China's Shenzhou 15 astronauts completed their third spacewalk in late March under a cloud of secrecy.
Astronauts Fei Junlong and Zhang Lu exited the Tiangong space station sometime on March 30, with crewmate Deng Qingming assisting from inside the station.
China's human spaceflight agency, CMSA, only confirmed a day later that the extravehicular activity (EVA) took place. No details of the EVA's times and tasks were published. The spacewalk followed the example of the mission's second EVA, which was only officially revealed on March 1, after it had occurred.
Related: China's Shenzhou 15 astronauts perform 2nd spacewalk and 1st 'fire in space' test (video)
Notably, the mission's first spacewalk, back in February, was a much more transparent event. The CMSA announced the EVA in advance and later reported the timing and objectives of the activity, and published video and images. This had been the practice for earlier spacewalks by crews visiting Tiangong.
It is unclear if the new restricted levels of information relate to operational sensitivity or a change in policy.
The three Shenzhou 15 astronauts have been living in orbit since arriving at Tiangong in their Shenzhou spacecraft in late November last year.
Since then, the Shenzhou 15 crew has completed a range of tasks, including maintaining the pressurized habitat aboard Tiangong, carrying out repairs, conducting scientific experiments including testing a Stirling thermoelectric converter, and installing new equipment to allow deployment of cubesats from the Mengtian science module.
The crew will greet the arrival of the Shenzhou 16 mission astronauts to Tiangong in May and hand over control of the station. Fei, Zhang and Deng will then head back to Earth, having completed their six-month-long mission.
China is currently preparing to launch the Tianzhou 6 cargo spacecraft to Tiangong to provide supplies for the upcoming mission. A Long March 7 rocket arrived at a port close to the Wenchang Satellite Launch Center in recent days. 2023 will also see China launch the Shenzhou 17 crewed mission around late November.
Follow us on Twitter @Spacedotcom and on Facebook.
