Titan sea

Sometime in the next 20 years, NASA hopes to launch an ambitious robotic explorer to Saturn’s moon Titan. It won’t be the wheel-based rovers we’re used to seeing on Mars, though. Instead, an autonomous submarine will probe the depths of Titan’s methane (and ethane) oceans.

Not only will the submarine need to collect all kinds of data, but it’ll also need to maneuver around seabeds and hover at and below the surface. A tricky proposition given what we know about Titan’s oceans. The concentrations of ethane and methane aren’t constant. They can vary big time, and these variations change how dense the ocean is which could affect how the submarine maneuvers.

But it’s not all bad news. The test chamber used to simulate seas on Titan showed the freezing point at a lower than expected -324 degrees Fahrenheit instead of -296 degrees Fahrenheit. All thanks to a little bit of nitrogen.

“That’s a big deal,” said Ian Richardson, who helped create the test chamber. “That means you don’t have to worry about icebergs.”

The big challenge Richardson and other researchers were getting their first look at was the direct interaction between a simulated Titan sea and a submarine powered by a heat-producing machine. A two-inch cartridge heater shaped like a cylinder was placed inside the chilly methane/ethane mixture. Researchers watched as nitrogen bubbles formed.

Understanding these bubbles can have a big impact on the future mission. Too many bubbles and it’ll be a challenge to steer the submarine, gather data, and manage ballast systems. Icebergs aren’t one of the biggest potential problems. Bubbles are.

A Titan submarine concept

A submarine mission to Titan isn’t a lock. Tests like those performed by researchers like Ian Richardson help identify the challenges an underwater mission to Titan present. But there’s only enough funding to go around.

One concept was pitched in 2015. A submarine would explore Titan’s northern sea Kraken Mare. For 90 days, the submarine will travel 1,250 miles as it explores the surface and beneath of a methane sea comparable in size to the Great Lakes.

Data collected will focus on the chemical composition of Titan’s liquid seas, surface and subsurface currents, tides, waves, and more. This concept proposes a launch in the 2040s. That gives plenty of time for the hardware to be developed if NASA chooses to take this mission from concept to reality.

Here’s a short video explaining some of the science packages included in the concept.

Getting a submarine to Titan won’t be easy, or cheap. But nothing ever is in deep space. NASA’s been on a roll lately with the incredible New Horizons mission. Pluto wowed everyone. Can you imagine pictures from beneath an ocean on another planet? Make it happen NASA!