Once propulsion challenges are overcome, allowing humans to travel great distances quickly without incurring significant radiation damage, Saturn’s moon Titan is the optimal location in the solar system for an off-Earth human settlement. It has Earth-like qualities and a thick atmosphere that provides shielding from damaging radiation unlike any other solid surface location in the solar system. Given the distance from Earth (~1.3 billion km), such a settlement must be self-sustainable, and in particular, humans will need to produce oxygen to breathe and provide heating for habitats. The abundance of hydrocarbons and availability of wind and hydro-based power give this self-sustainability a high likelihood. Here we discuss such energy options, from In Situ Resource Utilization (ISRU). This paper represents an exercise to provide a first look at energy options without delving into tedious detail on each one (at a time when questions about specific Titan conditions still exist), to provide readers with estimates of energy options for future study. Clearly, many details will need to be worked out in the coming decades, such as equipment mass required for delivery to Titan for any one of these systems.
Titan’s natural resources present several options for useful energy sources for future visitors (or colonists/settlers) to the moon. Combustion of hydrocarbons alone is not eٹcient (due to the need to produce O2 via electrolysis or other means), but hydrogenation of acetylene produces 376 kJ/mol, and hydrogenation of the abundant atmospheric nitrogen produces 92 kJ/mol. Other energy-producing chemical pathways are likely available.
An alternative to chemical energy is hydropower, utilizing Titan’s large methane-ethane-filled seas and lakes to produce power as with hydropower here on Earth. Due to Titan’s lower gravity, the power production is less than 20% of that on Earth, but the vast size of Kraken Mare, Titan’s largest sea, would allow for power production for tens of thousands of Titan years. Detailed study of such an option requires improved knowledge of the topographic variations in and around the high latitude lakes and seas.
Wind power is a viable option. Wind speeds are low on Titan compared to Earth, but the atmospheric density is higher. Energy production would be relatively low at the surface of Titan, however the higher wind speeds at tens of km altitude could be accessed, e.g. by balloon-borne wind stations.
Researchers looked at the possibilities for in situ energy resources on Titan for use by future humans, including chemical, nuclear, wind, solar, geothermal and hydropower. All of these options, with the possible exception of geothermal, represent effective sources of power. Combustion of methane (after electrolysis of the native water), in combination with another source of power such as nuclear, is a viable option; another chemical source of energy is the hydrogenation of acetylene. The large seas Kraken and Ligeia potentially represent effective sources of hydropower. Wind power, particularly at altitudes ~40 km, is expected to be productive. Despite the distance from the sun and the absorbing atmosphere, solar power is (as on Earth) an extremely efficient source of power on Titan.