The Carruthers Geocorona Observatory is one of NASA’s newest Earth-facing space weather missions, named in honor of the late George Carruthers, a pioneering astrophysicist who built the first lunar-based telescope as part of the Apollo 16 mission.
Photo: NASA
What Will This Observatory Measure?
The observatory’s mission is to image the geocorona, a vast cloud of hydrogen atoms that extends tens of thousands of miles beyond Earth’s atmosphere. Also called the exosphere, it is invisible to the naked eye. The geocorona’s hydrogen halo interacts with solar radiation and can be measured to monitor how solar activity affects Earth’s environment.
The Carruthers Observatory uses ultraviolet (UV) imaging to observe how the geocorona responds to solar emissions, particularly during solar storms. By watching the movement and intensity of hydrogen glow in the far-UV spectrum, scientists can get early indicators of incoming disturbances from the Sun.
“Carruthers gives us a front-row seat to the very edge of Earth’s atmospheric bubble,” said Nicola Fox, associate administrator for NASA’s Science Mission Directorate. “It’s a critical piece in understanding how Earth responds to solar energy.”
Heading To L1
After launch, the telescope will travel to the L1, or the first Lagrange Point, which is relatively near the Earth — about one million miles away. L1 is the point of gravitational equilibrium between the Earth and the Sun, and that region provides a stable position for small objects to reside while using a minimum amount of fuel to remain there. Several scientific payloads, such as the Solar and Heliospheric Observatory (SOHO) also reside in the region.
Carruthers will be able to directly measure the size of Earth’s geocorona for the first time. The first Carruthers telescope landed on the moon, too close to see the geocorona in its entirety. That said, this mission will enable scientists to measure the size of Earth’s atmosphere for the first time.
The spacecraft is part of the IMAP Rideshare mission, which will launch tomorrow Wednesday.
| Details | |
|---|---|
| Mission | Falcon 9 Block 5 | IMAP & others — Go for Launch! |
| Organization | SpaceX |
| Location | Kennedy Space Center, FL, USA |
| Rocket | Falcon 9 |
| Pad | Launch Complex 39A |
| Status | Go for Launch |
| Status Info | Current T-0 confirmed by official or reliable sources. |
| Window Opens | Wednesday, 09/24/2025 7:30:35 AM |
| Window Closes | Wednesday, 09/24/2025 7:30:35 AM |
| Destination | Heliocentric L1 |
| Mission Description |
IMAP (Interstellar Mapping and Acceleration Probe) is a NASA mission to study interactions between solar wind and the local interstellar medium.
Carrying a suite of 10 scientific instruments, IMAP is able to investigate how particles are accelerated, determine their composition,
as well as help to advance space weather forecasting models.
The IMAP launch also includes the space weather satellite SWFO-L1 (Space Weather Follow-On – L1) for NOAA and the GLIDE (Global Lyman-alpha Imagers of the Dynamic Exosphere/Carruthers Geocorona Observatory) mission to study far ultraviolet emission in the Earth’s exosphere. |
As of 12:22 PM Monday September 22, 2025. Launch times are subject to change or cancellation at any time. Consult SpaceX.com for more information.