Canadian astronaut Jeremy Hansen's historic journey around the Moon lasted just days, but its implications continue and will stretch far further despite breaking a spaceflight record.
As part of Artemis II, Hansen and three crewmates became the first humans in more than 50 years to travel beyond low Earth orbit, reaching a distance of roughly 400,000 kilometres from Earth before splashing down safely in the Pacific Ocean.
The mission was a test flight for future lunar exploration. It was also a reminder of something less visible, but increasingly urgent: the farther humans travel from Earth, the more exposure to space radiation becomes a defining biological risk.
That question - how radiation affects the human body over time and distance - will be central not only to sustained missions to the Moon, but to any eventual attempt to reach Mars.
At Western University and Canadian Nuclear Laboratories (CNL), researchers are working on potential answers through a technology small enough to fit in the palm of a hand.
Controlled but complex
Tamie Poepping and second-year astrophysics student Aya Majzoub at a custom micro particle image velocimetry (MicroPIV) system, comprised of a laser and high-speed camera coupled to an inverted fluorescent microscope, for investigating organ and organoid-on-chips. (Christopher Kindratsky/Western Communications)
Physics and astronomy professor Tamie Poepping is advancing organ-on-chip and organoid-on-chip systems that replicate the complexity of human tissue inside transparent chambers no larger than a postage stamp. (Organoids are miniaturized, simplified versions of an organ produced in a lab.)
Inside these chambers, nutrient-rich fluid moves through intricate networks of channels designed to mimic blood flow, keeping clusters of living human cells alive while allowing researchers to observe how they react under stress.
"They look very small and controlled, but they're designed to recreate incredibly complex biological systems," said Poepping, director of Western's Biofluidics Research Lab.
Her lab specializes in building platforms capable of controlling fluid at near-cellular scales. That precision allows researchers to isolate variables, monitor tissue behaviour in real time and study how organs respond to extreme environments.
"It's about emergency response, how systems react and how we respond to that reaction," said Poepping. "It was actually a bit coincidental, but I was watching Chernobyl on Netflix at the same time this project started and kept thinking, this is exactly the kind of complexity we're trying to capture."
Poepping's organ- and organoid-on-chip devices have become foundational to a broader collaboration focused on radiation exposure.
An organoid-on-chip is a tiny microchip lined with living human cells that mimics the physical, chemical and mechanical functions of real organs. (Christopher Kindratsky/Western Communications)
Exploring the extremes
Working alongside Poepping, physics and astronomy professor Eugene Wong studies how humans, organs, tissues and cells respond to radiotherapy. Exposing these organs and organoids-on-chip to radiation allows the study of detailed biological effects and individual variations.
The long-term goal for Wong is to not only better understand both acute and delayed tissue damage in cancer patients, but those individuals in environments that are difficult to study like astronauts in deep space and engineers and scientists working with nuclear reactors.
This is no new area of study for Wong. His connection to this research stretches back decades. As a post-doctoral fellow, he worked under Jerry Battista, Western's professor emeritus in medical biophysics, whose pioneering work helped shape modern understanding of radiation exposure in extreme environments like space travel.
Battista helped frame radiation exposure not as a uniform dose applied to tissue, but as a dynamic process with effects that vary across time, space and biological structure. Ten years ago, he wrote a textbook chapter titled Radiation Exposure on a Voyage to Mars: All Aboard?, that continues to influence both medical radiation research and space science today. Now Wong is extending that work into entirely new environments.
"We know astronauts are being exposed to radiation, but we don't fully understand what that means at the tissue level over time," said Wong. "Before we send humans farther into space, maybe we send miniature versions of human organs and organoids first and learn from them."
Together, Poepping and Wong are helping develop new systems where organoids could eventually be housed inside tiny chips and sent into space to monitor radiation exposure in real time before humans travel farther from Earth.
Researchers (L to R) Eugene Wong, Christopher Pin and Tamie Poepping (Christopher Kindratsky/Western Communications)
Slice of life
But understanding radiation damage also requires understanding how biology itself varies.That's where Christopher Pin enters the collaboration.
A professor in the departments of physiology and pharmacology, oncology and paediatrics at Western's Schulich School of Medicine & Dentistry, Pin studies why patients with similar cancers can respond very differently to the same treatments.
Physiology and pharmacology graduate student Gavin Goebel, member of the research team at Baker Centre for Pancreatic Cancer, works on an organoid-on-chip. (Christopher Kindratsky/Western Communications)
In his lab at London Health Sciences Centre Research Institute (LHSCRI), Pin and his team grow organoids to study those differences directly. The researchers have found even within the same cancer type, responses to radiation and chemotherapy can vary dramatically.
"They don't all behave the same way," said Pin, lead translational scientist at LHSCRI's Baker Centre for Pancreatic Cancer. "That variability is the problem."
Traditional models, from flat cell cultures to animal testing, often fail to replicate what happens inside the human body with enough precision. Organoid systems offer something more realistic, simplified biological models that remain complex enough to behave like living tissue.
When paired with Poepping's engineering systems and Wong's radiation expertise, they create a platform capable of answering questions researchers previously couldn't study in real time.
At CNL, researchers Antonella Bertucci and Marcelo Vazquez are adapting these systems for radiobiology experiments related to emergency response and triage scenarios and space radiation exposure. The development of organ- or organoid-on-chip technology allows Bertucci and Marcelo to study biological effects of different types of radiation using Earth-based laboratories, like the Biological Research Facility in Chalk River, or in space.
Rather than measuring only whether cells survive radiation exposure, CNL researchers can now observe intermediate biological responses like metabolites, cytokines and stress markers that reveal how damage unfolds and how tissue attempts to recover.
"We can start to see not just whether cells survive, but what they're doing while they respond," said Wong. "And the implications extend far beyond space travel. In cancer treatment, the work could help explain why identical radiation doses produce vastly different patient outcomes. In nuclear safety, it could improve how exposure is measured and how emergency responses are developed."
This collaboration, partially supported by NSERC and Western's Institute for Earth and Space Exploration, will importantly engage trainees in research placements funded by collaborative grants at CNL in Chalk River, Ontario, this summer.
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