Chinese Space Station taikonauts conduct second spacewalk

by Justin Davenport

The crew of Shenzhou-12 has conducted the second spacewalk of the mission, and the second spacewalk of the new Chinese Space Station’s lifetime. The extravehicular activity (EVA) comes two months into their planned 90-day mission in low Earth orbit.

Mission commander Nie Haisheng and first operator Liu Boming exited the Tianhe core module at 00:38 UTC on Friday, August 20. The goals of the EVA included the installation of a new panoramic camera (known as Panoramic Camera D) as well as a backup thermal control pump. Second operator Tang Hongbo stayed inside the station to support the two spacewalkers, similar to how crew onboard the International Space Station support American and Russian spacewalks.

Haisheng and Boming exited the depressurized docking node of the Tianhe module, which is being used as an EVA airlock until the Wentian lab module, equipped with its own airlock for crewmembers, arrives in the spring of 2022. Panoramic Camera D was successfully installed, and the station was prepared for future EVAs and module installations. To that end, the taikonauts finished installing additional foot restraints onto the station as well as a work platform on the station’s robotic arm.

The Shenzhou-12 taikonauts exit the Tianhe module during the first EVA in July – via CCTV

Haisheng and Boming also installed a thermal control pump as part of the Chinese Space Station’s (CSS) cooling system, which works on a similar principle to the one aboard the ISS. Since the spacecraft cannot effectively shed heat into the vacuum of space, these systems pump cooling fluid throughout the station. The pump installed on Friday’s spacewalk will act as a backup for three others that are already on the station.

The astronauts wore a set of second-generation Feitian space suits, which were reworked versions of the Feitian suit that Zhai Zhigang wore on the Chinese space program’s first-ever spacewalk in September 2008 aboard the Shenzhou-7 mission. These suits have been improved for easier mobility and can support EVAs up to eight hours in duration.

For the second CSS EVA, Haisheng’s suit had red stripes while Boming’s had blue stripes, which is similar to how the Orlan suits on the Russian segment of the International Space Station are marked to differentiate the two spacewalkers. The Feitian is also similar to the Orlan in that the astronaut enters through a door in the back of the suit, unlike the American Extravehicular Mobility Unit (EMU) which has a bottom and a top half.

The spacewalking taikonauts finished their activities one hour ahead of schedule, finishing six hours of spacewalk activity at 06:33 UTC, and the spacewalk was described as a complete success by the Chinese program. The second EVA out of the CSS in its history has also built on the first station EVA in early July, when Liu Boming and Tang Hongbo exited the station to begin installing foot restraints and the work platform on the station’s robotic arm as well as installing the first panoramic camera. Nie Haisheng remained inside the station during that first EVA.

The Long March 2F fairing separates to expose the Shenzhou crew spacecraft to the vacuum of space – via Mack Crawford for NSF/L2

The spacewalk completed today was only the third EVA in the history of the Chinese space program. However, the Chinese program has been able to apply knowledge gained from the extensive American and Soviet/Russian experience gained over the last five decades.

The third-ever NASA EVA was conducted during the Gemini 10 mission as a standup EVA by Mike Collins, who took pictures of the Milky Way galaxy in ultraviolet along with pictures of a color plate on the spacecraft. The third-ever Soviet EVA was conducted in December 1977, when Georgi Grechko and Yuri Romanenko tested the new Orlan suit for the first time during the Salyut 6 EO-1 mission.

Today’s successful EVA will be followed up by many others in the future as the Chinese Space Station assembly continues over the next year and beyond, and as the Chinese human spaceflight program moves toward a possible human landing on the Moon in the next decade or so.

(Lead image of Nie Haisheng on the CSS’s robotic arm during CSS EVA-2 – via CCTV)

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