Beyond the shelter of Earth's magnetic field, invisible radiation has long stood as one of the most formidable barriers to human exploration of the cosmos. An Israeli company, StemRad, may have quietly shifted that calculus: a targeted radiation-shielding vest tested aboard NASA's Artemis I mission in 2022 demonstrated reductions in astronaut exposure of up to 60 percent during modeled solar storm scenarios, suggesting that the ancient human instinct to protect the body's most vital parts may translate meaningfully into the language of deep space. The results, published in Science Advances and
Israeli radiation vest shows promise for safer deep-space missions
Targeted protection proved 30% more effective than spreading shielding evenly
Mark
Why does radiation matter so much for deep-space missions? Isn't the spacecraft itself a shield?
Mimi
The spacecraft provides some protection, but it's not enough. Solar storms can release enormous bursts of radiation, and once you're beyond Earth's magnetic field, there's nothing to hide behind. Astronauts on the Moon or Mars for weeks or months face cumulative exposure that could increase cancer risk and damage the nervous system. The vest doesn't solve the problem entirely, but it buys time.
Mark
So they tested this on mannequins, not actual people. How do we know it will work for humans?
Mimi
That's the honest limitation. The sensors on Helga and Zohar measured radiation reaching different body parts, and the data was real. But the solar storm itself was modeled—they used historical data from 1972 and 1989 to simulate what would happen. It's the best you can do without waiting for an actual storm to hit astronauts in space.
Mark
The weight—57 pounds—that seems heavy for something an astronaut has to wear.
Mimi
It is. But the point is that targeted protection is more efficient than spreading that weight evenly. You're protecting the organs that matter most. An astronaut on a Moon mission might wear it during high-risk periods, not the entire time.
Mark
What happens next?
Mimi
Israeli teams are proposing more experiments for Artemis III. If NASA approves them, we'll get more data from actual crewed missions. That's when we'll really know if this works in practice.
The Pulse
- Radiation beyond Earth's magnetic shield is not a distant risk but an ever-present threat capable of ending a mission — or a life — during a single severe solar storm.
- Rather than armoring the whole body at prohibitive weight, StemRad's AstroRad vest targets only the organs most vulnerable to radiation damage, a focused strategy that proved 30% more effective than conventional whole-body shielding of equal mass.
- Two instrumented mannequins — one vested, one bare — flew the 25.5-day Artemis I lunar circuit, generating real-space radiation data that researchers then stress-tested against the most catastrophic solar storms on record.
- Modeled against the ferocious 1972 solar storm, the vest cut exposure by 60.7%; even against the harder, more penetrating 1989 event, it held at 38.5% — potentially adding 40 to 193 days of safe mission time.
- Israeli teams have already submitted Artemis III experiment proposals, with some clearing NASA's initial review, signaling that this vest may become standard equipment on the road to Mars.
Beyond the shelter of Earth's magnetic field, invisible radiation has long stood as one of the most formidable barriers to human exploration of the cosmos. An Israeli company, StemRad, may have quietly shifted that calculus: a targeted radiation-shielding vest tested aboard NASA's Artemis I mission in 2022 demonstrated reductions in astronaut exposure of up to 60 percent during modeled solar storm scenarios, suggesting that the ancient human instinct to protect the body's most vital parts may translate meaningfully into the language of deep space. The results, published in Science Advances and born of international collaboration, point toward a future in which longer journeys to the Moon and Mars become not merely imaginable, but survivable.
In the vacuum beyond Earth's protective magnetic field, radiation is an invisible adversary that no conventional armor can fully stop. StemRad, a Tel Aviv-based company founded in 2011, approached the problem differently: instead of wrapping the entire body in heavy shielding, its AstroRad vest concentrates protection on the organs most susceptible to radiation damage — bone marrow, lungs, stomach, colon, breasts, and ovaries — using a dense, hydrogen-rich plastic arranged in a honeycomb pattern. The prototype weighed roughly 26 kilograms.
