Skip to content
AsteriaStar
Radiation environment

Solar Energetic Particles (SEP)

Bursts of high-energy particles accelerated by solar flares and coronal mass ejections. Unlike the steady galactic cosmic rays, SEP events are sudden and can deliver a dangerous radiation dose to astronauts within hours.

Knowledge connections

Sources

The primary and reference sources this topic draws on.

  • NASANational Aeronautics and Space Administration

    Mission data, planetary science, space telescopes, and public-domain imagery.

    Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.

  • NOAA Solar CalculatorNOAA Global Monitoring Laboratory

    Public-domain solar-position geometry: sunrise, sunset, solar noon, twilight, declination, and the equation of time.

    Public domain (US Government work).