Aster › Space program › Dactyl
Dactyl
Position on the route: 23/130 · level needed 63 · journey (Mk0 engine) 10.4 h
By the numbers
| Diameter | ≈ 1.4 km |
|---|---|
| Distance | ≈ 90 km |
| Found | 1994, Galileo |
| Primary | 243 Ida |
The story
Dactyl is Ida’s small moon, about 1.4 km across, and the first moon found around an asteroid. When Galileo’s 1993 images were studied in 1994, Ann Harch spotted it. It is named for the Dactyls who lived on Cybele’s Mount Ida.
Its discovery showed that asteroids can carry moons. It circles Ida at about 90 km; its surface is cratered and about as old as its parent.
Missions
- Galileo (NASA, 1993): the discovery images
Colony note
Tiny; observation only.
What probes bring back
- Ida’s moon, about 1.4 km across, circling roughly 90 km away; the first asteroid moon found, in Galileo images.
- The find proved that asteroids can carry moons; hundreds of binary asteroids are known today.