At 00:11 UTC on July 4, 2021, two Chinese astronauts conducted the country’s second-ever spacewalk, this one from their new Tianhe core module. With it, China joins the United States and Russia as countries that have done EVAs from their own space stations.

The total duration of the spacewalk was nearly seven hours, far more than the first Chinese EVA on Shenzhou 7 back in 2008 which lasted twenty minutes. Despite the extended duration of the EVA, Chinese media didn’t say much about what the two astronauts, Liu Boming and Tang Hongbo, did while outside.

What is known is they attached an EVA foot restraint to the station’s robotic arm. They then used that arm to get in the right position to install a panoramic camera which had been folded against the module since launch. Taikonaut Nie Haisheng operated the robotic arm from a console inside the station. This method of close cooperation between spacewalkers and arm operators will be key for future station expansion and maintenance. This will be important as there will be at least two more modules added to the station in 2022 and 2023 respectively. 

To further add to its usefulness, the robotic arm can be controlled remotely from the ground. After being carried around on the robotic arm unfolding the camera, Tang Hongbo successfully performed an emergency airlock return drill where he had to get back to the hatch as quickly as possible as if there was a problem with his suit. This was necessary training to practice in the event of an emergency on a future EVA.

Luckily this EVA went without any major issues, and both crew members successfully returned back into Tianhe at the conclusion of their spacewalk. The preparations for and a portion of the spacewalk itself were carried on the Chinese state TV network CGTN on a time delay in typical Chinese fashion. 

The EVA also demonstrated newly designed spacesuits which were derived from the Orlan-MKS, the most recent Russian spacesuit. Compared to the U.S. EMU spacesuit, the Feitian and Orlanspacesuits are a single piece that the astronauts put on by climbing through the hinged back of the suit. The EMU is more complicated: it has separate legs and torso segments that require another astronaut’s assistance to put on. This makes it better in some respects though, as it has more flexible joints and individual parts can be changed to better suit different astronauts’ body sizes. Orlan is “one size fits most”. Both suits use about the same operating pressure, 4.3 PSI for the EMU and 5.8 PSI for the Orlan.

One suit had red stripes and the other blue to tell the different spacewalkers apart, just like the U.S. and Russian suits. The Feitian suit is capable of providing life support for seven hours, compared to the four hours of the first Chinese spacesuit that was derived from an older version of the Orlan. Additionally, the ergonomics and materials of the new spacesuit have improved, resulting in the wearer needing to expend less energy fighting against the suit to get their tasks done, compared to the old suit. Specifically, the glove was changed to make it easier to grasp things such as the safety tether hook; pretty important if you don’t want to float off into space. It’s also more comfortable to wear for extended periods, according to Taikonaut Liu in a pre-launch interview. He also participated in the first Chinese spacewalk on Shenzhou 7. On that spacewalk, he wore an actual Russian Orlan-M spacesuit.

More Information

CMS press release (Chinese)

CASC press release (Chinese)

Chinese astronauts make first spacewalk outside new station (AP)

Shenzhou 7 (Astronautix)

Learn About Spacesuits (NASA)