February 9, 2018 : Scientists From Washington State University Simulate An Alien Sea Of Hydrocarbons To Test An Exploration Submarine Of NASA
Researchers from Washington State University have performed a laboratory simulation of the alien sea or lake that one may encounter on Saturn's largest moon Titan. The experiments regarding the dynamics or the composition of the seas or lakes are needed to build a suitable submarine for the exploration of the north polar lakes or seas on the Opaque Moon. NASA is planning a new mission to Titan within the next twenty years and there are several projects involving probes, drones, boats or even submarines. The engineers or scientists re-created the presumed seas or lakes of hydrocarbons in the laboratory and simulated an environment where the environmental temperature is around minus 300 degrees Fahrenheit. Let's recall that the surface temperature recorded from the Huygens probe on January 14, 2005 after landing was minus 179 degrees Celsius that is to say minus 290 degrees Fahrenheit or 94 Kelvin. The lakes or seas of Titan are likely composed of a mixture of methane and ethane.
The laboratory experiment was fundamentally designed to simulate the behavior of any submarine beneath the surface of a sea or a lake on the giant moon of the Gas Giant Saturn. The simulation was developed by Ian Richardson who is a former graduate student in the School of Mechanical and Materials Engineering. The experiment in the cryogenic laboratory of Washington State University is described in a paper released in the journal Fluid Phase Equilibria. The behavior of liquid hydrocarbons in the pools of Titan's surface may be quite surprising and may be more difficult to manage than in the oceans or seas of liquid water on Earth. Researchers are ambitious for the next step in the exploration of the Hazy Moon. Any probe sent to Titan will have to study the atmospheric conditions where complex organics or hydrocarbons can take shape and will have to study the environment of the lakes or seas as well as the internal phenomena related to the pools of liquids. Will the heat generated by the submarine and its movement engender the emergence or the development of nitrogen bubbles inside the lake or sea explored ?
Engineers are collaborating with scientists to design a probe or a submarine which will be well suited to study the lakes or seas found at a high latitude in the northern hemisphere of the Orange Moon. The submarine must be autonomous and resistant in order to obtain quality data of its environment and to transmit the data to the orbiter or directly to our receivers on Earth. Researchers know that there is a meteorological cycle involving methane on Titan. A parallel can be drawn between the methane cycle on Saturn's largest moon which is the second largest moon in the Solar System and the water cycle on Earth. On the Opaque Moon, there are evaporation processes, condensation processes, cloud formations and rainfall like on Earth. However, the properties of liquid methane may be quite different from the properties of liquid water. That's why researchers perform some simulations with various hypotheses regarding the nature of the liquids on the Hazy Moon.
The pools of Titan may not be homogeneous as opposed to the pools of liquid water on Earth. There may be some variations in the composition of the pools dominated by hydrocarbons on Titan. For instance, the properties of the liquids may change at certain depths or the composition of the liquids may be different in some areas. The composition of Ontario Lacus, the first lake or sea identified on Titan, in the high latitudes of the southern hemisphere, may be very different from the composition of Kraken Mare, the largest pool of liquids, located in the high latitudes of the northern hemisphere. The composition of the lakes or seas may also vary due to seasonal factors. Currently, the northern hemisphere is experiencing the Summer season. Will the level and the size of the lakes, seas and rivers diminish in the northern hemisphere in the coming years as the Summer season advances ? Will the level and the size of Ontario Lacus increase in the coming years as the Winter season advances ? Are there implications for the density or the behavior of the liquids ?
