May 13, 2021: Could We Harness The Resources Of Titan In Any Complex Mission To That World ?
Titan, the largest moon of the Gas Giant Saturn, is a captivating world that looks like the Earth to a certain extent. That opaque or hazy world is clearly one of the key targets of NASA in terms of exploration. Titan has all the ingredients to draw the attention of planetologists, exobiologists or meteorologists. That natural satellite of the Ringed Planet contains a relatively significant atmosphere, dune fields extending over long distances or lakes, seas and rivers in its high latitudes. In a way, Titan represents a natural laboratory to study the chemistry of organics and hydrocarbons or to study the potential prebiotic chemistry. The Cassini-Huygens mission in the Saturn System has allowed us to gather a huge amount of data regarding the complex environment of Saturn's largest moon. We have noticed that Titan is a dynamic world where erosion processes generated by rainfall events, rivers, lakes, seas or winds can be identified. Some researchers advance that the atmosphere of Titan looks like the atmosphere of the Early Earth. The atmosphere of Saturn's largest moon is dominated by molecular nitrogen like the atmosphere of the Earth but the atmosphere of Titan also contains a relatively significant fraction of methane.
Oxygen is absent or almost absent in the atmosphere of Titan. That's a major difference between the atmosphere of Titan and the atmosphere of the Earth since the atmosphere of the Earth contains around 21 percent of oxygen. The molecules of oxygen present in our atmosphere are mainly related to our biosphere. In the harsh environment of the Opaque Moon, a molecule like carbon dioxide or CO2 will tend to appear in its solid form. That's also the case for water that will tend to appear in the form of ice on the surface or in the soil. The Huygens probe had landed onto the surface of Titan at a low latitude on January 14, 2005 and had recorded an ambient temperature of about minus 179 degrees Celsius, minus 290 degrees Fahrenheit or 94 Kelvin at the level of the surface. Therefore, the environment is extremely harsh and allows molecules like methane (CH4) or ethane (C2H6) to appear in their liquid form on the surface. Methane is in fact the second most abundant gas in Titan's atmosphere. A parallel can be drawn between the meteorological cycle of the Earth mobilizing water and the meteorological cycle of Titan mobilizing methane.
The infrared or near-infrared views as well as the radar images obtained from the Cassini orbiter during its orbital dance in the Saturn System have clearly shown that methane can form clouds, generate rainfall events or produce rivers, lakes or seas. Several types of liquids involving hydrocarbons can potentially be encountered on the surface of Titan. The composition of any sea or lake can depend on the season or the area. Planetologists believe that the lakes, seas or rivers tend to be composed of a mixture of methane, ethane and dissolved nitrogen. The aerial views acquired from the Huygens lander had revealed bright hills containing a network of dark drainage channels demonstrating that it must rain from time to time in the area. The radar views taken with the Radar Mapper of the Cassini spacecraft have shown that the dark areas of the low or mid-latitudes tend to be dominated by linear and parallel dunes extending over long distances. Thus, the dune fields may potentially represent ancient seas or oceans. The Huygens probe had landed into a dark or brown plain marking a sharp contrast with the bright hills. The color image captured from the surface revealed strongly eroded stones or pebbles. Did the probe land into an ancient river or brook ?
The Cassini-Huygens mission in the Saturn System has clearly shown that Titan is a fascinating world that unveils major mysteries and that can unveil major clues regarding the origin of life on Earth. We must go back to Titan and there are ambitious projects for the exploration of that enigmatic world. Some researchers and engineers are currently developing a mission involving a rotorcraft and known as Dragonfly to explore the environment of Titan. The rotorcraft may fly in the environment of Saturn's largest moon to explore it in the 2030's for a relatively long duration. The rotorcraft may study the enigmatic dunes in particular. However, it won't explore the land of lakes, seas and rivers found in the polar region of the northern hemisphere. A new project to Titan may appear even more ambitious. That project is a project that consists in collecting surface samples in order to return them to our own planet for laboratory analysis. Planetologists or engineers try to see whether we can harness the resources of the Opaque Moon to generate fuel or energy. The new concept which can appear particularly complex at first sight is proposed by a team involving Steven Oleson of Glenn's Compass Lab.
