Aster › Space program › Nereid
Nereid
Position on the route: 73/130 · level needed 250 · journey (Mk0 engine) 50.1 h
By the numbers
| Diameter | ≈ 340 km |
|---|---|
| Year | 360 days |
| Distance | 1.4–9.7 million km |
| Found | 1949, Kuiper |
The story
Nereid is Neptune’s third-largest moon and holds the most eccentric orbit of any known moon: eccentricity 0.75; it comes as close as 1.4 million km from Neptune and goes as far as 9.7 million km, taking 360 days a lap. Gerard Kuiper found it in 1949.
That odd orbit is a trace of Triton’s capture: as Triton entered Neptune’s system it smashed or scattered most of the original moons and Nereid was flung to the edge. Its surface contains water ice; Voyager 2 (1989) saw it from only 4.7 million km, as a few pixels.
Missions
- Voyager 2 (1989): a distant image
- A candidate target for planned Neptune missions
Colony note
Remote, with a changing distance; an outpost for ice.
What probes bring back
- The most eccentric orbit of any known moon (e ≈ 0.75): it swings between 1.4 and 9.7 million km from Neptune, with a 360-day year.
- Found by Kuiper in 1949; ≈340 km. It may have been scattered when Triton was captured.