Harvesting Geothermal Energy on Mars for Future Settlement

0
163

Authors: Sanmathi Priya Abiram Lakshmi Devi, Ananya Nagireddy, Smruthi Srinivasan
Editorial Support: Risha Roy, Sanya Rajput, Shree Singal, Manavi Panjnani
Professional Reviewer: Dr. Dale E. Gary

I. Introduction

Our initial step to forming our research topic was to conduct an analysis on the properties and surface features of a Martian landform called Gale crater (see Figure 1) which was provided on the Mars Student Imaging Project (MSIP) website. We hypothesize that specific regions of Mars oriented in lower elevation near volcanic regions including features such as fissures, fault lines and hot springs are highly suitable for geothermal energy. Deeper research in this field can provide greater understanding for a sustainable source of energy for future Martian civilizations.

Our features of interest that we initially observed include: sand dunes, or mounds of sand formed by wind that are remains of ancient dunes[13]; simple channels, or structures that cover large stretches of land that are remnants of flowing water; yardangs, or ridges created through wind erosion that are found on sloping areas, craters, formed by volcanic activity or meteorite collisions; lava flows, or discontinuous levees that form from the rising magma from the planet’s interior[12]; and fissures, or narrow openings of breakage by the cracking and splitting of rock and land. This led to deeper research into the Gale crater as we found that the particular site harbored a great variety of features compared to those in other THEMIS images. A greater variety means that the team could choose specific features that we believed would offer more insight into our chosen theme of geothermal heating. Of all the features we analyzed, the prominent lava flows that appear on the inner sides of the crater were the most striking because they indicate possible past tectonic activity on Mars. We used the software Java Mission-planning and Analysis for Remote Sensing (JMARS) to find out more information on other locations on Mars with lava flows and fissures, we reviewed four main locations (Vernal Crater, Cerberus Fossae, Elysium, and Valles Marineris), which exhibited these features. After selecting our four main sites, we conducted preliminary research on these sites and their features to learn that they could potentially be locations of high geothermal activity. Lava flows indicate previous active volcanic activity and shallow ground, while fissures indicate tectonic plate borders and nearby volcanoes. Overall we were able to draw the conclusion that lava flows and fissures would be a gateway into researching geothermal activity on Mars.  

Our overarching research objective was to determine specific land features on Mars that could eventually impact the potential use of geothermal energy for future settlement.

II. Geothermal Energy Overview

Geothermal energy is defined as heat energy that radiates from beneath the Earth’s crust from the deeper layer of magma, or molten metals. The heat energy results from the decay of uranium and potassium in the magma. Geothermal energy originates from below the ground and escapes out of the crust through various venting landforms such as hot springs, hot rock, magma, reservoirs of heated water. [4]
More specifically on Earth, the mantle underneath the Earth’s crust boils underground water collected in the in-crust reservoirs of the Lithosphere. If the magma causes water to become hot enough, the steam, which retains geothermal energy, can create cracks in the Earth’s crust, and escape through plate boundaries. It can then be harnessed through underground pump systems which then pass the energy through a heat exchanger to convert the Geothermal energy into a usable energy source for electrical power generation. Geothermal energy can also be extracted from hot dry rocks which are fractured with moisture to build geothermal reservoirs in them [2]. Nevertheless, the most common geothermal plant is the dry steam technique-based plant which works through a network of large pipes as shown in Figure 2. The pipes are inserted into the crust deep enough to collect a heated stream which flows to a turbine and allows it to generate electricity. There are multiple processes used to harvest geothermal energy. However, the main process is to either directly harvest steam which will drive a turbine to create electricity, or collect heated water from the ground, and then cool it to make it “flash” or quickly release vapor. The directly harvested steam would be readily available vapor that can turn the turbine on its own, while the heated water is used to provide heat for a heat transfer solution which is highly volatile, meaning it has a higher potential to turn to vapor that can turn the turbine: the heat transfer solution fulfills the role of geothermal steam (see Figure 3) [3].