The project was selected for a $125,000 NASA's Innovative Advanced Concepts (NIAC) program grant to start analyzing the feasibility of the potential mission. That's clearly a complex project that will require a lot of work to prepare the spacecraft, the probe or the journey. Thomas Zurbuchen who is the associate administrator for the Science Mission Directorate of NASA pointed out: "NIAC is one way the agency fosters 'wild' ideas that require a decade or more of development but could eventually lead to revolutionary innovations that contribute to new and exciting missions." He added: "The missions of today were 'wild' ideas years ago." The team of Steven Oleson had already developed an ambitious concept to explore Titan. Their former project mobilizes a submarine to explore the seas or lakes of the Orange Moon. Researchers could also gather clues regarding the potential internal ocean dominated by liquid water beneath the external crust. Geoffrey Landis who is the science lead investigator for Compass advanced: "Titan is an amazing world." He added: "It is covered in organic compounds protected with a thick nitrogen atmosphere and has liquid natural gas seas the size and depth of Earth's Great Lakes on its surface. And beneath its crust, Titan is an ocean world, with a second ocean of liquid water hidden deep below the surface."
The soil of Titan may be rich in water ice and may contain relatively significant concentrations of hydrocarbons or organics. The dark or brown areas may be dominated by a type of mud or sludge called tholin. Researchers have been able to reproduce that substance in the laboratory. Tholins can be encountered in the Outer Solar System on worlds like Europa, Titan or Pluto. Can tholins engender more complex molecules like amino acids or proteins ? That's a major question that we may be in a position to answer in a relatively near future. Planetologists and engineers can mobilize lightweight instruments on any probe to analyze the key compounds of a sample. However, that configuration has some limits and the configuration of a sample return mission for an in-depth analysis in the laboratory naturally appears to be the best option. The gravity of Titan is much lower than the gravity of the Earth and is even lower than the gravity of our own moon so that the launch of any rocket from the surface of Titan can appear easier than on Earth. However, the air at the level of the surface on Titan is much denser than the air at sea level on Earth. The air represents a resistance to the movement.
Steven Oleson pointed out: "We expect landing on Titan to be relatively easy." He added: "Titan has a thick atmosphere of nitrogen - 1.5 times the atmospheric pressure of Earth - which can slow the lander's velocity with an aeroshell and a parachute for a soft landing, just like astronauts returning to Earth." A parachute is very efficient to slow down the atmospheric descent of any probe thanks to the relatively high density of the air close to the surface. The air on Titan at sea level is much denser than the air on Earth at sea level or than the air on Mars near the soil so that any rocket to slow down the probe during its atmospheric descent is not needed. The team of Steven Oleson will perform some studies to analyze whether any probe or rocket could use compounds of Titan's air, Titan's surface, Titan's seas, lakes or rivers to generate energy or to collect or generate fuel in the environment of that exotic world. A lot of energy is required to leave Titan. That's why the use of resources on the Opaque Moon to generate a propellant to return to the Blue Planet is likely to significantly simplify the mission of the probe, drone or submarine.
Geoffrey Landis argued: "Our aim is to design a cost-effective modern mission concept that could find and use resources at the destination." Is that type of mission really feasible ? Steven Oleson advanced: "Producing rocket fuel on Titan wouldn't require chemical processing - you just need a pipe and a pump." Any probe, boat, submarine or drone can mobilize the liquid methane or the liquid ethane found in the lake, sea or river. Let's note however that the lakes, seas and rivers are mostly found in the high latitudes of each hemisphere. Liquid hydrocarbons are not everywhere on Titan ! Can we generate oxygen from the environment of Titan ? Some samples of the soil which are dominated by water ice could be melted by resorting to the heat produced by a nuclear source. Once the water molecules appear in their liquid state, a process of electrolysis can take shape to generate oxygen. The nature of the soil on Titan is a major topic of research. The Huygens probe had revealed a relatively high concentration of methane during the landing process demonstrating that any probe or drone can potentially collect relatively high amounts of methane where it lands or evolves.
The image above corresponds to a portion of a radar swath of Saturn's largest moon Titan obtained during the T19 Flyby performed on October 9, 2006 by the Cassini spacecraft. One can notice three major lakes in particular. The lakes, seas and rivers on the Opaque Moon tend to be dominated by liquid methane. Each side of the radar portion represents around 100 kilometers (around 62 miles). Credit for the original radar view: NASA/JPL/Cassini Radar Team/Jason Perry.
- To get further information on that news, go to: https://www.nasa.gov/feature/glenn/2021/glenn-researchers-study-new-futuristic-concept-to-explore-titan .