Exploring Titan with Dragonfly

Saturn's moon is alien in many ways, but there's a chance life could form there, and Dragonfly's mission is to find out

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Mars gets a lot of our attention since it’s the closest planet to Earth, and people are already training to live permanently on the red planet’s surface. Don’t get me wrong, learning about Mars is fun, but… in my opinion, the barren, red, rocky planet is a bit boring compared to the rest of our solar system. Titan, for instance, is anything but bland.

While larger than the planet Mercury, Titan is technically a moon that orbits Saturn — and it may be capable of hosting life. Its distance from Earth makes it challenging to study, but scientists have learned quite a bit. Thankfully, NASA has plans to learn significantly more with its Dragonfly rotorcraft lander mission, which just passed preliminary design stages and is allowed to proceed to its final construction.

Titan

As I mentioned, Titan is one of Saturn’s moons, but it’s much larger than ours. In fact, Titan is the second-largest moon in our solar system. Second only to Jupiter’s moon, Ganymede, which is merely 2 percent larger than Titan.

Saturn is the sixth planet from the Sun, with Mars and Jupiter between it and Earth. It takes Saturn about 29 Earth years to orbit our Sun once — so one Saturnian year = 29 Earth years — and it takes Titan 15 days and 22 hours to complete an orbit around Saturn. Considering the distance from the Sun, sunlight takes about 80 minutes to reach Saturn and its Titan moon, and the light shines about 100 times fainter than on Earth.

Layers of Titan

There’s plenty to learn about Titan’s internal structure, but various space missions, especially NASA’s Cassini-Huygens mission, suggest the Titan moon has five main layers.

Titan’s deepest level is a core measuring roughly 2,500 miles (4,000 kilometers) in diameter and is likely made of water-bearing silicate rock. Surrounding the rocky core is a shell of a particular type of water ice called ice-VI, which is only made at extremely high pressures and is as hard as rock.

Coating the ice-VI is a layer of salty liquid water, which is covered by an outer crust surface made of water ice blanketed with organic molecules that settle to the moon’s surface as sand or liquid.

Lastly, hugging Titan’s surface is a dense atmosphere that, like Earth’s, is mainly made of nitrogen (about 95 percent), but Titan’s atmosphere also has about 5 percent methane and small amounts of other carbon-rich compounds.

Atmosphere

High up in Titan’s atmosphere, the Sun’s ultraviolet light combined with high-energy molecules in Saturn’s magnetic field split nitrogen and methane molecules apart. Then, pieces of these molecules recombine to create other organic chemicals that contain hydrogen, carbon, and other elements vital to life as we know it.

Titan is the only other place in the solar system that we know of with a cycle similar to Earth’s water cycle. On Titan, liquid rains down from clouds and flows across the surface, creating seas, lakes, and rivers, then evaporating back into the sky. Except instead of water like on Earth, it’s mostly liquid methane and ethane that rain down on Titan.

“Hazy Day on Titan” Image Source: NASA

Surface

Being so far away from the Sun means Titan is super-duper cold. Titan’s surface measures –290 degrees Fahrenheit (–179 degrees Celsius, or 94 kelvin), far too frigid for life as we know it to exist. It’s a place where ice-IV plays the role of rock, and liquid methane and ethane fill great lakes and carve out river channels across Titan’s surface.

And get this: according to NASA, “Titan may have volcanic activity as well, but with liquid water ‘lava’ instead of molten rock.”

Below Deck

The Cassini-Huygens spacecraft took gravity measurements during fly-bys, which revealed an ocean beneath Titan’s icy shell of a surface. Even more amazing, it appears the conditions within this ocean could be suitable for life to form.

Life?

While it’s literally the definition of ‘otherworldly,’ Titan seems to contain all the necessary ingredients for some sort of life to form — making it a prime location to search for life within our solar system.