressurization during descent was too great.

The Chinese flight control center quickly developed a rescue plan. The crew of Shenzhou-20 was forced to abandon their spacecraft and temporarily “move” to the station. They returned home in the Shenzhou-21 capsule, which was originally intended for their replacements. This created a new problem: the new crew was left in orbit without a vehicle.

The situation was saved by the fact that the empty emergency Shenzhou-20 was later successfully undocked and returned to Earth in automatic mode.

Warning for the future

Photos of collisions show how destructive even minor impacts on a spacecraft’s hull can be. Photo: NASA

This incident is not just a story about successfully avoiding disaster. This is a stern warning to all those who are exploring near-Earth space today. Our orbit has turned into a crowded garbage dump, where thousands of objects are hurtling around at breakneck speed.

We will never know what exactly hit Shenzhou-20 — a microscopic fragment of an old rocket or paint from another satellite. But scientists unanimously warn that a chain reaction of collisions (Kessler syndrome) could render space unsuitable for flights for decades.

Earlier, we explained what kind of event could destroy the entire orbital infrastructure in 2.8 days.