You may have seen the recent news coverage of a Nature article describing the discovery of a large lake of liquid hydrocarbon (presumably methane) in the equatorial regions of Titan, one of Saturn’s moons. Science fiction writers like Robert Heinlein and Isaac Asimov helped create visions of human colonies on Titan, and its complex atmosphere suggested to scientists that it bore some key resemblances to Earth. While exciting from a scientific standpoint because previous models of methane behavior on Titan suggested that lakes could not form outside its polar regions, the discovery also has energy-related implications.
The liquified natural gas in today’s energy market is primarily liquid methane, which has been artificially cooled and maintained in that state for transport before being converted back to a usable form when it reaches its destination. The associated costs for the vessels and terminals involved in LNG conversion and transport run into the hundreds of millions of dollars, but the technology is established and widespread.
Could NASA someday achieve the dream of a Titan colony using LNG? On Titan, transport costs could be minimalized by locating near the lakes, requiring only regasification and storage technology. NASA has tested methane-powered rocket engines, but most of its current habitation technology, such as that used on the ISS, is built around solar sources. However, it’s not always convenient to lug around a 73-meter solar array. At a distance from the sun of 9.0-10.1 AU (an average distance of around 891 million miles) depending on its position in its elliptical orbit, Saturn and its satellites aren’t exactly local. And Titan’s atmosphere might affect the viability of solar-based technology on the surface. The presence of an abundant surface energy source, however, could have a game-changing effect on the chances of a colony’s survival – if we can get there.