Below is a list that we compiled of Earth landforms with the greatest potential to harbor geothermal energy[10]. We utilized this list to identify similarities between our observed Martian landforms and Earth’s landforms to apply known research to our selected landforms: 

  • Hot Spots – regions with greatest subsurface temperatures are active or young volcanoes 
  • Faults – regions with high seismic activity 
  • Hot Dry Rocks –  underground (3-5 mi below surface) heated rocks that lack the presence of water
  • Hot springs/reservoirs – surface-level outlets of both boiling water and steam 
  • Fissures – cracks that result in Earth’s surface due to groundwater depletion overtime
  • Ridges – peaks of land due to convergent tectonic plate activity 
  • Lava Flow  – magma that retains heat, rises to the surface 
  • Troughs – low points on the Earth’s crust, makes geothermal heat more accessible 

From the list, we deepened our research into two landforms which we found to be consistently prominent on the Martian surface as well—Lava Flows and Faults.  

Lava flows form when magma rises from beneath the planetary crust and pours out onto its surface. As the magma travels downhill from the eruption source it typically expands, resulting in the creation of lava tubes, which are channels of lava that form if the lava is extremely heated and fluid, and lava channels, which are channels shaped by water and can cool lava that flows through them. The impact of lava flow is that it can carve paths on the planet surface that look similar to riverbeds or canyons called meandering channels on the surface of Mars. Another impact of lava flows are the gases it releases; gases such as CO2 , SO2 , H2S, and HF released from the liquid portion of magma can eventually be released into the atmosphere. The second geological feature, Faults (see Figure 4), are related to earthquakes and tectonic plate movement caused by volcanic activity. Depending on which way tectonic plates are moving, they can create different fault lines, or breaks in the ground. Two plates can interact by coming toward each other, pulling away from each other, or grinding in opposite directions next to each other. These can create noticeable structures and changes in the local environment at the fault line, or where these plates meet. In particular, when the rocks in a fault area gain heat through the friction of the seismic activity, the spontaneous rise of heat causes the rocks to react and thus changes the composition of the rocks. The rocks can become extremely hot and possibly even melt due to the increase in temperature.[8] Faults contain an immense amount of energy due to the reaction that the rocks undergo through the earthquakes that take place. [9]

Wikimedia Commons, Creative Commons Attribution, Figure 5: As seen in the type of faults shown in this image, the rapid change in pressure and friction causes a buildup of energy.

Two other geological features specifically related to volcanoes that we selected to look at in depth were fissures and lava (see Figure 5) formed through volcanoes, as they often lead to the buildup of energy and are areas containing high amounts of heat. [15]  Fissures are defined as cracks due to volcanic activity and the movement of lava, which develop through dykes that widen when magma flows. Fissures are most common near volcanoes like Olympus Mons, the Cerberus region, releasing high amounts of heat due to volcanic activity[18]. Furthermore, lava flows are also features that contain high amounts of heat, essentially created through the magma that is part of the volcanic activity, composed of the molten rock that erupts, with the lava spreading across the surface and travelling downhill from the volcanic activity. The lava flows can also form and move away from the fissure and can include lava channels as well, the stream of the molten lava that flows and eventually hardens with the molten rock [7].The eruption of a volcano also leads to the formation of Calderas, essentially hollows near the top of the volcanoes that develop as the magma is released from below, leading to the ground above the source of the magma to deform and form the hollow[16].

Mars Student Imaging Program (MSIP), Figure 6: Lava flow on the surface of Mars located near Mount Olympus, a large volcano on mars

The prevalence and multiple occurrences of these specific geological features containing high quantities of energy led us to identifying that utilizing geothermal energy as a stable energy source for Martian colonies is an efficient and feasible method due to the stability, capacity, and abundance of this form of renewable energy. Since the subsurface fluids are heated by the inner mantle on Mars, geothermal energy is almost fully contained within the planet and is not affected by changes in weather patterns[4]. Such conditions allow for geothermal energy to be harvested in normal quantity[6] year round allowing the availability to be stable. In addition, the process of extracting geothermal fluids does not require an extensive amount of energy input to gain an energy output which ensures stable energy prices as well[6]. Furthermore, geothermal energy is highly efficient when it comes to providing the most output with little waste as at least 90% or more of the harvested energy is usable for work [4]. If reservoirs are managed properly and used in moderation (minimize loss of heated fluids), the heat loss can be reduced to a negligible amount. Unlike fossil fuels and coal, geothermal energy comes from subsurface water (which seeps in from the top layer of planetary crust) which boils to steam by the mantle allowing for geothermal heat to be self-replenishable and in large abundance [5]. These observations along with the lava  flows and faults as a source of direct access to subsurface geothermal activity leads us to examine the relationship between elevation and thermal inertia. As elevation decreases, the temperature of geothermal heat rises. Building on this hypothesis, a further point of research that we chose to look at was specifically which sites would be optimally suited for Mars colonization in a way that geothermal energy could be used as the predominant source of renewable clean energy. Based on our hypothesis pertaining to the elevation and the temperature of the geothermal heat, we predicted that the high level of volcanic activity coupled with the formation of ridges near Mount Olympus (see Figure 5) are strong indicators of potential geothermal activity under the surface of Mars.

