China showcased its engineering prowess on Aug. 15 as astronaut Chen Dong wore spacesuit B during Shenzhou-20's third spacewalk, marking its 20th successful extravehicular activity (EVA), according to the China Astronaut Research and Training Center on Monday.
The suit thus became the first of its kind on China's space station to achieve the lifespan extension goal of supporting 20 EVAs within 4 years.
"Spacesuit A has been used for 18 times and spacesuit B has supported 20 EVAs. Both spacesuits were sent into orbit in 2021 along with the launch of Tianzhou-2 cargo craft," said Zhang Wanxin, director of spacesuit engineering office of China Astronaut Research and Training Center.
An extravehicular spacesuit is the core equipment for astronauts during EVAs in space, ensuring their safety and enabling efficient operations outside the cabin.
The second-generation Feitian extravehicular spacesuit aboard China's space station has a service life of three years of storage in orbit, during which it can be used for EVAs no less than 15 times, in accordance with its design standards.
The extravehicular spacesuit of China's space station is the first flight product in China to conduct in-orbit lifespan assessment and extended use.
On July 15, Tianzhou-9 cargo craft delivered a new batch of supplies to China's space station, including two sets of second-generation Feitian extravehicular spacesuits, identified as D and E.
Extravehicular spacesuits D and E have been unpacked and inspected, and are in good condition. They will be gradually put into use in future EVAs, Zhang said.
China's space station spacesuit sets record with 20 successful extravehicular missions
The Exhibition Hall of Evidence of Crimes Committed by Unit 731 of the Japanese Imperial Army in northeast China's Harbin released on Thursday a 38-minute video of a former member of Unit 731, a notorious Japanese germ-warfare unit during World War II (WWII).
In the footage, former Unit 731 member Tsuruo Nishijima detailed how the unit used meteorological data to carry out bacterial dispersal and frostbite experiments.
The video was recorded in 1997 by Japanese scholar Fuyuko Nishisato and donated to the exhibition hall in 2019, according to the hall, which was built on the former site of the headquarters of Unit 731 in Harbin, capital city of Heilongjiang Province.
Nishijima joined Unit 731 in October 1938 and served in the unit's meteorological squad. The squad was not a simple observation section but rather an auxiliary force supporting the unit's human experiments in the field by measuring wind direction, wind speed and other conditions to ensure optimal experimental results.
Nishijima confirmed in the footage that "the meteorological squad had to be present at every field experiment." He testified to the "rainfall experiments" conducted by Unit 731, which involved aircraft releasing bacterial agents at extremely low altitudes.
At a field-testing site in Anda City, Heilongjiang, Unit 731 aircraft descended to about 50 meters above the ground and sprayed bacterial culture liquids onto "maruta" -- human test subjects -- who were tied to wooden stakes. Each experiment involved about 30 people, spaced roughly 5 meters apart. After the experiments, the victims were loaded into sealed trucks and transported back to the unit, where their symptoms and disease progression were recorded over a period of several days.
Nishijima also revealed that a Japanese military doctor once died after removing the mask and becoming infected during an experiment, indirectly proving the extreme virulence of the bacterial agents.
The video further disclosed details of the meteorological squad's involvement in frostbite experiments. To study wartime needs in frigid regions, the invading Japanese army forced the victims to expose their bodies for five to ten minutes in temperatures ranging from minus 20 to minus 35 degrees Celsius and observed their physical reactions.
"For example, during frostbite experiments, we would be sent outside to observe the weather. They wouldn't bring many people out at once, only two or three, who would be forced to take off their upper garments or all their clothes. In fact, it was already quite tough to stay out there for five to ten minutes, because it was too cold," Nishijima said.
According to the exhibition hall, Unit 731 had a separate frostbite laboratory, with Hisato Yoshimura serving as the leader of the unit's frostbite study squad from 1938 to 1945.
In a paper on frostbite published in 1941, Yoshimura recorded data from live human experiments to study the occurrence of frostbite and pathological changes in the human body under different conditions.
"This is a form from the paper. Titled 'The Severity and Process of Frostbite,' it divides frostbite into three stages. The symptoms of the first-degree frostbite are redness and swelling. Blisters appear in the second stage. And the third-degree frostbite features necrosis and ulceration. It says here that, in the third stage, from the 50th to the 60th day, toes and fingers detached. There is no doubt that these data were obtained through numerous human experiments," said Tan Tian, a researcher of the exhibition hall.
Nishijima's video, a piece of oral history from a perpetrator's perspective, further reconstructs the criminal chain of Unit 731 and once again demonstrates that the invading Japanese army's biological warfare crime was systematic and inhumane, and was an undeniable historical truth, according to the exhibition hall.
"Unit 731's frostbite experiments were essentially conducted to prevent and treat frostbite during combat in cold environments. However, for the so-called prevention and treatment of frostbite, they caused frostbite on living people for experiments and data analysis. So in nature, it still serves the purpose of war," said Jin Shicheng, director of the Department of Publicity, Education and Exhibition at the hall.
Unit 731 was a top-secret biological and chemical warfare research base established in Harbin as the nerve center for Japanese biological warfare in China and Southeast Asia during WWII.
At least 3,000 people were used for human experiments by Unit 731, and more than 300,000 people in China were killed by Japan's biological weapons.
Video offers new evidence of Japan's wartime germ-warfare crimes in northeast China
