These avatars will fly around the moon with NASAs Artemis 2 astronauts

When the Artemis II spaceship carries four astronauts around the moon, it will also bring four miniature proxies of the crew made from their own cells. 

Alongside crew commander Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen will fly lab-grown tissue samples designed to mimic parts of the crew's bodies, particularly bone marrow, a key component of the immune system. The NASA experiment, called AVATAR — short for A Virtual Astronaut Tissue Analog Response — aims to show how living human cells respond to deep-space radiation and weightlessness.

Before launch, which could occur as early as March 6, doctors will draw blood from each crew member. Scientists will then grow cells from those samples and place them into chips about the size of a computer thumb drive. During the 10-day mission, the chips will soak up the same radiation and microgravity as their human counterparts. 

"This is a small experiment, but it could lead to really big impacts for healthcare, both for our astronauts, but also people here back on the earth," said Jacob Bleacher, NASA’s chief exploration scientist.

Artemis II marks NASA's first crewed mission beyond low-Earth orbit since Apollo — and the first to place biomedical research at the center of a lunar flight. The Orion spaceship, named Integrity by the crew, will travel beyond Earth's protective magnetic bubble, exposing the astronauts to radiation levels far higher than those aboard the International Space Station. That's an opportunity for scientists to begin writing the playbook for interplanetary travel, learning how to keep humans alive in the unforgiving wilds of space. 

Outside the ship, space is vast — incomprehensibly so. But inside the capsule, "space" is among the scarcest resources. Orion's habitable area is closer to a studio apartment than a space station, shaping everything from how astronauts move to how they store biological samples. NASA researchers have built that constraint into the studies themselves.

Immune Biomarkers study

One investigation, known as Immune Biomarkers, focuses on how deep space alters immune systems. Previous research has shown that spaceflight can weaken immune responses and awaken dormant viruses, such as shingles and cold sores. 

Because Orion lacks refrigeration, astronauts will collect their spit by licking treated paper like stamps and storing them in small booklets. Scientists will rehydrate the samples after the capsule returns to Earth.

"Saliva is basically a window into how our immune system is functioning," Bleacher said.  

Archer study

Another study, Artemis Research for Crew Health and Readiness (Archer), will examine how astronauts sleep, think, and get along in deep space. Crew members will wear wrist devices, similar to a Fitbit, to monitor their activity and rest. Researchers will pair that data with cognitive testing and behavioral assessments. 

The fitness trackers will also help NASA study how the foursome handle exercising in Orion's confined quarters, where increased breathing will raise carbon dioxide levels.

Spaceflight Standard Measures study

A third effort, Spaceflight Standard Measures, extends a health-monitoring program NASA began in low-Earth orbit in 2018. Astronauts will provide blood, urine, and saliva before and after the mission and complete tests of balance, strength, and endurance. 

Microgravity takes a toll on astronauts' bones and muscles, but NASA wants to know how quickly the crew can bounce back to physical labor. Shortly after splashdown off the California coast, the crew will don spacesuits and complete a simulated spacewalk and obstacle course to gauge their recovery.

After all, if NASA wants to send humans on a months-long journey to Mars, those astronauts won't have rehab to get them in shape once they arrive.

Radiation exposure study

Radiation remains one of the largest unknowns for long-duration space travel. Earth's magnetic field and the Van Allen radiation belt, a zone of charged particles around the planet's magnetosphere, help shield low‑orbiting spacecraft like the space station from much of the sun's outbursts and cosmic rays. But Artemis II will go beyond that, into a more hostile radiation environment. 

Artemis II astronauts will carry personal radiation sensors in their pockets, while detectors mounted throughout the cabin will track exposure levels. Additional monitors developed with the German Space Agency will measure high-energy particles believed to pose increased health risks.

AVATAR study

Radiation data will also inform one of the mission's most unusual experiments: the organ-on-a-chip devices containing the crew's living cells.

NASA will house the AVATAR tissue chips in a battery-powered box that regulates temperature and nutrient delivery throughout the flight. After the mission, scientists will analyze how gene activity changed within individual cells, comparing flight samples with copies on Earth. 

The work aims to reveal how deep-space radiation and weightlessness affect the development of blood cells. And it will also serve as a test case for whether these chips can predict health outcomes.

"This will be very important for building both our understanding of the stresses of just doing the very first Artemis II, but [also] later on, as we go and establish a sustained presence on the moon and then hopefully go to Mars," said Mark Clampin, deputy associate administrator for NASA science. "It's a way, maybe in the future, that we can actually build [personalized] health kits that help us ensure our astronauts are safe."