For decades, the International Space Station (ISS) has served as a floating laboratory, providing a glimpse into how the human body adapts to microgravity. But as NASA prepares to push further into the void, the safety margins are changing. The upcoming Artemis II mission is designed to do more than just orbit the Moon; It’s a critical biological experiment intended to help Artemis astronauts to shed light on space health risks that simply do not exist in low Earth orbit.
While the crew will be shielded from the vacuum of space by the Orion capsule, they will be venturing far beyond the protective embrace of Earth’s magnetosphere. This magnetic shield deflects the majority of radioactive cosmic rays and solar particles that would otherwise ravage human tissue. On the ISS, astronauts are relatively safe; however, a trip to the Moon takes humans more than 1,000 times the distance from Earth than the orbiting station, exposing them to the raw environment of deep space.
Understanding this exposure is not merely a matter of curiosity—it is a prerequisite for survival. As NASA looks toward establishing a permanent lunar base and eventually launching crews to Mars, the agency must determine how to protect humans from a silent, invisible threat that can alter DNA and degrade cognitive function over time.
The invisible threat: Galactic vs. Solar radiation
Radiation in deep space is not a monolithic danger. NASA scientists distinguish between solar particle events—bursts of radiation from the Sun—and galactic cosmic radiation (GCR). While solar flares are intense and episodic, GCRs are a constant background hum, originating from high-energy events like supernovas across the universe.
Steven Platts, chief scientist for the NASA Human Research Program, notes that the team expects to see a significant increase in galactic cosmic radiation during the mission. Unlike solar radiation, which can sometimes be mitigated by shielding, GCRs are highly penetrating and difficult to block.
The health implications extend far beyond the well-known risk of cancer. Radiation can cause systemic inflammation and impact the central nervous system and blood circulation. According to Platts, this inflammation in the brain is a particular concern, as it may increase the long-term risk of developing neurodegenerative conditions, including Parkinson’s disease.
Hardware for biology: The ‘organ-on-a-chip’
To track these changes without relying solely on human subjects, NASA is employing a fascinating blend of biotechnology and hardware engineering. The Orion capsule will carry state-of-the-art computer chips designed to replicate human physiological functions—essentially “organs-on-a-chip.”
For this mission, planners have focused on mimicking bone marrow. Because bone marrow produces the body’s blood cells, it is among the tissues most susceptible to radiation and other environmental stressors. By monitoring these synthetic biological systems alongside the crew, scientists can gather high-fidelity data on how deep-space radiation degrades cellular structures in real-time.
This approach is supplemented by a rigorous biological monitoring regime. NASA has collected blood samples from the crew before takeoff to establish a baseline, which will be compared with post-trip samples. Throughout the journey, astronauts will provide saliva samples and wear smartwatches to monitor vital signs, creating a comprehensive data map of the body’s reaction to the lunar environment.
The psychological toll of the ‘camper van’
While radiation is the primary physical hurdle, the psychological risks of deep space travel may be equally daunting. The transition from the ISS to the Orion capsule represents a massive shift in living conditions. Steven Platts describes the difference as moving from a “six-bedroom house, like a mansion… To a camper van.”
The ISS offers relatively ample space and a constant, comforting view of Earth. In contrast, the Orion capsule is a cramped environment where four astronauts must coexist in tight quarters for the duration of the mission. This confinement, coupled with the profound disconnection from Earth as the planet shrinks to a small blue dot, creates a unique set of psychological stressors.
Bruce Betts, chief scientist at the Planetary Society, points out that while the Apollo astronauts were studied extensively, the technology and psychological understanding of the last 50 years have evolved. The current mission will provide a modern medical dataset that the Apollo era simply could not produce.
| Factor | International Space Station (LEO) | Artemis (Deep Space/Lunar) |
|---|---|---|
| Radiation Shielding | Protected by Earth’s magnetosphere | Minimal to no magnetospheric protection |
| Primary Radiation Source | Solar particles / Van Allen belts | Galactic Cosmic Radiation (GCR) |
| Living Volume | Large, modular compartments | Compact Orion capsule |
| Earth Connectivity | Near-instant communication/visibility | Significant distance/visual isolation |
The roadmap to Mars
The 10-day duration of the Artemis II mission means that acute radiation poisoning is unlikely. However, the data gathered will serve as the blueprint for missions that last months or years. If NASA intends to put boots on the ground for extended lunar stays, they must solve the radiation puzzle first.
The findings from the bone marrow chips and the crew’s biological samples will help engineers design better shielding for future lunar habitats and Mars transit vehicles. It will also allow flight surgeons to develop personalized medical interventions to mitigate the inflammatory responses caused by GCRs.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. For health concerns related to radiation or neurological health, please consult a licensed healthcare provider.
The next major milestone for the program will be the subsequent Artemis missions, which aim to land the first woman and first person of color on the lunar surface, moving from orbital research to long-term habitation studies.
What do you think is the biggest hurdle for humans becoming a multi-planetary species? Share your thoughts in the comments below.
