Artemis II NASA astronauts (left to right) Reid Wiseman, Victor Glover, and Christina Koch, and CSA (Canadian Space Agency) astronaut Jeremy Hansen will spend time outside of Earth’s naturally occurring protective magnetic shield. Periods of heightened solar activity during the mission could pose significant radiation risks to the crew. [Photo credit: NASA]
The Artemis II mission is planned as a 10-day crewed flight around the moon and back to Earth, marking a historic return of humans to lunar orbit for the first time since Apollo 17 in 1972. As NASA prepares to send astronauts beyond low Earth orbit, Artemis II represents more than a symbolic milestone—it is a concrete step toward sustained human presence beyond Earth, with the moon serving as a proving ground for future interplanetary travel.
NOAA’s long-standing role in environmental monitoring provides a clear model for how space weather services could evolve for the future. Just as NOAA protects mariners and aviators by tracking hazardous conditions on Earth, missions like Artemis II underscore the importance of extending that capability outward, ensuring that human explorers are informed and protected as they venture farther into the solar system, beginning with the moon and eventually Mars.
Human exploration beyond Earth’s immediate environment introduces unique risks that differ fundamentally from those in low Earth orbit. Among the most significant is exposure to space weather, particularly solar radiation driven by solar flares and coronal mass ejections (CMEs). Monitoring and understanding these hazards is an area where NOAA plays a critical role through its space weather satellite programs and 24/7 forecasting mission.
A key factor in assessing astronaut risk during the Artemis II mission is the relationship between the moon and Earth’s magnetosphere. This magnetic field forms a large, protective bubble that shields Earth from much of the sun’s harmful charged particle radiation. This protective region extends well beyond Earth itself and, for approximately three to six days during the moon’s 28-day orbit), the moon passes through Earth’s magnetotail–a long, comet-like extension of Earth's magnetic field, stretched away from the sun by the solar wind. While radiation exposure is not eliminated entirely, this region significantly reduces the exposure to solar radiation for objects in the tail.
A diagram illustrating the moon’s orbit in relation to Earth’s magnetic field and magnetotail. The magnetotail extends away from the sun like a long, comet-shaped stream, formed by the solar wind. As it orbits Earth, the moon periodically passes through this region. Earth and the moon are not shown to scale. [Credit: NOAA]
For the majority of its orbit, the moon remains outside Earth’s magnetic field and is directly exposed to the full force of the solar wind and energetic solar particles. Artemis II astronauts will therefore spend time outside this naturally occurring protective shield. Any overlap between periods of heightened solar activity and time spent beyond Earth’s magnetospheric protection could pose significant radiation risks to the crew.
NASA relies on operational space weather forecasts and warnings from NOAA’s Space Weather Prediction Center (SWPC). As the nation’s official around-the-clock space weather forecasting authority, SWPC provides direct, real-time support to human spaceflight missions. Observations from NOAA’s GOES satellites and the SOLAR-1 observatory at Lagrange point 1 will provide important measurements of solar wind speed, magnetic field orientation, and the flow of hazardous, high-energy particles. These observations allow SWPC to issue timely warnings if radiation levels approach thresholds that could affect astronaut safety. During the Artemis II mission, NOAA forecasters will continuously monitor solar wind conditions and evaluate any solar flares, coronal mass ejections (CMEs), or solar energetic particle events that may occur.
The Solar Ultraviolet Imager (SUVI), Extreme Ultraviolet and X-Ray Irradiance Sensors (EXIS), Space Environment In-Situ Suite (SEISS), and Magnetometer (MAG) are specialized instruments onboard the GOES-R Series satellites that measure solar activity and changes in Earth's magnetic field. Additionally, the Compact Coronagraph (CCOR-1) onboard GOES-19 further enhances the detection of CMEs by providing continuous real-time monitoring of the sun’s corona, improving both measurement quality and warning lead time.
The SOLAR-1 observatory at Lagrange point 1 is going to extend this full-time observational capability upstream, from a vantage point closer to the sun. It will combine continuous imagery taken from the compact coronagraph (CCOR-2), a near identical instrument to the CCOR-1 on GOES-19, with directly collected solar wind and magnetic field measurements from its Solar Wind Plasma Sensor (SWiPS), SupraThermal Ion Sensor (STIS) and Magnetometer (MAG). These real-time observations will provide earlier detection of space weather disturbances that can impact Earth, and will drive the models used routinely to understand and predict the extent and intensity of solar activity and its effects on the Earth’s environment.
A diagram showing the trajectory for NASA’s Artemis II test flight. [Credit: NASA.]
Artemis II launched at 6:35 p.m. EST on April 1, 2026 carrying four astronauts on a free-return trajectory around the moon. The mission will test life support, navigation, and deep space operational systems in preparation for future lunar surface missions.
As human spaceflight expands beyond government-led exploration toward a future that includes commercial and international partners, the need for reliable space weather services will only grow. Artemis II highlights the reality that astronauts venturing beyond Earth’s magnetic protection face hazards that must be monitored, forecast, and communicated with the same rigor applied to weather hazards on Earth.