Embedded Files
Overview
Overview
Kyra Ulreich and Daniel Metcalf
A reliable source of power will be critical for life on the moon, as it is required for keeping people alive in a hostile environment and pursuing the goals of research and exploration. However, the lunar environment is very different from that of Earth, and the challenges and requirements of power production are not the same. For example, the majority of Earth's power currently comes from the combustion of hydrocarbons [1]. These are not naturally present on the moon and the energy density makes it completely infeasible to power a lunar base long-term with fuel brought from Earth, meaning that this source of power is not an option for the moon.
Many current space missions (as well as past moon missions) have been powered by radioisotope thermoelectric generators (RTGs), which harness the decay energy of a radioisotope. While these may be extremely helpful for the initial setup phase of the moon base, they are not a good option for a long-term lunar base since the lifespan of the RTG is inherently limited by the decay rate. The more power an RTG produces, the faster it runs out.
While the goal of our report is to determine the source of power, not the required amount, it is necessary to find some order-of-magnitude target. NASA has suggested that a lunar base could be expected to demand a few hundred of kilowatts of power [38] but the scale of this base seems to be significantly smaller than our 250-person design. In order to compensate for this, we have decided to scale the required power by an order of magnitude to a few Megawatts. For the purposes of this paper, we will assume a power requirement of 3 MW. Additionally, this power must be available quickly upon arrival.
Of the possible power sources for a long-term lunar habitat, solar power, fusion power, and fission power are the most promising possibilities. We have evaluated all three of them below.
Solar
Solar
Solar power offers a unique set of benefits for use in space. The use of solar panels will not require fueling resupply missions or mining operations due to the fact that energy used comes passively from the sun. For this reason the use of solar panels requires significantly less operating personnel than either form of nuclear power generation. An array of solar panels could be built on earth, packed in a rocket, and assembled relatively quickly on the moon.
The technology for solar panels was being developed as early as the 1880's by Charles Fritts, however the first modern solar panels were developed in 1954 at Bell Labs [17]. The technology has been around for quite some time and is as reliable. Due to the nature of solar panels, there are few points of failure that would lead to disaster. The most significant risk is for the panels to not generate sufficient power due to dust collection, damage, or age.
Despite the benefits of solar panels, there are many downsides to their use on the moon.
One general issue with solar panels is that they only provide power during the day. This already leads to problems on earth, but the lunar day is 708.7 hours [20 ] as opposed to the 24 we see on earth. Night lasts for half of this, about 14.8 earth days, which means that any power needed during this time must be captured during the day and stored. For our estimate, this means that the panels must provide at least 6 MW of power during the day, and be able to store 2.1 GWh of energy.
On earth, the most common form of grid-scale power storage is pumped-storage hydropower, which accounted for 90% of the total global storage in 2020 [19]. Unfortunately, this requires a large volume of liquid water and a stable place to put it, neither of which would be feasibly attainable on the moon.
There are other technologies such as thermal storage, compressed gas storage, and battery storage that can currently store the amount of energy needed for the base. Currently, however, there are very few stations with sufficient storage, and these are massive projects that take years to complete [21]. Based on the current energy density of lithium-ion batteries (one of the most-highly studied options for grid-scale power storage), powering the moon base would require 1.06E+7 kg of batteries. To put this into scale, you would need about 244 Saturn V rockets to move this much mass to the moon [Calculations at bottom of page]. Clearly, this is also not a reasonable option.
While other possibilities for grid-scale power storage are not as clearly understood, the scale of the power needed for the moon base means that it energy storage is a massive problem, possibly even an insurmountable one for the goals of this mission.
Nonetheless, solar power still could have potential for the moon. By strategically locating the moon base, we can bypass the need for substantial power storage. At the poles of the moon, there are possible positions for solar arrays that could allow them to receive sunlight without interruption. This would reduce the required power collection back to 3MW. However, there are still significant problems with using solar panels on the moon.
