A new proposed mission under NASA’s discovery program is aiming to fly by Triton, the largest moon of planet Neptune in less than two decades. This mission will facilitate a deeper understanding of the ocean worlds of our solar system. As much as we love regularities and similar behaviour, oddities attract us. Triton is one such catch. In 1846, when astronomer William Lassel assembled his telescope, he had no idea that he was moments away from discovering the divergent satellite of our solar system.
Why Triton is so Special?!
Triton is about 1.3 times smaller than our moon. This is the only moon that orbits in a direction opposite to the rotation of its host planet in an eccentric orbit tilted at 23 degrees from Neptune’s equator. It is a frozen world of nitrogen having an ionosphere which contains charged particles. This ionosphere is said to be 10 times more active than any other moons, even though Neptune is very far from the sun. But how do we know this? In 1989, Voyager 2 spacecraft flew by Triton capturing jaw-dropping close-up images which caused a stir. Astronomers almost lost it but were determined to extract every possible information.
Triton has a young and smooth surface with the occasional eruption of icy volcanoes and gigantic dark plumes of glacial material. It also has an uncertain and lively climate with a substantial snowing of organic materials like nitrogen. Furthermore, it is said that Triton was a former Kuiper Belt object that was bagged by Neptune’s gravity a long time ago making it the closest observable outer space object. So far, we have no idea what drives the plumes or keeps the ionosphere active as the Sun is very far. (Neptune is almost thirty times far from the sun than the earth) Is Triton an Ocean world? Does it have a relatively warm interior? What causes the surface to refresh now and then? Why the activity?
Trident to meet Triton
Buckle up your seat belts, because we are going back to Triton to find answers. A mission named Trident is battling with three other missions under concept study missions by NASA, among which two are likely to be selected and launched. Trident ( yes like the spear of Neptune, the God of the sea) will be flying by Triton to get its hand on every available data with respect to the moon.
Trident aspires to access Triton in a three-pronged manner. Its first major goal is to reason out the cause of the self-driven plumes. Plumes are not a new sight. They are observed on Enceladus and probably on Europa, the respective moons of Saturn and Jupiter and It is believed that these are formed when interior water pushes through thick, icy crusts. Trident would use specialized instruments to observe the magnetic field of Triton to ascertain the presence of oceans inside. And if it turns out favourable, astronomers would fly high as it would give them fresh information regarding the formation of ocean worlds. It would also widen our knowledge about where to find water. And since the presence of water is a factor determining the habitability of an external world, this information would shed more light on the subject which is one of Triton’s major goals.
Another goal of Trident is to explore the vast unknown lands. Triton has the strangest untouched solid surface observable from this side of the Kuiper belt. Trident would map the moon thoroughly and would also use full-frame imaging to take photographs of the same plume filled area captured by voyager 2. This way we can compare and study the changes in Triton and know more about its activity. Triton has a relatively young surface which is only about ten million years old. This weird surface refreshes itself with raw material every now and then and also looks offbeat without any craters. Therefore the third major goal of Trident would be to uncover the reason behind these phenomena. All these answers will give us information about surface development in icy bodies.
Mission Trident would be led by Louise Prockter, the Director of Lunar Planetary Institute(LPI). The proposed launch date is in October 2025. From then on, the spacecraft would fly for 13 years and have a 13 day meet up with Triton in 2038. The launch date is chosen considering the Earth-Jupiter alignment which will provide an initial push. Trident will be managed by NASA’s Jet Propulsion Laboratory (JPL) in California, Mission Trident is worth the wait as it will reveal a lot more than we expect.
Reference: NASA
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