Radiation-Shielding Vest Aced Artemis I Lunar Test, Could Protect Astronauts on Moon and Mars Missions

A special vest designed to protect astronauts from dangerous space radiation passed an important test during NASA's Artemis I moon mission in late 2022. The vest, called AstroRad, was made by an Israeli company called StemRad. Scientists found that the vest could cut the amount of harmful radiation an astronaut receives by nearly 60% during a major solar storm. This discovery could be a big step toward keeping astronauts safe on future trips to the moon and even Mars.

Space is full of radiation, especially from the sun. Sometimes the sun releases huge bursts of energy called solar particle events. These bursts send streams of dangerous particles flying through space. A single large solar storm can seriously raise an astronaut's lifetime risk of getting cancer from radiation.

NASA's Artemis program wants to send humans back to the moon for the first time in more than 50 years. One of the biggest challenges is protecting astronauts from these sudden, unpredictable solar storms. Covering an entire spacecraft with thick radiation shielding would be too heavy to launch into space. That is why scientists began looking at protective clothing as a solution.

AstroRad was built by the Israeli startup StemRad, with help from the Israel Space Agency and aerospace company Lockheed Martin. Instead of using lead — which is common for blocking radiation on Earth — the vest uses a special high-density plastic that is rich in hydrogen. Hydrogen is very good at stopping dangerous space particles without creating new harmful radiation the way lead can. The plastic is also much lighter than lead, which is important for space travel where every pound matters.

The vest is made of thousands of small, hexagonal rods of this rigid plastic, fitted together like fish scales to keep the garment flexible. Each vest weighs about 57 pounds, or 26 kilograms. Scientists chose to build a vest rather than a full-body suit because different parts of the body are more sensitive to radiation than others. By putting the most shielding where it matters most, the vest gives about 30% better protection than if the same amount of shielding were spread evenly all over the body.

To test the vest, researchers used two highly detailed dummies called phantoms during the Artemis I mission. The phantoms were shaped like adult women, because studies show that certain female organs — like breasts and ovaries — are especially vulnerable to radiation damage. Each dummy was packed with more than 5,600 radiation sensors inside and on its surface. One dummy, named Zohar, wore the AstroRad vest, while the other, named Helga, did not.

Both dummies flew inside NASA's Orion spacecraft on its 26-day trip to lunar orbit and back. While Orion did not run into a major solar storm during the mission, scientists were still able to study how much radiation the dummies absorbed. They used that data to calculate how the vest would have performed during past solar storms. For a powerful storm that occurred in August 1972, the AstroRad vest would have cut radiation exposure by nearly 60%.

The team had expected a reduction of about 45%, so the stronger result was a big surprise. Scientists double-checked their work and confirmed that the targeted shielding approach was even more effective than they had planned. That level of protection could save an astronaut from the equivalent of up to 193 extra days of deep-space radiation exposure. Researchers say this makes AstroRad one of the most promising tools yet for long-duration space missions.

Astronauts would not wear the vest all the time — it is meant to be used during emergencies when solar radiation levels suddenly spike. It might need to be worn for just a few hours or a few days at a time. During tests on the International Space Station, some crew members even wore the vest while sleeping. One major advantage is that it gives roughly the same protection as a spacecraft's built-in storm shelter, while still letting astronauts move around and keep working.

Scientists are now studying whether AstroRad parts could be made in space using a 3D printer and recycled materials already on board a spacecraft. A test on the International Space Station already showed this might be possible. If it works, future crews could print new vest parts without needing to bring all the materials from Earth. The researchers published their findings on August 12 in the journal Science Advances.