Active, surveying the exosphere. Dates per NASA; missions shift.
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What is it? A space An instrument that collects light (or other energy) to see faraway things more clearly. Glossary surveying Earth's exosphere in ultraviolet light.
Why does it matter? To chart changes in the exosphere, the transition from Earth's environment to space.
NASA's Carruthers Geocorona Observatory launched on September 24, 2025 and studies the geocorona, the ultraviolet glow of Earth's exosphere, our planet's outermost atmospheric layer. It is the first mission dedicated to charting changes in this region, which is hard to observe from the ground. It is named after Dr. George R. Carruthers, whose telescope took the first images of the geocorona from the Moon on Apollo 16 in 1972.
Earth wears a faint ultraviolet halo, the geocorona, first photographed from the Moon by Apollo 16 in 1972; NASA's Carruthers mission now charts it from a million miles away.
Want to go deeper? NASA, Carruthers Geocorona Observatory has the full story and the latest updates.