NASA’s Carruthers Observatory Begins Mission to Study Earth’s Hydrogen Halo

On March 1, 2026, NASA's Carruthers Observatory has started its two-year science mission. It studies Earth's exosphere, the outermost layer of the atmosphere, rich in hydrogen (seen as an ultraviolet “geocorona”). From its Sun–Earth L1 orbit about 1 million miles from Earth, it continuously images the geocorona's glow. These observations will help scientists understand how the upper atmosphere responds to space weather events from the Sun.

Mission Status and Observations

According to information provided by NASA, Carruthers was launched in September 2025. It has reached its halo orbit around the Sun-Earth L1 point as of January 2026. Carruthers has been equipped with two ultraviolet cameras to take pictures of the hydrogen geocorona. With the aid of Carruthers, the expansion and contraction of the hydrogen halo around the exosphere can be studied over a period of two years. This provides information on how the upper atmosphere of the Earth responds to solar storms and fast streams of solar wind.

Mission Goals and Team

The Carruthers observatory is a small satellite developed by BAE Systems, with the University of Illinois Urbana-Champaign leading the way. It is equipped with two UV cameras and is the first satellite designed to explore the exosphere around the Earth. It has the support of the University of California at Berkeley and Utah State University (for payload development) and NASA's Goddard Space Flight Center (for mission management). It is named after a scientist from the Apollo program who worked during the 1960s: George Carruthers. It will help answer some fundamental questions about the size of the hydrogen halo and how the Earth and Mars lose water into space.