# Carruthers Geocorona Observatory

*Spacecraft*

Photographs the Earth's own outermost air. Above the atmosphere there is a thin halo of hydrogen, the geocorona, reaching far past the Moon and glowing faintly in ultraviolet; from L1 the whole of it fits in one frame, which is not true from anywhere nearer. It is named after George Carruthers, who put the first telescope on the Moon in 1972 and took the picture that showed the halo was there.

| | |
| --- | --- |
| Agency | NASA |
| Launched | 2025-09-24 - still working |
| From the Sun | 149,265,237 km (-45,150 km/d) |
| From the Earth | 1,664,590 km (+3,756 km/d) |
| A signal takes | 6 s |
| Travelling at | 29.4 km/s |

Distances and speed are computed from JPL Horizons trajectories and are true of 2026-09-05, changing at the rate given beside each. The interpolation itself is good to a few kilometres; what ages these figures is the date, not the arithmetic.

## Path

The smallest of the three at L1, and on the same kind of loop. It is pointed back at the Earth rather than at the Sun, which costs it nothing in where it flies - the balance point is chosen for the steady view, and what the view is of is a matter for the instrument.

## Elsewhere

- On the live map: https://www.orbitalmap.space/?world=solar-system&focus=carruthers
- The mission's own page: https://science.nasa.gov/mission/carruthers-geocorona-observatory/
- This object as a page: https://www.orbitalmap.space/o/carruthers/
- Every object: https://www.orbitalmap.space/o/
- What this site is and what it reads: https://www.orbitalmap.space/llms.txt