III. Data Collection

To evaluate our proposed hypothesis, we established our main points of criteria prior to data collection from different locations on the Martian surface. One of our primary criteria was to identify data points that included fault lines (see Figure 6), defined to be a fracture or break in the rocks part of the crust, causing the movement of rock, and usually located near volcanoes and areas with volcanic activity (see Figure 7)[19]. Following this criteria, our second standard was to identify volcanoes, specifically observing how the flow of magma and the formation of the rocks (composed of radioactive decay materials) could lead to the formation of hot springs, features containing high amounts of heat, and how the energy contained within such features could be a potential source utilizing geothermal energy. [1]

Mars Student Imaging Project, Figure 7: Multiple fault lines on the surface of Mars
Mars Student Imaging Project, Figure 8: Olympus Mons, a significant and immense shield volcano

Our third criteria was to identify ridges (Figure 8), or sloped, steep hills that are elevated, specifically to analyze the impact that the elevation had pertaining to the thermal energy that was contained near the ridges. The fourth criteria was to identify troughs (Figure 9), a steep type of rift covering a large area in one direction that is usually found near tectonic activity in order to further analyze the correlation between elevation and thermal energy. Our final criteria was to identify fissures (Figure 10), formed through the flowing magma from the volcano into the widening volcanic dykes and cracks, to identify specific areas related to volcanic activity and potentially high sources of energy.                                      

Based on these five criteria, we specifically chose four testing sites on Mars – Vernal Crater, Arabia Terra (dominant hot spring); Cerberus Fossae, Elysium Quadrangle (prominent fissure); Elysium, Elysium Mons (large volcano); Valles Marineris (large canyon system containing faults and troughs). The data table below identifies these four fields of study that we selected and their respective locations on the planet.

Testing SiteLongitudeLatitude
Vernal Crater335.5oE6oN
Cerberus Fossae166.37 °E11.28 °N 
Elysium Mons147.21oE25.02oN
Valles Marineris59.2oW13.9oS
  Data from JMARS software (2019)

After identifying our criteria and choosing our four fields of study that would include features like fissures, faults, volcanic activity, etc. to collect data, we established our next step: analyze the elevation and the nightside thermal inertia for each site. 
In order to collect data on elevation and nightside thermal inertia, we employed an open-source geospatial information system (GIS) called Java Mission-planning and Analysis for Remote Sensing (JMARS), provided by Arizona State University’s (ASU) Mars Space Flight Facility. JMARS allowed us to scrutinize details of our chosen landforms by rendering remote sensing images from ASU’s orbiters, and overlay multiple variables ranging from surface depth, temperature, topography, and mineral composition into multilayer images[13]. The variable data is sourced from NASA’s orbiters Mars Global Surveyor, Mars Odyssey, and the Mars Reconnaissance Orbiter[13]. Thermal inertia is the measure of a planet’s crust to store heat during daytime and radiate the heat during nighttime. We correlated the data of thermal inertia of the Martian crust, in our specific fields of study, to elevation data, looking for low-lying regions with high thermal inertia, on the hypothesis that the elevation of a particular site shared an inverse correlation with nightside thermal inertia because the lower points of the Martian crust would be closer to the planet’s mantle After this, we generated graphs and reports on the rock composition to analyze the textures of the rock located at each of these regions as a way to confirm the elevation-thermal inertia hypothesis through data as larger rocks located in lower altitudes will have a higher thermal inertia. Our last step was to detect and record the overarching patterns and trends within the data collected for further analysis as a way to establish mathematical relationships between the measured quantities. 

Our first field of study was the Vernal Crater, Arabia Terra, since it is a potential hot spring site on the Martian Surface. Our first graph (Figure 11) compares the elevation to the thermal inertia as the distance increases. The second graph below (Figure 12) compares the rock abundance and the thermal inertia in the same location as the distance increases.

