Aster › Space program › Helene
Helene
Position on the route: 53/130 · level needed 131 · journey (Mk0 engine) 24.6 h
By the numbers
| Size | ≈ 36 × 32 × 30 km |
|---|---|
| Year | 2.74 days |
| Distance | 377,400 km |
| Found | 1980 |
The story
Helene is a ‘Trojan’ moon of Saturn’s large moon Dione: it circles 60° ahead of Dione on its orbit (the L4 point). Pierre Laques and Jean Lecacheux found it from the ground in 1980. About 33 km, icy and cratered.
Cassini’s images showed an unexpected smoothness on its surface: craters partly filled in, and flows of dust and ice sliding down slopes.
Missions
- Cassini (2004–2017): close images
Colony note
With Dione; an outpost for ice.
What probes bring back
- A ‘Trojan’ moon of Dione: it circles 60° ahead (L4). About 33 km.
- Cassini’s images show smooth terrain made by flows of dust and ice.