China's Shenzhou 15 astronauts have completed the fourth and final spacewalk of their six-month-long mission.
Mission commander Fei Junlong and Zhang Lu embarked on the extravehicular activity (EVA), exiting via the Wentian science module airlock of the Tiangong space station on Saturday (April 15) Beijing time. Crewmate Deng Qingming assisted operations from inside the outpost.
Fei and Zhang's tasks included installing an external pump set, which is part of Tiangong's coolant system, onto the Mengtian science module. Other completed objectives were installing inter-module cables and devices to support a science and experiment payload hosting platform, according to a statement from the China Manned Space Agency.
Related: China's Shenzhou 15 astronauts quietly conduct 3rd spacewalk (video)
Shenzhou 15's total of four EVAs during their stay aboard Tiangong is a new national record. The crew had completed their third spacewalk in late March.
As with recent Chinese spacewalks, the activity was conducted without any prior official notification and only few details released after the event. EVAs during the Shenzhou 12, 13 and 14 missions when the three-module Tiangong was being constructed were conducted in a more open fashion.
Fei, Zhang and Deng are expected to leave Tiangong next month, after they greet the upcoming Shenzhou 16 mission astronauts and hand over control of the station.
Before this, they will oversee the arrival of the Tianzhou 6 cargo spacecraft to provide fresh supplies to Tiangong for the upcoming mission. The Long March 7 rocket to launch that mission is currently being prepared at Wenchang Satellite Launch Center on the island province of Hainan.
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