Ian Richardson, who holds a bachelor's degree in mechanical engineering from Washington State University and who was WSU's first-ever recipient of a NASA Space Technology Research Fellowship which incorporated an internship at NASA's Glenn Research Center in Cleveland, Ohio, has had the opportunity to mobilize his technical skills, to use the cryogenic laboratory of WSU to simulate the alien environment of the seas, lakes or rivers on Titan and to analyze the interactions between the liquids and the experimental submarine which produces its own energy to operate. The cryogenic laboratory is well suited to analyze materials at very cold temperatures and to simulate the harsh environment of Saturn's largest moon. Ian Richardson cultivates a passion for space and space exploration. The fate does things well because a NASA researcher approached him to discuss about the project of designing a well-suited submarine for the exotic seas or lakes of Titan. At the time of the meeting, Ian Richardson was working as an intern on a different problem. He pointed out : « My research just took a right turn, and I went with it. » He added : « It's a crazy experiment, and I never thought I would have had this opportunity. It's been a very fun and challenging experimental design problem. »
In order to simulate the seas or lakes dominated by liquid methane and liquid ethane on Saturn's largest moon, the team of scientists from WSU designed a test chamber that hosted the liquid mixture at particularly cold temperatures. Ian Richardson and his collaborators introduced a two-inch, cylinder-shaped cartridge heater that would generate, roughly, the same amount of heat that a submarine would produce. One of the major problems anticipated or predicted by scientists is related to the presence of nitrogen which is likely present in the liquid of the seas or lakes found in the high latitudes of Titan's northern hemisphere. There may be dissolved nitrogen within the lakes or seas and the production of heat may engender the emergence or the development of bubbles of nitrogen around any submarine exploring the seas or lakes of the giant moon. As a result, researchers want to study the interactions between the experimental submarine and the liquids dominated by hydrocarbons and containing nitrogen. The submarine will produce energy and the diffusion of the energy around it will likely engender nitrogen bubbles. A high concentration of nitrogen bubbles is likely to complicate the task of the probe or submarine, to make it difficult to maneuver the craft, to see the environment, to obtain data and to manage ballast systems.
One of the major goals is to obtain clear images or to produce a video of the extremely harsh environment. The experimental work was performed at 60 pounds per square inch of pressure and almost minus 300 degrees Fahrenheit. The team of Ian Richardson designed a solution mobilizing an optical device called a borescope and a video camera that could resist the low temperatures and high pressures to see and analyze what was taking shape inside the test chamber. Ian Richardson pointed out : « Those aren't the friendliest conditions.» He argued : « You have to come up with creative solutions.» The group achieved its goal and obtained a satisfactory video sequence unveiling ethane-methane rain as well as snow. The team of Ian Richardson also analyzed the freezing temperatures for methane and ethane lakes. The researchers found that, due to the presence of a small amount of nitrogen in the liquid, the pools of liquid freeze at lower temperatures than would be expected. The freezing temperature of the liquid is 75 Kelvin, minus 324 degrees Fahrenheit or minus 198 degrees Celsius instead of 90.5 Kelvin, minus 182.7 degrees Celsius or minus 296.8 degrees Fahrenheit. Ian Richardson advanced : « That's a big deal.» He added : « That means you don't have to worry about icebergs.»
The scientists and engineers working on this simulation are about to pursue the analyses and the work on the design of an experimental submarine for the seas, lakes or rivers of the Orange Moon. Planetologists are particularly interested in the chemistry of Titan's atmosphere and in the chemistry of the pools of liquids located in the high latitudes of the Orange Moon. Radar data, infrared and near-infrared data acquired from the Cassini orbiter have allowed us to observe remarkable surface features on the Opaque Moon. One can notice in particular the Cat Scratches or the Seif Dunes in the low-albedo areas of the low latitudes. But the seas, lakes and rivers found in the high latitudes appear to be the most captivating features on Titan because we want to know whether they can engender complex molecules, hydrocarbons or organics. Can they lead to an exotic lifeform ? The environment of Titan is a good place for drones or probes which can fly because the air is particularly dense near the soil. The drone or flying probe can easily obtain panoramic views like the views taken from the Huygens probe during the atmospheric descent on January 14, 2005. Developing or designing a submarine is clearly a more complicated task than designing a surface probe because we don't know the exact nature and the exact properties of the liquids on the surface of Titan.
This mosaic based on near-infrared data taken from the Cassini spacecraft during the T104 Flyby of August 21, 2014 clearly reveals the lakes or seas located in the high latitudes of the northern hemisphere of Saturn's largest moon Titan. Data obtained from the Visual and Infrared Mapping Spectrometer were used to produce this global view. There is a meteorological cycle implying evaporation processes, condensation processes, cloud formation and precipitation on the Hazy Moon. The properties of the liquids on Titan's surface represent a big question mark. Image Credit: NASA/JPL-Caltech/University of Arizona/University of Idaho.
- To get further information on that news, go to: https://news.wsu.edu/2018/02/07/wsu-builds-nasa-alien-ocean.