After Rovers, NASA Sets Its Eyes On Unmanned Submarines

One could probably say that NASA has gotten land and aerial space travel down to a T, with numerous rockets, satellites, and rovers under its belt. One thing that is quite novel for it is underwater exploration. But being NASA, it is, of course, more interested in water that isn't on Earth. Now the world's premiere space agency is making plans to design and build a drone submarine, one that would travel to space and explore Titan, one of Saturn's many moons.

Titan is of particular interest to scientists as far as moons go. For a moon, it is larger than Mercury. It is also the only one that has a proper atmosphere. Of course, it's composition is quite different from earth. Flyby's of probes and a Hyugen probe landing revealed that Titan has three large polar seas, the largest of which is the Kraken Mare, an arctic sea 400,000 sq. km. in size and 160 to 300 m deep. It has tides, a shoreline, and evaporite deposits. In other words, a treasure of knowledge waiting to be discovered.

The Titanian submarine will be patterned after similar drone submersibles here on our planet, but Titan's distance and composition present a formidable challenge for NASA. It is planned to weigh about one tonne/2,200 lbs. And its elongated shape means it can't simply be dropped off like a rover. It will have to be delivered to the planet surface by an aircraft that can withstand a hypersonic entry into the moon.

The composition of the water itself is a problem, being made mostly of methane and ethane, similar to liquefied gas. It is so cold that the water is almost like a natural cryogenic environment. This will cause the water surrounding the water to immediately boil just from the waste heat of the submarine's 1 kW radiothermal Stirling generator. At the same time, the submarine's system must also be kept warm to prevent freezing. Definitely a difficult balancing act.

NASA is planning to subject the submarine to a 90-day mission that would span 2,000 km, with the submarine traveling at a speed of 3.6 km/h. Every day, it will surface for 16 hours to phone home, to do away with the need for a more expensive nuclear orbiter. Given the distance between Titan and Earth, however, there will be very little control coming from us and the submarine will operate with a good amount of autonomy.

VIA: Gizmag