A pair of taikonauts ventured outside China’s Tiangong space station this week to take a closer look at the cracked viewport window of the Shenzhou-20 vehicle.

The two worked for approximately eight hours, assisted by the station’s robot arm. In addition to tasks that included the installation of a debris protection device for the orbital outpost, Wu Fei and Zhang Lu also inspected the damaged Shenzhou window.

The Shenzhou-20 vehicle remains attached to the Tiangong space station after it was deemed unsafe for transporting its three-person crew back to Earth. A crack in the vehicle’s window was spotted shortly before it was due to depart.

Managers reckon that the crack was caused by a tiny piece of space debris and opted to send the Shenzhou-20 crew home in the Shenzhou-21 capsule. The launch of Shenzhou-22 was brought forward, and the vehicle is expected to return the Shenzhou-21 crew to Earth in 2026.

While there is still no return date for the Shenzhou-20 capsule, managers will be able to use the inspection results to decide what, if any, repairs are required before the uncrewed capsule returns to Earth. Getting a look at the exterior of the affected portion of the spacecraft before it is subjected to re-entry forces should provide invaluable data.

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The spacewalk was also an opportunity to try out a pair of new spacesuits, which were delivered on July 15 by the Tianzhou-9 freighter. The previous generation was good for 15 extravehicular activities (EVAs) over three years. The operational lifespan of the new units has been upped to 20 EVAs over four years, according to the China Astronaut Research and Training Center.

The damage to Shenzhou-20 has served to highlight two uncomfortable spaceflight truths. The first is that, despite calls for SpaceX and Elon Musk to mount a rescue, retrieving stranded spacefarers is a challenge, and international agreements and interoperability between spacecraft are needed before any rescue mission can be attempted.

The second is the problem of debris itself. In 2022, a micrometeoroid punched a hole in the coolant system of Soyuz MS-22, rendering the craft unsafe for human use. A few months later, in 2023, a Progress cargo freighter also sprang a coolant leak. At orbital speeds (approximately 17,500 mph), even the tiniest micrometeoroid or piece of debris can pose a serious hazard to spacecraft. ®