Chinese astronauts on the Shenzhou 21 mission conducted an eight-hour spacewalk outside the Tiangong space station on December 9 to inspect and maintain equipment.

During the EVA, they photographed cracks in the Shenzhou 20 capsule’s windows, installed a space debris protection system, and replaced the cover of a temperature control adapter.

The damage to Shenzhou 20 was caused by a space junk strike, making it unsafe for its crew to return to Earth.

As a result, the Shenzhou 20 crew returned aboard Shenzhou 21, and Shenzhou 22 was launched uncrewed to provide a future safe return, Space.com has reported.

The spacewalk provided astronauts and officials with a close-up assessment of the capsule’s condition, aiding plans to eventually bring Shenzhou 20 back to Earth.