China's Shenzhou-21 astronauts, namely Zhang Lu, Wu Fei and Zhang Hongzhang, have begun their one-month extended mission aboard the China Space Station.

The three astronauts entered the space station on November 1, 2025. Having completed a full six-month stay in orbit with excellent conditions, the trio will now work an extra month there.

The extension aims to further verify technologies for long-duration human spaceflight. During the extra month, the astronauts will focus on five key tasks.

First, they will prepare for handover. This includes wrapping up scientific experiments, sorting data and thoroughly checking payloads, cabin systems and life support equipment to get prepared for the next crew.

Second, they will pack experimental samples and equipment for return to Earth, while transferring waste to the Tianzhou-9 cargo spacecraft for later disposal.

Third, they will conduct detailed inspections of the spacecraft. This includes verifying airtight seals on hatches, checking the return module's life support systems, communication equipment, portholes and structural integrity to rule out any risks from space debris impacts.

Fourth, the crew will intensify physical training to adapt to Earth's gravity and enhance monitoring of their biorhythms, psychological state and crew compatibility to support future long-term missions.

Fifth, they will review all return procedures to ensure a safe journey.

With this extension, the Shenzhou-21 crew is set to break the previous record of 204 days in orbit set by Shenzhou-20.

So far, they have completed three spacewalks and conducted 27 scientific projects. In the coming month, the crew will also welcome the arrivals of Tianzhou-10 cargo spacecraft and the Shenzhou-23 crew.