NASA’s Carruthers Geocorona Observatory has captured its first images from space, revealing rare views of Earth and the Moon in ultraviolet light. Taken on Nov. 17 — still months before the mission’s science phase begins — these “first light” images confirm the spacecraft is healthy while hinting at the incredible views to come.
The initial images consist of two from Carruthers’ Wide Field Imager and two from its Narrow Field Imager. Each imager captured two different views: one showing a broad spectrum of far ultraviolet light, and one revealing light from Earth’s geocorona.
When Carruthers captured these images, the Moon was also in its field of view and slightly closer to the spacecraft than Earth was, making the Moon appear larger and closer to Earth than usual.
The specific wavelength Carruthers observed in two of the images, called Lyman-alpha, is light emitted by atomic hydrogen. The faint glow of Lyman-alpha from hydrogen in Earth’s outer atmosphere is called the “geocorona,” Latin for “Earth crown.”
In the broad-spectrum images, the Moon and Earth look similar: both are spheres with well-defined edges. However, in the Lyman-alpha filter, the Moon still appears as a crisp, sharp sphere while Earth appears surrounded by a bright “fuzz” extending out to space. This glow is the geocorona, the primary focus of the Carruthers mission. It is the only way to “see” Earth’s outermost atmospheric layer, although the light of the geocorona has only been photographed a handful of times in history. Carruthers will be the first mission to image it repeatedly, and from far enough away to see its great extent and discover how it changes over time.
These first images also offer a rare treat: sunlight reflected off the far side of the Moon, a view impossible to capture from Earth.
These initial images were taken with short, five-minute exposures — just long enough to confirm that the instrument is performing well. During the main science phase, Carruthers will take 30-minute exposures, allowing it to reveal even fainter details of the geocorona and trace how Earth’s outer atmosphere responds to the changing Sun.
Carruthers launched on Sept. 24 and is just a few weeks from completing its journey to the Sun-Earth Lagrange point 1, a point of gravitational balance roughly 1 million miles closer to the Sun than Earth is. Carruthers will begin its primary science phase in March 2026, when it will begin sending back a steady stream of ultraviolet portraits of our planet’s ever-shifting outer atmosphere.
By Miles Hatfield
NASA’s Goddard Space Flight Center, Greenbelt, Md.
