Radiation Environments
The particle-radiation hazards of space — the Van Allen belts, galactic cosmic rays, and solar energetic particles.
- Cosmic RaysRadiation environment
High-energy charged particles that stream through space near the speed of light. They come from the Sun (solar energetic particles) and from beyond the Solar System (galactic cosmic rays), and are a primary radiation hazard for astronauts.
- Galactic Cosmic Rays (GCR)Radiation environment
Extremely energetic charged particles from outside the Solar System — the remnants of supernovae and other violent events. They pervade deep space, are hard to shield against, and pose the dominant long-term radiation risk on missions to Mars.
- Solar Energetic Particles (SEP)Radiation environment
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.
- Van Allen Radiation BeltsRadiation environment
Two (sometimes more) doughnut-shaped zones of energetic charged particles trapped by Earth's magnetic field. Spacecraft crossing the belts — and those in orbits within them — must be hardened against the intense radiation.