Will NASA Return to Neptune?


Scientists from NASA’s Jet Propulsion Laboratory have suggested a new mission along with a spacecraft that would study Neptune’s biggest moon Triton. They announced their idea during the Lunar and Planetary Science Conference in Texas held on Tuesday


Triton is thought to be a strange satellite similar to Pluto in many ways. It comes from the solar system’s icy Kuiper belt captured billions of years ago by Neptune’s gravity. Furthermore, it is believed that Triton is home to an ocean, which means there is a chance that it could host life. 

The proposed mission to Triton strives to be cost-effective. Launching the spacecraft, known as Trident, would cost the same as a small mission to the moon, according to the mission’s scientists and engineers.

Louise Prockter, the director of the Lunar and Planetary Institute in Houston and the chief investigator of the suggested mission, said now is the time to launch this mission at a low cost because it’s imperative to figure out whether Triton is a world that hosts life.

Although costly projects such as the Cassini mission to Saturn or the Europa Clipper spacecraft which is scheduled to launch in the 2020s have generated some major achievements, smaller, less expensive missions could also help with planetary science. For example, on Mars, it was multiple missions over time that uncovered the planet’s past water.

The scientists backing the Trident proposal, which will be officially presented to NASA later in March, are looking to be backed by the agency’s highly competitive Discovery program, which is all about missions that cost under $500 million.

NASA’s goal is to deploy these missions every two years. Most recently, the Discovery mission launched the InSight lander, which landed on Mars this past November. The next mission should be the Lucy mission, which aims to study asteroids that share Jupiter’s orbit around the sun.

Trident must compete with proposals for more extensive studies of the moon, a Jupiter moon mission to Io and a second mission to Venus. However, those who support the Trident mission hope that exploring Neptune, the solar system’s most remote planet at a low-cost will convince NASA to back it.

1989 was the last time Neptune and its moons were visited during a short flyby from the Voyager 2 spacecraft, which captured the first and only close up photos of this planet.

Moreover, Voyager 2 captured data showing potential plumes of water being blasted from the interior of Triton, which has caused many planetary scientists to take a closer look at Triton. Recently it’s been seen as a top priority for exploration under NASA’s Roadmap for Ocean Worlds.

Dr. Amanda Hendrix from the Planetary Science Institute in Tucson, Ariz., who is also one of the leaders of the Roadmap study, explained that Triton is a three-for-one target since you can visit the Neptune system, see the exciting ocean world, and also visit a Kuiper belt object.

She said that by examining places like this, they could gain fresh insights into how ocean worlds form, how they differ and how they manage to keep liquid water. For example, water in Triton’s ocean could be much colder than the typical freezing point, but ammonia could keep it in its liquid form. Clues like this will help us discover life outside of Earth.

Neptune is thirty times further from the sun than our planet, and although experts believed that the habitable zone ended at Mars, it is now thought that even a planet this far might be habitable. This is a result of an ocean discovered beneath Europa, one of Jupiter’s large moons, as well as beneath Saturn’s moon Enceladus.


Image Credit: NASA