STEREO-A is a man-made spacecraft represented in the Solar System, the region of space around the Sun, our star, within the universe. Its catalogue reference body is Sun. Explore its story and purpose, then find the spacecraft on the interactive 3D space map.

STEREO-A observes solar activity and material flowing from the Sun.

Mission and scientific objectives
STEREO-A is associated with NASA. STEREO-A observes solar activity and material flowing from the Sun. The mission type is Solar observatory.

Solar TErrestrial RElations Observatory

NASA’s STEREO mission launched in 2006 with two nearly identical observatories — one ahead of Earth in its orbit, the other trailing behind — to study the Sun and obtain stereoscopic observations revealing the 3D structure of the Sun’s largest outbursts called coronal mass ejections. The STEREO-A spacecraft continues to study the Sun to this day and is a key source of unique space weather information.

The STEREO mission studies the structure and evolution of solar storms as they emerge from the Sun.

NASA’s STEREO mission launched in 2006 with two spacecraft to study the Sun, its constant outflow of material called the solar wind, and space weather from multiple points of view.

The mission's two spacecraft, known as STEREO-A (for “Ahead”) and STEREO-B (for “Behind”), orbit the Sun, each drifting relative to Earth (by about 20 degrees per year), with STEREO-A having a slightly faster orbit and STEREO-B slightly slower.

The STEREO-B spacecraft has not returned data since 2014 and was decommissioned in 2018. However, the STEREO mission continues to benefit from the unique vantage point of STEREO-A in combination with other spacecraft observing the Sun and heliosphere. Data from STEREO-A is also used to forecast space weather near Earth and throughout the solar system.

Some of STEREO’s major achievements include:

Current images of the Sun and its surroundings

Images, movies, illustrations, visualizations, and more

STEREO Scientific Visualizations

Visualizations, animations, and more from NASA's Scientific Visualization Studio

STEREO Solar Wind & Particle Plots

Real-time data used for space weather forecasting

Current location of the STEREO spacecraft

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