Artemis II Astronauts Face Radiation Risks During Lunar Mission

Space scientist Patricia Reiff explains the dangers of solar flares and cosmic rays for the upcoming crewed flight around the moon.

Apr. 1, 2026 at 6:48pm

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NASA's Artemis II mission will send astronauts on a historic flight around the moon, exposing them to increased space radiation. Space scientist Patricia Reiff discusses the risks of solar flares, coronal mass ejections, and galactic cosmic rays, and explains why the current solar maximum period may actually be a safer time to launch the mission.

Why it matters

Artemis II will be the first crewed mission to the moon since the Apollo era, providing a rare opportunity to study the health impacts of deep space radiation on astronauts. Understanding these risks is crucial for planning future long-duration missions to the moon and Mars.

The details

During the Artemis II mission, astronauts will face two main sources of dangerous radiation: solar energetic particles from solar flares, and galactic cosmic rays. Solar flares can emit highly energetic particles that can penetrate spacecraft hulls, while galactic cosmic rays pose a constant background threat that is difficult to shield against. However, Reiff notes that the current solar maximum period may actually be a safer time to launch, as the stronger solar wind helps clear out cosmic rays from the inner solar system.

  • Artemis II is scheduled to launch in 2024, during the sun's current peak of activity.
  • A powerful solar flare in August 1972 could have delivered a nearly lethal dose of radiation to any astronauts in space at the time.

The players

Patricia Reiff

A professor of physics and astronomy at Rice University in Houston, Texas, with over 50 years of experience studying space plasma physics and analyzing data from the Apollo missions.

Artemis II

NASA's upcoming crewed mission to fly around the moon, the first such mission since the Apollo era.

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What they’re saying

“Space weather comes in several flavors. A solar flare can emit very energetic particles that come at nearly the speed of light, and those are ones that can harm astronauts on their way to the moon because they're so energetic that they can penetrate the hulls of spacecraft.”

— Patricia Reiff, Professor of Physics and Astronomy

“It's kind of like taking a chest X-Ray every day. You don't want to do it for too long.”

— Patricia Reiff, Professor of Physics and Astronomy

What’s next

NASA will continue to closely monitor the sun's activity and space weather conditions as the Artemis II launch date approaches, to ensure the astronauts' safety.

The takeaway

The Artemis II mission will provide valuable data on how deep space radiation affects the human body, which is crucial for planning future long-duration missions to the moon and Mars. While the sun's current peak of activity poses some risks, the stronger solar wind may actually make this an optimal time to launch the mission.