Aster › Space program › Ganymede
Ganymede
Position on the route: 13/45 · level needed 82 · journey (Mk0 engine) 16.4 h
By the numbers
| Diameter | 5,268 km |
|---|---|
| Gravity | 1.43 m/s² |
| Orbit | 7.15 days |
| Structure | ice crust, salty ocean, rocky core |
| Magnetic field | yes (the only moon with one) |
The story
The largest moon in the Solar System, bigger than Mercury. It has its own magnetic field (Galileo 1996), which points to a liquid iron core. A layered salty ocean is thought to lie beneath the ice crust.
The field partly shields the surface from Jupiter’s radiation, more so at the poles, which is why Ganymede’s poles are considered for a crewed base. JUICE (launched 2023) reaches Jupiter in 2031 and enters Ganymede orbit in 2034.
Missions
- Pioneer 10/11 and Voyager: the first close images
- Galileo (1996): discovery of the magnetic field
- JUICE (ESA, Jupiter 2031, Ganymede 2034)
Colony note
Plenty of ice; a Mk1 shield. Less radiation at the poles; a hub for the Jupiter system.
What probes bring back
- The largest moon in the Solar System (5,268 km) and the only one with its own magnetic field.
- A salty ocean lies under the ice crust; JUICE (launched 2023) enters orbit in 2034.