To test the vest under genuine space conditions, NASA flew two human-torso mannequins on the 25.5-day Artemis I mission around the Moon in late 2022. One mannequin, Zohar, wore the AstroRad vest; the other, Helga, did not. Thousands of embedded radiation sensors recorded exposure throughout the journey. Because no solar storm occurred during the flight, researchers used the real mission data to calibrate computer models simulating severe historical events.
The results were striking. Against a modeled 1972 solar storm, the vest reduced radiation exposure by 60.7 percent; against the more penetrating 1989 storm, by 38.5 percent. Those reductions could extend safe mission windows by 40 to 193 additional days depending on the scenario. The targeted design also outperformed whole-body shielding of equivalent weight by roughly 30 percent — a meaningful efficiency gain when every kilogram launched into space carries a cost.
The experiment, known as MARE, was a collaboration among the German Aerospace Center, NASA, the Israel Space Agency, Israel's Ministry of Innovation, Science and Technology, and StemRad. Its findings were published in Science Advances. Israeli teams have since submitted proposals for Artemis III experiments, with some already passing NASA's initial review — a signal that as humanity reaches toward the Moon and Mars, this vest may travel with it.
In the vacuum beyond Earth's protective magnetic field, radiation becomes an invisible threat that no suit of armor can fully stop. But an Israeli company may have found a way to make deep-space travel safer. A vest designed to shield the organs most vulnerable to radiation damage was tested aboard NASA's Artemis I mission in late 2022, and the results suggest it could reduce astronaut exposure by as much as 60 percent during a severe solar storm.
The vest, called AstroRad, was built by StemRad, a Tel Aviv-based company founded in 2011. Rather than wrapping the entire body in shielding material—which would be heavy and cumbersome—the designers focused protection on the organs at greatest risk: bone marrow, lungs, stomach, colon, breasts, and ovaries. They used a dense, hydrogen-rich plastic arranged in a honeycomb pattern. The prototype weighed about 26 kilograms, or roughly 57 pounds.
To test the vest in actual space conditions, NASA sent two mannequins shaped like human torsos on the 25.5-day Artemis I journey around the Moon and back. One mannequin, nicknamed Zohar, wore the AstroRad vest. The other, Helga, did not. Both were fitted with thousands of radiation sensors to measure how much radiation penetrated to different parts of the body. The mission itself did not encounter a solar storm, so researchers used computer models calibrated against the real radiation data collected during the flight to estimate how the vest would perform in a severe event.
When modeled against a severe solar storm from 1972, the vest reduced radiation exposure by 60.7 percent. Against a 1989 storm with more penetrating radiation, it reduced exposure by 38.5 percent. These reductions could extend the period astronauts could safely remain in space by roughly 40 to 193 additional days, depending on the scenario—though researchers emphasized these were model estimates, not guarantees. The targeted approach also proved significantly more efficient than spreading shielding evenly across the body; the vest provided about 30 percent more effective protection than a whole-body configuration of the same weight.
The experiment, called MARE (Matroshka AstroRad Radiation Experiment), was a collaboration between the German Aerospace Center, NASA, the Israel Space Agency, Israel's Ministry of Innovation, Science and Technology, and StemRad. Ran Levana, director of the Israel Space Agency, called it an important step forward—a transition from simply measuring radiation in space to testing practical solutions under real mission conditions. StemRad CEO Oren Milstein described the test as a formative milestone for the company and expressed hope that the vest would become a lasting contribution to NASA's human spaceflight program and open doors for more Israeli astronauts to fly on future missions.
The findings were published in the peer-reviewed journal Science Advances. Israeli teams have already submitted proposals to conduct additional experiments aboard Artemis III, NASA's planned next crewed Moon mission, with some proposals passing the agency's initial review. Final approval will depend on NASA's assessment of safety, readiness, and scheduling. The work signals that as space agencies push toward longer missions to the Moon and Mars, Israeli innovation may play a crucial role in keeping astronauts safe from the radiation that lies in wait beyond Earth's protective shield.
Notable Quotes
An important transition from measuring the radiation environment in space to evaluating practical countermeasures that can be tested under mission conditions— Ran Levana, director of the Israel Space Agency
A formative test for AstroRad in deep space and a significant milestone for StemRad— Dr. Oren Milstein, StemRad CEO
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