Skip to content
You can now search across every topic, entity and event.What's new
Space weather
Concept

Space weather

Solar-driven radiation hazard threatening Artemis II beyond Earth's magnetosphere.

Last refreshed: 3 April 2026

Key Question

How does space weather threaten the Artemis II crew?

Timeline for Space weather

#910 Apr

Mentioned in: G1 to G2 storming on Orion re-entry day

Artemis II Moon Mission
#57 Apr

Mentioned in: Crew Observes Solar Eclipse From Beyond Moon

Artemis II Moon Mission
#56 Apr

Space Weather Clears for the Flyby Window

Artemis II Moon Mission
#131 Mar

Created active conditions with X-class flare on 31 March and G1 watch

Artemis II Moon Mission: Solar Flare Creates Radiation Risk During Moon Burn Window
View full timeline →
Common Questions
Is the Artemis II crew in danger from solar radiation?
An X-class flare and G1 storm watch coincided with the translunar burn window, but Orion has a storm shelter and real-time dose monitoring.Source: Lowdown briefing coverage
What is an X-class solar flare?
The most intense category of solar flare, capable of disrupting communications and posing radiation risk to astronauts.Source: NOAA space weather scale
When were humans last outside Earth's magnetic field?
Apollo 17 in December 1972, 54 years before Artemis II.Source: NASA mission records

Background

An X-class solar flare on 31 March 2026 and a G1 geomagnetic watch through 2 April created active Space weather conditions during the Artemis II translunar injection burn window. The crew will pass beyond Earth's magnetosphere for the first time in 54 years, exposing them to unshielded solar particle radiation.

Space weather refers to solar-driven disturbances (flares, coronal mass ejections, geomagnetic storms) that affect spacecraft, communications, and human health in space. The Space Weather Prediction Center (SWPC), a division of NOAA, issues forecasts that NASA uses for crew safety decisions. Orion carries the Hybrid Electronic Radiation Assessor (HERA) to monitor dose rates in real time.

For Artemis II, Space weather is not a background concern but an operational constraint. A severe solar particle event during cislunar transit could force the crew into Orion's storm shelter, delay EVA timelines on future missions, and reshape NASA's risk calculus for Artemis III's planned lunar surface operations.