Titan is the largest moon of Saturn and is the solar system's only moon with an atmosphere that has pressure close to Earth's.
It was discovered by Christiaan Huygens in 1655, and not much more was known about it until the 1980s with most of the data coming within the last 15 years.
Cassini visited Titan and in 2004 it released the Huygens probe. Huygens parachuted into Titan's atmosphere and landed on Titan's surface. This feat was the first landing on any object in the outer solar system.
Huygens sent back lots of data about the composition of Saturn's surface along with several pictures taken upon entry. Some atmospheric data was lost as a result of a programming error which did not command Cassini to listen to Huygen's transmissions on a certain channel.
The challenges of Titan
To begin, Titan is a very, very, cold place. The surface temperature of Titan is around 94k (-180°C / -290°F) from being in the outer solar system and having a ethane/methane atmosphere. An unprotected human would flash freeze at those temperatures.
The gravity is also much lower than the gravity of Earth. 100lbs on Earth would weigh 14lbs on Titan.
These two negative traits counteract each other however.
Since Titan has a cryogenic surface, many materials enter a state of superconductivity. Superconductivity allows electricity to flow without resistance.
Superconductivity is essential to efficient hyperloop construction, which can be used for artificial gravity. On Earth, superconductive magnetic levitation systems are difficult considering not many materials enter superconductivity at normal ambient tempertures. The temperatures on Titan are optimal for mag-lev hyperloops.
A mag-lev hyperloop can be used for two very practical purposes. Launch-Propulsion & Artificial-Gravity.
By having large toroidal loops or corkscrews, a human could enter into a sleeping pod and be spun around at speeds in the thousands of miles per hour. This centrifigal force can generate enough gravity to sleep comfortably, while countering the effects of long term space travel like gravity sickness.
Spacecraft can be sped up and ejected from a hyperloop into space for propulsion. Considering the spacecraft would weigh 14% of its weight on Earth, it's a very feasible way of reaching escape velocity on Titan. For larger payloads the spacecraft can still be assisted by propellent and save significant amounts of fuel.
Lunar gravity is similar to Titan's gravity, and when placed in eternally dark craters the hyperloops would also work on the Moon. It would make sense for the technology to be used between the two moons for artificial gravity on bases.
Since Titan has a dense, hazy, atmosphere it makes taking some measurements of Titan difficult. It is understood that the atmosphere makes the surface of Titan cold and windy, heat would quickly be conducted away from anything on the surface. A subsurface base could be insulated by ice and nanomaterials. To achieve electricity for heat - Titan is very hospitable.
The wind of Titan makes wind turbines very feasible and the cold allows for long distance transmission of power to less turbulent regions of the moon.
Titans dense atmosphere and surface are also abundant with methane/ethane gas and liquid. These hydrocarbons are much less rare on Titan compared to their rarity on Earth. Titan's surface is abundant with fuel.
However in order to combust hydrocarbons for power, oxygen is required.
Titan is believed to have oxygen, however this oxygen is trapped inside of an ocean of water speculated to be 60 miles under the surface. Since use of electrolysis is necessary to seperate the oxygen from the hydrogen (which can also be used for fuel) power would still be needed from other processes.
Another source of oxygen could be Saturn's other moons, Dione has displayed trace amounts of oxygen - however electrolysis still seems to be more reliable.
The lunar surface is primarily oxides which may be an alternative source of oxygen. The Moon is abundant with oxygen and can also store Titan's gases in eternally dark craters. Helium-3 is also available on the Moon to enable nuclear power to seperate oxygen from other elements. The compatibility of Titan's gases with lunar gases could enable access to the outer solar system.
Since water is necessary for many reasons on Titan it would still be essential to make use of the subsurface ocean. Accessing the ocean will require penetration into 60 miles or more of solid ice. Current Earth mining technology has not acheived this depth, but this is mostly due to heat. On Titan the depth could possibly be acheived using autonomous mining robots drilling deliquetely through the ice with heat. By gaining access to this oxygen a mission would be supplied with water for drinking/food consumption and hydrogen fuels that can easily be stored in such a cold enviroment.
Another benefit of accessing the subsurface ocean is to observe Titan's core. Earth's core is hard to study due to extreme heat and density. Titan has a smaller, cooler, silicate core with a mostly liquid 'mantle'. It's a very appealing additional reason to access the ocean.
Titan is not the only place believed to have a subsurface ocean. Europa a moon of Jupiter, has geysers indicating a subsurface ocean covered in ice. However Europa is surrounded by extreme levels of Jupiter's radiation that could quickly kill humans and most known forms of life. Some space agencies have placed priorities on programs to study Europa's ocean for life, however the conditions are harsher on Europa. Considering that Jupiter's radiation has likely been present prior to the formation of Europa's ice sheets - the water may already be sterile. Titan does not experience the same level of radiation that Jovian moons experience, and has much more carbon - a crucial building block for life after water.
Other moons of Saturn are believed to host water, like Enceladus. The resources of Saturns 50+ moons offer many In Situ resources. Saturn's gravity well could also provide interesting metallurgy research.
Since Titan has low gravity and dense atmosphere, it is much more ideal than Earth for space launches. Coupled with hydrogen fuel and superconductive launch assistance, access to surrounding moons could also be feasible in terms of gathering resources. Titan could also harbor a spaceport for asteroid belt mining operations, and deep space exploration.
With current methods of space travel, it would be optimistic for a spacecraft to reach Saturn in around 5 years. It would be benefecial to cut trip time for humans by laying out fuel tanks along the journey to accelerate the crew to top speeds, while keeping the overall craft light. Space Elevators as mentioned in the moonbase log are also equally compatible with Titan, although will need to be designed for an atmosphere similar to Earth's.
It would be effective to eject fuel tanks out of Titan's orbit and guide them along a route to remain stationary in Earth orbit. Cargo travelling toward the Sun will consume less fuel than cargo travelling away from it. Having a supply chain of fuel cargo between the Moon and Titan will enable faster travel to the Saturnian system. Titan's atmosphere is similar to Earth's and it could even be feasible for modified aircraft could fly in it, as shown by this xkcd comic about an inplanetary Cesna.
Reaching Saturn quickly is a major challenge. Such methods would require intelligently designed docking systems, be refuelable, and built to store cold liquid fuels like ethane, methane, hydrogen, oxygen, and helium-3. The fuel tanks should be designed to detach when enough fuel remains for the tank to reach Saturnian or Lunar orbit. These tanks should be reused for storage, and transport.
Throughout the journey hyperloops could be used with sleeping pods to induce gravity in scheduled regimens, coupled with a physical fitness program. Titan's lower gravity will help with rehabilitation from zero gravity and be less severe than what ISS astronauts experience from Earth re-entry.
Aeroponic systems using Carbon Dioxide enrichment and Photosynthetically Active LEDs can produce food quickly and save 90% more water. Aeroponic systems can be used for CO2 filtering up to 2000ppm, or 5 times the atmospheric levels of Earth. The plants absorb hydrogen and carbon, releasing oxygen for breathing.
Titan has ethane/methane fuel, water, plus local access to 60+ moons with a big gravity well. Saturn's orbit is powerful and can propel fuel transports between the bodies. The Moon is a better rendezvous point than Earth and has a similar gravity profile as Titan, even similar temperature conditions in certain places. Our Moon and Titan are not so different. The equipment used on these moons such as spacecraft, life-support systems, fuel containment, and artificial gravity systems can be equally compatible. Shipping methane to the Moon and oxygen back is a sustainable way of exploring the outer solar system and beyond.