Understanding the Space Environment
The hazards of space — the Sun's storms, the radiation of the Solar System and galaxy, and the debris and plasma that threaten spacecraft and astronauts — and the missions that watch for them. Built on real NASA and NOAA data; this encyclopedia states no live conditions and nothing is fabricated.
In pictures
- 1.1What is space weather?Space is not empty — it is full of radiation, plasma, and debris.
- 1.2The solar windThe Sun's constant outflow that fills the Solar System.
- 1.3Solar flares and CMEsThe eruptions that drive the biggest storms at Earth.
- 1.4Geomagnetic storms and aurorasHow solar eruptions disturb Earth's magnetic field.
- 3.1Orbital debrisThe growing hazard of human-made junk in Earth orbit.
- 3.2Spacecraft chargingHow the plasma environment can zap electronics.
- 3.3Radiation on the way to MarsThe dominant risk for long-duration human missions.
- 3.4The heliosphere and its edgeThe Sun's bubble, and the boundary the Voyagers crossed.
Related entities
- Space-weather phenomenon
Solar Wind
The continuous stream of charged particles — mostly protons and electrons — that flows outward from the Sun's corona at hundreds of kilometres per second, filling the Solar System and shaping planetary magnetospheres.
- Space-weather phenomenon
Geomagnetic Storm
A temporary disturbance of Earth's magnetosphere, driven by the arrival of a fast solar wind or a coronal mass ejection. Strong storms can disrupt satellites, power grids, and navigation, and drive bright auroras.
- Radiation environment
Van Allen Radiation Belts
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.
- Geomagnetic index
Kp Index
A global index of geomagnetic activity, derived from magnetometer readings and reported every three hours on a scale of 0 (quiet) to 9 (extreme storm). Kp is the standard measure used to forecast auroras and satellite disturbances.