Triton is the largest natural satellite of Neptune and it is of significant interest in the aerospace context because of its unique geology, atmosphere and potential for having a subsurface ocean.
Triton is a cold, icy body with a surface temperature of about 38K (-235C). Its surface is covered in frozen nitrogen, methane, and carbon dioxide ices, and it has a tenuous atmosphere. Triton has a retrograde orbit, meaning it orbits Neptune in the opposite direction of the planet's rotation, this suggests that Triton was once a independent object that was captured by Neptune's gravity.
In the aerospace context, Triton has only been explored by one spacecraft, the Voyager 2 which flew by Triton in 1989. The Voyager 2 provided the first detailed images of Triton's surface and data on its geology, geophysics, and atmosphere. The data revealed Triton's unique geology, including its ice volcanoes, which are believed to be formed by the cryovolcanism or the eruption of water, ammonia, or methane. There are also a number of possible indications of a subsurface ocean, including its density, which is similar to that of a water-ice body, and the presence of fractures on its surface that resemble those seen on Earth's ice shelves.
Triton's atmosphere is also of interest because it is one of the coldest known in the solar system, and because it is losing atmosphere to space due to its low gravity and the solar wind. This makes Triton an interesting object to study the processes of atmospheric loss and escape.
Triton's unique characteristics make it a prime target for future missions, such as the study of its subsurface ocean, the geology of its icy surface and the study of its atmosphere.