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NASA’s Carruthers Geocorona Observatory Reaches Target Orbit

NASA’s Carruthers Geocorona Observatory has achieved its target orbit, positioning the spacecraft to capture the first repeated observations of the ultraviolet glow from Earth’s outer atmosphere, the geocorona.

The achievement was confirmed following its third and final orbital maneuver, a 2-minute thruster fire, on Jan. 8. The spacecraft has now entered its intended halo orbit around the Sun-Earth L1 Lagrange point, a position of gravitational balance approximately 1 million miles from Earth.

A spacecraft with large solar panels floats in the foreground of space, with a view of distant Earth and the Moon against a backdrop of stars.
An artist’s concept shows the Carruthers Geocorona Observatory at Earth–Sun Lagrange point 1 (L1).
NASA’s Conceptual Imaging Lab/Jonathan North

The loveseat-sized spacecraft launched from NASA’s Kennedy Space Center on Sept. 24, 2025. Since launch, the Carruthers team has been testing the spacecraft’s instruments, capturing its “first light” images, and adjusting its course as it approached L1. Carruthers now begins its final checkout procedures before beginning its two-year primary science mission in March.

Comparison of wide field and narrow field space imaging: Each column shows far ultraviolet and Lyman-alpha views of Earth, with brightness color scales, using wide and narrow field imagers.
These four images constitute the “first light” for the Carruthers Geocorona Observatory mission. The images were taken on Nov. 17, 2025, from a location near the Sun-Earth Lagrange point 1 by the spacecraft’s Wide Field Imager (left column) and Narrow Field Imager (right column) in far ultraviolet light (top row) and the specific wavelength of light emitted by atomic hydrogen known as Lyman-alpha (bottom row). Earth is the larger, bright circle near the middle of each image; the Moon is the smaller circle below and to the left of it. The fuzzy “halo” around Earth in the images in the bottom row is the geocorona: the ultraviolet light emitted by Earth’s exosphere, or outermost atmospheric layer. The lunar surface still shines in Lyman-alpha because its rocky surface reflects all wavelengths of sunlight — one reason it is important to compare Lyman-alpha images with the broad ultraviolet filter. The far ultraviolet light imagery from the Narrow Field Imagery also captured two background stars, whose surface temperatures must be approximately twice as hot as the our Sun’s to be so bright in this wavelength of light.
NASA/Carruthers Geocorona Observatory

Carruthers uses two cameras, a wide-field imager and a narrow-field imager, to capture the most detailed images ever taken of Earth’s geocorona, the glow of ultraviolet light emitted by Earth’s outermost atmospheric layer. The mission was named in honor of Dr. George R. Carruthers, inventor of the ultraviolet camera placed on the Moon by Apollo 16 astronauts that captured the first images of Earth’s geocorona in 1972.

The Carruthers Geocorona Observatory mission is led by Dr. Lara Waldrop from the University of Illinois Urbana-Champaign. The Space Sciences Laboratory at the University of California, Berkeley, leads mission implementation and operations, design, and development of the payload in collaboration with Utah State University’s Space Dynamics Laboratory. The Carruthers spacecraft was designed and built by BAE Systems. NASA’s Explorers and Heliophysics Projects Division at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, manages the mission for the agency’s Heliophysics Division at NASA Headquarters in Washington.

By Miles Hatfield
NASA’s Goddard Space Flight Center, Greenbelt, Md.