When the space environment around Earth changes dramatically it is called space weather. Much as the monitoring and forecasting of terrestrial weather has improved over the last century, scientists now work to improve our understanding of space weather, because – when extreme – space weather can affect a wide variety of modern technologies, from radio waves that travel through near-Earth space to GPS satellites to the computer electronics on board spacecraft.
NASA seeks to better understand how energy and material from the sun drives space weather near Earth. The potential effects of severe space weather are wide ranging:
- Magnetic storms can interfere with high-frequency radio communications and GPS navigation.
- Radio communications can be compromised at the poles – an issue for airliners on transpolar routes.
- Magnetic storms can cause strong electrical currents in power grids, disrupting utility services.
- Such electric currents can also appear in oil and gas pipelines, causing early corrosion.
- Harsh space weather radiation can pose risks for astronauts.
- Space weather radiation can damage spacecraft solar arrays and interfere with communications.
- Fast-moving particles from space weather events can trip onboard satellite electronics.
- Changes in near-Earth space can expose certain satellites to more drag than expected, causing pre-mature orbital decay.
NASA heliophysics works is the research arm of the nation's space weather effort, coordinating with the U.S. National Oceanic and Atmospheric Administration, the National Science Foundation and the U.S. Geological Survey, and the U.S. Air Force Research Laboratory on the National Space Weather Action Plan. Researching space weather is a complex task because of the intricate interactions between many systems: the sun, the solar wind, Earth's magnetic field, and Earth's atmosphere. NASA heliophysics employs a diverse fleet of spacecraft to observe these systems. It also supports improvements in space weather prediction models, such as those used by NOAA's Space Weather Prediction Center, the U.S. government's official source for space weather forecasts.
NASA observes space weather processes with such missions as: the Advanced Composition Explorer and NOAA's Deep Space Climate Observatory, which observes the solar wind; the Solar Dynamics Observatory, the Solar and Terrestrial Relations Observatory, the joint ESA/NASA Solar and Heliospheric Observatory, which can all observe solar eruptions on the sun; and the Van Allen Probes, which observes the radiation belts around Earth.