The Shenzhou XX mission crew members have conducted their second spacewalk outside the Tiangong space station, completing several assignments, according to the China Manned Space Agency.

The agency said in a news release that mission commander Senior Colonel Chen Dong and crew member Colonel Chen Zhongrui returned to the Wentian science module at 9:29 pm on Thursday after floating for six-and-a-half hours outside the colossal orbital station.

The third crew member, Colonel Wang Jie, stayed inside Tiangong to provide support, it said.

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With support from ground controllers and the use of a robotic arm, the team completed all their assigned tasks, including installing space debris shields, checking the condition of extravehicular equipment and fixing broken parts, the agency said.

They also installed foot restraints and interface adapters on the extravehicular work platform, which are designed to improve astronauts' operational efficiency during spacewalks. Subsequent spacewalks are expected to be shortened by approximately 40 minutes as a result, the agency said.

The spacewalk was the 22nd that Chinese astronauts have carried out, and marked the fifth time Chen Dong has floated outside the Chinese space station. He previously took part in three spacewalks during the Shenzhou XIV mission and was part of the Shenzhou XX's first spacewalk.

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The three orbital travelers have been aboard the station for two months since their arrival on April 25. They are conducting China's 15th manned spaceflight and have become the ninth group of astronauts aboard Tiangong, which is the only operational space station independently run by a single nation.

The astronauts have conducted a host of assignments including intra-station environmental measurements, examinations and maintenance work on instruments, and materials management since their first spacewalk on May 22. The astronauts have also conducted a series of scientific and technological work, according to the agency.