[Reading Science] Why Did NASA Send a 'Female' Mannequin to the Moon?

[Asia Economy Reporter Kim Bong-su] "Why did NASA send a 'female' mannequin to the moon?"

On the 18th (local time), NASA revealed the mannequins that traveled in lunar orbit for 25 days aboard Artemis 1 last November. These mannequins occupied the cockpit of the crewed spacecraft Orion, which was loaded on Artemis 1. After Orion returned on the 11th of last month, the mannequins were recovered and underwent initial inspection at Kennedy Space Center in Florida. They will then be transferred to the German Space Agency (GSA) for further analysis.

A mannequin for measuring space radiation developed by the German Space Agency (GSA). Photo by European Space Agency (ESA)

The primary purpose of these mannequins is to measure space radiation exposure and to test the radiation shielding capability of space suits. Radiation measurement devices were densely installed in both mannequins, and one was also dressed in a radiation protection vest. This is to measure how much space radiation astronauts participating in actual manned lunar exploration missions after 2025 will be exposed to. The radiation protection vest is to test how well the space suits they will wear can block radiation.

Space radiation is considered the greatest enemy of humanity's deep space exploration. Even for Mars, current technology requires over 7 months for a round trip, nearly 2 years spent in space. Even if SpaceX’s Starship under development is completed, it will take at least 80 days and up to 150 days one way. Radiation exposure during this period is fatal to humans. If a solar storm occurs, astronauts are exposed to about 40 rem of radiation in space, equivalent to undergoing 40 full-body CT scans. While not a lethal dose, long-term exposure can cause cancer. Fortunately, solar flares can be forecasted 1 to 2 days in advance. When a warning is issued, astronauts must create shielding walls made of thick metal, water, or concrete that absorb radiation well and use them as temporary shelters.

The recently released image of the Orion spacecraft recovery mannequin by NASA. Photo by NASA

Even so, about 5 rem of radiation exposure cannot be avoided. This amount is the radiation exposure limit for industrial workers in the United States. The U.S. Environmental Protection Agency explains that exposure to 5?10 rem (1 rem equals 10,000 microsieverts) changes the chemical analysis of blood, exposure above 55 rem causes nausea and fatigue, above 70 rem causes vomiting, and above 75 rem causes dizziness. Exposure to 400 rem can be fatal within two months, with higher doses causing faster death. Currently, astronauts aboard the International Space Station (ISS), located at about 410 km altitude, are exposed to radiation levels approximately 250 times higher than on Earth's surface, and in open space, this can increase up to 700 times.

Notably, both mannequins were made in the form of adult female bodies. Their names are Helga and Johar, both female names. This reflects a preliminary study anticipating changes in space exploration, such as women participating in the manned lunar landing planned for 2025. NASA plans to send astronauts including women and people of color among the approximately ten astronaut candidates currently in training to the lunar lander. This is also a corrective measure reflecting on the Apollo program of the 1970s, when only white males landed on the moon.

The two female mannequins are similar to those used in medical institutions to measure appropriate radiation doses for cancer treatment. They were created by combining 38 tissues that simulate the human body. Over 5,600 sensors are attached to major organs and tissues such as lungs, stomach, uterus, and bone marrow to measure radiation doses. Additionally, 16 active detectors measure the radiation dose received by the mannequins’ skin and internal organs during flight.

Photo of the interior of the Orion spacecraft. Photo by NASA

Attention is also focused on how well the radiation protection vest 'AstroRad' worn by Johar performed. Sponsored by the Israel Space Agency (ISA) and produced by StemRad, this vest is made of polyethylene, which better blocks harmful radiation, and it covered Johar’s upper body and uterus.

The European Space Agency (ESA) stated in 2019 during development, "We chose female mannequins because the number of female astronauts is increasing, and because female bodies are generally known to be more vulnerable to radiation."