Aster › Space program › Callisto
Callisto
Position on the route: 15/45 · level needed 84 · journey (Mk0 engine) 16.4 h
By the numbers
| Diameter | 4,821 km |
|---|---|
| Gravity | 1.24 m/s² |
| Orbit | 16.7 days |
| Surface age | ≈ 4 billion years |
| Radiation | low |
The story
The most heavily cratered surface in the Solar System, almost unchanged for four billion years. Being the farthest large moon from Jupiter, its radiation is low, which is why it is considered the best candidate for a crewed base in the Jupiter system.
The surface is ice and dark rock, and a salty ocean may lie underneath. A mixture of rock and ice means both water and building material.
Missions
- Voyager 1 and 2 (1979): a map of the craters
- Galileo (1995–2003): close flybys
- JUICE (ESA): after 2031
Colony note
The safest base of the Jupiter system: low radiation, ice aplenty. No shield needed.
What probes bring back
- The most heavily cratered surface in the Solar System: almost unchanged for 4 billion years.
- Far from Jupiter: radiation is low, so it is seen as the best candidate for a crewed base.