To begin, Triton is considered to be one of the coldest places in our entire Solar System. The moon’s surface temperature is about -235°C on average, while Pluto averages about -229°C.

Triton is a world of extremes. It’s by far the largest moon of Neptune, with a radius of 1,350 kilometers, or just 22% smaller than Earth’s moon.

There are many good arguments for why we should revisit Neptune's moon, three decades after Voyager 2 flew past. Triton has many peculiarities, including the fact it did not form around Neptune.

Triton could be particularly useful due to very unusual behavior. It orbits in the opposite of Neptune’s direction. Its ionosphere is 10 times more active than any other moon in the system.

NASA’s Cassini probe found signatures consistent with microbial life on Titan (one of Saturn’s moon). The main candidates for life in the solar system have been Mars, Titan and Europa. Triton and ...