Their era of mere flybys of the outer solar planets is ending. Orbiters of Jupiter and Saturn are now on station. Orbiters of Uranus and Neptune have been proposed though unlikely to receive funding in the near future. But a probe dedicated to exploring the Kuiper belt has already taken a closer look at Pluto.

Enough has been learned about the moons of the outer planets in early flybys of the planets to keep scientists so intrigued that dedicated missions to the most promising for harbouring life are in the development stage. Here is what is known about these enigmatic moons and why they merit extended visits.