2.5 Making plans for Titan
In the video Titan is referred to as the only moon with an atmosphere. In fact, the truth is that Titan is the only moon with a dense atmosphere. Neptune’s largest moon, Triton, also has an appreciable atmosphere. Triton is smaller than the Galilean moons of Jupiter, but with a surface temperature of only −235 °C it has been able to retain a thin atmosphere of 99% nitrogen plus traces of methane and carbon monoxide, with a surface pressure about one-fifty-thousandth of Earth’s (0.02 millibars or about 20 microbars). This may be miniscule, but it is enough to form clouds of tiny nitrogen-ice crystals at heights of a few kilometres, analogous to Earth’s cirrus clouds, which are made of tiny crystals of water-ice.
The Titan Mare Explorer (TiME) referred to near the end of the video was short-listed for development by NASA, but was dropped in favour of a Mars mission in 2012. However in 2019 a different mission concept called Dragonfly was approved. To find out about that, visit the link at the end of this section.
Use the downloadable table to compare some of the characteristics of Titan and Triton.
See also: The dragonfly mission to Titan. Description and a brief animation about a “rotorcraft” (helicopter) for 2026 launch and 2034 arrival.