Sanmathi Priya Abiram, Ananya Nagireddy, Smruthi Srinivasan, Figure 12: General trend shows that Elevation (red) decreases and thermal Inertia (blue) increases as distance (km) increases

Figure 13: General trend shows that Rock Abundance (red) decreases then remains low and thermal Inertia (blue) increases then decreases as distance (km) increases

Our second field of study was Cereberus Fossae, Elysium Quadrangle, as this region has a major fissure that formed due to volcanic activity and goes through lava that existed earlier. The first graphical representation (Figure 13) compares the elevation of this region to the thermal inertia, as the distance increases. The second graphical (Figure 14) representation compares the rock abundance with the thermal inertia as the distance increases.

Sanmathi Priya Abiram, Ananya Nagireddy, Smruthi Srinivasan, Figure 14: General trend shows that Elevation (red) and thermal Inertia (blue) display a similar pattern as distance increases

Sanmathi Priya Abiram, Ananya Nagireddy, Smruthi Srinivasan, Figure 15: General trend shows that Rock Abundance (red) remains constant till about 65km and greatly drops. Inertia (blue) increases and decreases in irregular patterns as distance increases.

Our third field of study was Elysium Mons, one of the major volcanoes on the Martian surface. Our first graphical representation (Figure 15) compares the elevation and thermal inertia as the distance increases. Our second graph (Figure 16) compares the thermal inertia and the rock abundance as the distance increases.

Sanmathi Priya Abiram, Ananya Nagireddy, Smruthi Srinivasan, Figure 16: Elevation (red) shows a parabolic trend of the volcano. Thermal Inertia (blue) displays a general constant increase.

Sanmathi Priya Abiram, Ananya Nagireddy, Smruthi Srinivasan, Figure 17: Rock Abundance (red) shows periodic trends of remaining constant, increase and gradual overall decrease after 75 kilometers. Thermal Inertia (blue) displays increase and decrease in irregular patterns.

Our fourth field of study was the Valles Marineris as it was a significant group of canyons that potentially formed through tectonic activity on the planet. Our first graph (Figure 17) compares the elevation with the thermal inertia as the distance increases. Our second graph (Figure 18) compares the rock abundance with the thermal inertia as the distance increases.

Sanmathi Priya Abiram, Ananya Nagireddy, Smruthi Srinivasan, Figure 18: General trend shows that Elevation (red) and thermal Inertia (blue) display a similar irregular pattern of periodic increase and decrease as the distance increases.

Sanmathi Priya Abiram, Ananya Nagireddy, Smruthi Srinivasan, Figure 19: General trend shows that Thermal Inertia (blue) shows an irregular increase and decrease as distance increases. Rock Abundance (red) displays a different irregular pattern of periodic plateaus, increase and decrease as the distance increases.

IV. Conclusion

 From the data samples based on elevation, thermal inertia, and rock abundance, we drew two conclusions from the research which set the trend for future research based on our method. Initially, we hypothesized that the elevation of a particular site shared an inverse correlation with nightside thermal inertia because the lower points of the Martian crust would be closer to the planet’s mantle, thus the particular site would store and radiate more heat. We were able to produce evidence supporting our prediction: at every blue line peak the red line would inversely correlate with the blue line and would have a low point which indicated that when elevation was at its lowest (red line), the thermal inertia would be at its highest (blue line). We observed this pattern in the rest of our data we collected so far. This conclusion indicated that regions oriented near features like fissures and volcanic activity contained high amounts of energy that could be utilized as a source for geothermal energy. 

          We were also able to form a second prediction based on our observations of the relationship between thermal inertia and rock abundance. As rock abundance increases, so does its surface area, thus it would have a high potential for heat storage: in essence, a direct correlation between thermal inertia and rock abundance. This is generally supported in our graphs as the blue lines (thermal inertia) tend to be at its peaks while the red lins (rock abundance) were also at their peaks. The direct correlation between the rock abundance and the thermal inertia goes along with our predictions proving that areas with greater rock area would better retain heat of geothermal energy. 

We were also wary of the potential irregularities in our data such as outliers, for example figure 15, that could affect our analysis. In order to maintain accuracy, we based our analysis on the qualitative, general  trend of the data sets. However, we had to make an assumption about the behavior of Martian lava flows and faults by applying knowledge from external sources, Earth landforms, to develop our hypothesis. As a result, there could have been additional factors of the Martian crust that we did not take into account when analyzing the correlation between thermal inertia and elevation that resulted in outlier data. Furthermore, the outliers we observed occurred at the higher extremity of elevation which led us to believe that it could have resulted due to varying mineral compositions over different elevation which impacted thermal inertia. 

