Strategic Science Areas (SSAs)

Foundational research themes that guide Living With a Star investigations into Sun-Earth connections.

View SSA Descriptions
Strategic Science Areas

Comprehensive research themes addressing critical aspects of the Sun-Earth system

SSA-I: Origins and Variability of Global Solar Processes

Key Elements: Solar Cycle, Dynamo, Irradiance, Solar Wind

(revised from original SSA-0, Solar Electromagnetic, Energetic Particle, and Plasma Outputs)

SSA-II: Solar Eruptive and Transient Heliospheric Phenomena

Key Elements: Flares, Coronal Mass Ejections, Corotating Interaction Regions

(extracted from numerous original SSAs)

SSA-III: Acceleration and Transport of Energetic Particles in the Heliosphere

Key Elements: Particle Injection, Shocks, Radiation Hazards, Heliospheric Field Structure

(revised from original SSA-3, Solar Energetic Particle Forecasting)

SSA-IV: Variability of the Geomagnetic Environment

Key Elements: Geomagnetically Induced Currents (GIC), Geomagnetic Storms, Substorms

(revised from original SSA-1, Geomagnetic Variability Forecasting)

SSA-V: Dynamics of the Global Ionosphere and Plasmasphere

Key Elements: Electron Density Profile, Total Electron Content, Storm Time Dynamics, Traveling Ionospheric Disturbances, Plasmasphere Refilling

(revised from original SSA-4, TEC Forecasting)

SSA-VI: Ionospheric Irregularities

Key Elements: Scintillation, Polar Cap Absorption, Plasma Instabilities, Radio Wave Propagation

(revised from original SSA-5, Ionospheric Scintillation Forecasting)

SSA-VII: Composition and Energetics of the Neutral Upper Atmosphere

Key Elements: Atmospheric Drag, Heating and Cooling, Waves and Tides

(revised from original SSA-2, Satellite Drag Forecasting)

SSA-VIII: Radiation and Particle Environment from Near Earth to Deep Space

Key Elements: Radiation Damage, Human Exposure, Spacecraft Charging, Radiation Belts, Plasma Sheet, Heliospheric Energetic Particles

(revised from original SSA-6, Radiation Environment Forecasting; extended to deep space)

SSA-IX: Solar Impacts on Climate

Key Elements: Solar Irradiance, Energetic Particle Precipitation, Coupled Chemical and Dynamical Response of Atmosphere, Ozone Layer

(revised from original Sun-Climate Theme – was formerly separate from SSAs)

SSA-X: Stellar Impacts on Planetary Habitability

Key Elements: Atmospheric Depletion and Stripping, Magnetospheric Shielding, Stellar Winds, Flares and Mass Ejections

(new topic)