Artemis 2 astronauts will double as human science experiments on their trip around the moon

Artemis 2 astronauts will be studied for how sleep, stress and radiation shape human health in deep space during their moon mission next year.

The second installment of NASA's Artemis program to return to the moon and establish a sustained human presence in deep space is set to be the first crewed flight test of its Orion spacecraft and Space Launch System (SLS) rocket. The four-person crew is tasked with putting the vessel through its paces in the cislunar environment, and performing several science experiments during their mission.

Some of that research involves the astronauts themselves, who will turn into a quartet of biomedical subjects to help NASA gather in-flight data on the human body beyond low Earth orbit for the first time in more than 50 years. As they have with hundreds of physiological tests conducted aboard the International Space Station (ISS), NASA will add the research to its growing understanding of the biological repercussions of life in microgravity, according to a recent release.

Standard measures

One of the experiments the Artemis 2 astronauts will undertake will see them join a long-running NASA effort to build a comprehensive understanding of how spaceflight affects human health. Samples of blood, urine and saliva are being collected in the months before launch, and the astronauts will undergo regular checks during their 10-day mission and follow-ups after their return.

NASA hopes to use the samples to track changes in cardiovascular health, nutrition, immunity and stress across multiple stages of training, flight and recovery.

ARCHeR: Sleep and stress tracking

The Artemis Research for Crew Health and Readiness (ARCHeR) project will investigate how crew performance might be affected by time spent as such a far distance from Earth while inside Orion's confined space, combined with the astronauts' demanding schedule.

Each Artemis 2 astronaut will wear wrist sensors to log movement and sleep throughout the mission. Pre- and post-mission evaluations will be compared to in-flight data to better understand how the deep space mission influences the crew's alertness, stress and ability to work together cohesively.

Immune system monitoring

Samples provided by the crew before, during and after their mission will also be used to study their immune systems. In this case, immune system markers in their saliva samples will help researchers evaluate how the body reacts to space radiation.

To save space and power aboard Orion during their mission, the crew is foregoing refrigeration of their in-flight saliva samples, and will instead make their deposits on specially designed dab papers, which will absorb the samples for simpler storage. Once they return, scientists will test the papers for dormant viruses triggered by the microgravity environment — a phenomenon seen aboard the ISS, where stress has been documented as a trigger to reactivate illnesses like chickenpox and shingles.

AVATAR organ-on-a-chip study

Artemis 2 astronauts will also be accompanied by thumb-sized "avatars" of themselves, in the form of blood samples grown to simulate bone marrow on organ-on-a-chip devices.

These chips will ride inside Orion as it passes through the Van Allen belts — zones of charged particles between the Earth and moon — testing how marrow responds to deep space radiation and microgravity. Results will be compared to ISS experiments to see if the chip technology can accurately predict how tissues react outside Earth's radiation-hardened magnetosphere.

Radiation

During Artemis 1, Orion carried 5,600 passive and 34 active radiation sensors. For Artemis 2, the spacecraft has been reduced to a modest six active sensors inside the cabin. Additionally, astronauts will wear personal dosimeters.

The devices will measure the consistent radiation exposure experienced throughout the mission, and detect sudden spikes from things like solar storms. If readings reach dangerous levels, astronauts can construct a makeshift radiation shield inside Orion, fortifying themselves between the spacecraft's heatshield and water storage canisters, both of which are better at absorbing penetrating radiation than other onboard materials.

NASA has selected Reid Wiseman, Victor Glover, and Christina Koch, and CSA (Canadian Space Agency) astronaut Jeremy Hansen as the crew for the Artemis 2 mission. They are scheduled to launch no earlier than Feb. 2026, with a launch window that extends through April.