Given that the surface temperature of Mars, near the poles, can drop to -73oC in the summer and  -125oC in winter, Geothermal energy is a potential heat source that can be used to maintain stable and habitable temperatures for future human settlement[20]. Our research provides deeper insight into harvesting geothermal energy on mars as it is a clean and renewable source that can sustain initial human civilizations on Mars.

We would like to thank Mr. Don Boonstra for his support with our research. We would like to conclude by giving a special thank you to Dr. Dale Gary, Professor at New Jersey Institute of Technology, for continuously assisting and supporting us with our research.


References

[1] “Ancient Supervolcanoes Revealed on Mars.” Nature News, Nature Publishing Group, www.nature.com/news/ancient-supervolcanoes-revealed-on-mars-1.13857.

[2] “Drilling Complete on Australian Hot Dry Rock Project.” Energy.gov, www.energy.gov/eere/geothermal/articles/drilling-complete-australian-hot-dry-rock-project.60).” HiRISE, hirise.lpl.arizona.edu/ESP_039485_1660

[3] “Geothermal Energy.” Alliant Kids – Geothermal Energy

www.alliantenergykids.com/RenewableEnergy/GeothermalEnergy.

[4] “Geothermal Energy Information and Facts.” Information and Facts | National Geographic, 17 June 2019, 

www.nationalgeographic.com/environment/global-warming/geothermal-energy/.

[5] “Geothermal Energy.” Technology – RenewableEnergyWorld.com

www.renewableenergyworld.com/geothermal-energy/tech.html. 

[6] “How Geothermal Energy Works.” Union of Concerned Scientists

www.ucsusa.org/clean_energy/our-energy-choices/renewable-energy/how-geothermal-energy-works.html.

[7] “Lava Flows.” Mars Lava Flows | Exploring the Planets | National Air and Space Museum

airandspace.si.edu/exhibitions/exploring-the-planets/online/solar-system/mars/surface/volcanoes/l Ava-flows.cfm.

[8] “Mars Education: Developing the Next Generation of Explorers.” Mars Education | Developing the Next Generation of Explorers, marsed.asu.edu/mep/583.

[9] Morford, Stacy, and Stacy Morford. “Creating Earthquake Heat Maps: Temperature Spikes Leave Clues in the Rock.” State of the Planet, 19 Dec. 2016, blogs.ei.columbia.edu/2016/12/16/creating-earthquake-heat-maps-temperature-spikes-leave-clues-in-the-rock/.

[10] “MSIP: Welcome to the Mars Student Imaging Project.” MSIP: Welcome to the Mars Student Imaging 

Project | Mars Education, marsed.mars.asu.edu/msip.

[11] National Geographic Society. “Crater.” National Geographic Society, 9 Oct. 2012, 

www.nationalgeographic.org/encyclopedia/crater/.

[12] National Geographic Society. “Dune.” National Geographic Society, 9 Oct. 2012, 

www.nationalgeographic.org/encyclopedia/dune/.

[13] “Quick Overview.” JMARS, Mars Space Flight Facility, Arizona State University, 2006, 

jmars.asu.edu/getting-started.

[14] “Volcanic Dike Spawns Giant Flood.” Volcanic Dike Spawns Giant Flood | Mars Odyssey Mission THEMIS

themis.asu.edu/node/5745. 

[15] “What on Mars Is a High Thermal-Inertia Surface? (ESP_039485_1660).” HiRISE, www.uahirise.org/ESP_039485_1660.

[16] National Geographic Society. “Calderas.” National Geographic Society, 4 Apr. 2019, www.nationalgeographic.org/encyclopedia/calderas/.

[17] National Geographic Society. “Types of Calderas.” National Geographic Society, 9 Oct. 2012, www.nationalgeographic.org/article/types-calderas/.

[18] “Cerberus Fossae Fissures (PSP_005720_1885).” HiRISE, hirise.lpl.arizona.edu/PSP_005720_1885.

[19] What is a fault and what are the different types? (n.d.). Retrieved August 17, 2020, from https://www.usgs.gov/faqs/what-a-fault-and-what-are-different-types  

[20] Sharp, Tim. “What Is the Temperature on Mars?” Space.com, Space, 30 Nov. 2017, www.space.com/16907-what-is-the-temperature-of-mars.html.