The human body is a complex machine fine-tuned—over millions of years of evolution—to function here on Earth. So what happens to that device when you put it in a box and throw it beyond the safety of our planet’s atmosphere?
This is, in very simplified terms, a question that biomedical researchers at NASA have been asking for decades. These scientists study the health effects of spaceflight to develop ways to protect the bodies and minds of astronauts, using ground-based laboratories, analog space, and the International Space Station to conduct advanced studies.
Now that NASA is finally returning humans to the Moon, these scientists are preparing for the research opportunity of a lifetime.
The Artemis 2 mission will send NASA astronauts Reid Wiseman, Victor Glover, Christina Koch, and Canadian Space Agency astronaut Jeremy Hansen farther from Earth than any human has ever been. During their 10-day flight around the Moon, they will encounter high levels of cosmic radiation and reach a maximum distance of 250,000 miles from Earth. The campaign is currently on track to be launched in the first week of February.
“I often talk about the most complex system in this vehicle is going to be a human,” Steven Platts, senior scientist for the Human Research Program at NASA’s Johnson Space Center, told Gizmodo. “We need to understand exactly what is going to happen to prevent anything bad from happening and keep them safe and healthy.”
The dangers of deep space
If Platts and his colleagues have learned anything from their decades of research, it’s that spaceflight puts a lot of strain on the human body. He explained that there are five main health hazards associated with spaceflight: radiation, isolation and confinement, distance from Earth, gravity (or lack thereof), and hostile, confined environments.
These risks manifest differently depending on the machine profile, Platts said. The Artemis 2 crew will spend much less time in microgravity than astronauts on regular ISS missions, for example. However, 10 days is long enough to initiate certain physiological changes, such as fluid replacement and vestibular disturbances.
When it comes to radiation, Artemis 2 astronauts will receive a much higher daily dose than those aboard the ISS. They will travel across the Van Allen belts—two donut-shaped areas of particle radiation trapped within Earth’s magnetic field—and into the galactic cosmic ray region beyond the magnetosphere.
The Orion spacecraft—which will carry the Artemis 2 astronauts on this trip—is designed to protect its crew from most of this radiation, but measuring how much it breaks down and how human cells and DNA react to it is important.
Galactic cosmic rays can be very dangerous. If you look at individual cells exposed to these high-energy particles, “you can literally see the tracks the radiation makes through the cell and the damage it does,” Platts said.
Orion is equipped with thousands of sensors that will measure radiation levels inside the spacecraft. Each crew member will also carry a sensor called a Crew Active Dosimeter in their pockets to closely monitor their exposure levels.
Understanding how the human body responds to the unique hazards of the deep space environment will be important for future moon landings and Mars missions. Artemis 2 will explore this in many different ways.
Transforming astronauts into living science experiments
During this mission, team members will work as researchers and test subjects, collecting data that will help NASA develop interventions, protocols, and preventive measures to protect astronaut health. Another study, called ARCheR (Artemis Research for Crew Health and Readiness), will investigate how the deep environment of space affects sleep, stress, cognition, and teamwork, all of which are key to astronaut health and performance.
Participating team members will wear wristbands that continuously monitor their movement and sleep patterns throughout the campaign. This data will support real-time health checks and safety checks, while pre-flight and post-flight tests will provide insight into any changes in attitude, behavior, and sleep quality.
The Artemis 2 astronauts will also provide wet saliva samples before and after the mission, as well as dry saliva samples during the mission. When in flight, they will wipe saliva on a special type of pocket notebook paper, eliminating the need for a wet sample refrigeration system on the Orion spacecraft.
Saliva is an excellent indicator of human health, as it contains a rich mixture of biomarkers that indicate the functioning of the immune system. “We can see hormones, we can see bacteria, we can see other chemicals in the blood … And through this process, we can see changes in cortisol,” Platts said. Measuring how this stress hormone fluctuates during work will be important, since stress is associated with many negative health effects of spaceflight, he explained.
These are not the only biological samples NASA will collect from the Artemis 2 crew, however. They will be the first astronauts in deep space to participate in the Spaceflight Standard Measures study, which has been collecting blood, urine, and saliva samples from astronauts aboard the ISS and elsewhere since 2018. These samples help researchers assess the astronauts’ nutritional status, cardiovascular health, and immune function.
Then there’s Avatar, the most exciting biomedical study aboard Artemis 2. Briefly titled “Astronaut Analog Tissue Response,” Avatar consists of USB-sized “ortho chips” containing living human cells grown inside tiny, fluid-filled channels. These chips are designed to mimic the structure, function, and physiological responses of human organs.
To make them, the Artemis 2 astronauts first donated blood platelets to the local health care system. The remaining cells in their samples contained a small number of bone marrow-derived stem cells, which NASA researchers then purified and placed on chips alongside blood vessel cells and other supporting cells.
“The chip will work the same way as our bone marrow,” Platts explained. Flying these chips on the Artemis 2 mission—and the astronauts who created them—will allow NASA scientists to compare changes in the chip with changes in the astronaut’s actual bone marrow.
“Think about the planes coming,” Platts said. “If I’m going to fly in two years, [NASA] they can fly my tissue—my avatar—ahead of time and bring it back and see what happens so they can create countermeasures for me, for my own use.” Artemis 2 will be the first mission to fly with this biotechnology.
Together, these studies will generate a wealth of data, helping to pave the way for NASA’s return to the lunar surface and extend human access to the depths of the solar system. “It’s amazing how many things we will be able to find in this one machine,” said Platts.