To start with, the most straightforward problem with solar panels is probably dust. The lunar surface is covered with a very fine dust that will settle on the surface of solar panels over time, cutting their efficiency. Action would need to be taken to mitigate this problem, but there are already several possible solutions such as using electrostatic waves to clear dust without any mechanical moving parts [22].
Second, solar PV panels become less efficient with higher temperature. Being bombarded with sunlight while isolated by a vacuum, overheating will be a significant concern. Concentrated solar power must dispose of even more heat as the temperature differential between the heated working fluid and a colder mass is how it produces power. There are several potential methods for managing the excess heat, and it is less of a problem with solar power than with other sources (thermal management is discussed in more detail under Fission).
Third, a significant amount of material will need to be brought from earth. While lunar regolith contains the necessary materials for solar photovoltaic panels and there are companies pursuing using in-situ production [23], this is not a feasible option for our moon base. These panels are expected to have far lower efficiencies [24] which means that you would need around twice as large an area of panels. Production of such a large number of panels will take a long time and energy, but the base will need to meet its power requirements as quickly as possible to support the population. In-situ development of a concentrated solar thermal power plant would require too much time and power to be useful to a base intended to last for 25 years.
The most important piece of equipment to have put together is the panels. Transporting whole solar panels requires more protective packaging than transporting the pieces, however, it is impractical to attempt to assemble the panels on the moon. It is possible to package pre-assembled solar panels for travel, as many shipping companies have methods of safely and successfully transporting solar panels across the earth [18]. Such methods can be feasibly adapted for space transport. The biggest issue is the cost of launching such a load into space. With current technology, NASA can launch 1 kg into space for $1,500 to $3,000. SpaceX claims to be able to launch 1 kg into space for $20 in the near future [16]. The more reliable data suggests that with current technology, launching sufficient solar panel equipment would cost approximately $26,520,275,000. With optimal positioning it would cost roughly $20,275,000, and with future solar technology it would cost $3,200,000.
There are many different varieties of solar PV systems. Since the initial panels will need to be brought from earth, the mass of the panels is probably the most significant consideration. By this metric, there is a clear winner. The energy density of thin film PVs is an order of magnitude higher than other current technologies, with recent designs producing 28-times more power per kg than conventional panels [25]. With currently available technology, power for the base could be provided with about 8000 kg of thin-film panels, less than 20% of a Saturn V payload. Prototypes have also shown much higher efficiencies [26][27], which could lower this to around 1000 kg. While more resources will be needed to position and connect the panels, this is a very reasonable. Accordingly, a solar PV system could be a very effective solution for providing power to a polar moon base.
So when is solar useful?
The obvious answer is to use solar panels for operations similar to that of mars rovers. For the initial set up of the base it would make the most sense to send solar powered robots to do the construction before a nuclear power set up can be made functional. This also reduces the amount of time humans would need to be present on the moon without a functional base, which in turn reduces the amount of extra equipment needed to be brought.
A small solar array can be set up to store back up power for essential systems in the event one of the major power plants malfunctions. It would likely be better to have a second backup reactor, but solar is a reasonable option.
Ignoring the difficulties of sending enough equipment to the moon, solar would be able to generate enough energy on it's own without needing batteries if it could be placed at the poles. To do this, efficient cooling systems would be needed. It would also be possible to do this with molten salt technology, although for the purposes of this problem, it would need to be explored further.
If significant energy storage technology is developed, a sufficient solar array could be constructed nearly anywhere on the surface of the moon. More research is needed to determine how close battery technology development is to being able to store 3 MW for fourteen days.
Fusion
Fusion
Fusion is the merging of smaller atoms to make a larger atom. The power of stars. The fusion discussed in this project is tritium-deuterium fusion and helium 3 fusion. Topics considered in determining the feasibility of fusion on the moon are the difference and accessibility of fueling, the space a plant would take up, and the energy it would take to get started. Fusion has yet to be implemented into the power generation industry as a reliable power source, and sits at around a four on NASA's technology readiness scale, and will need to be developed further before any of this is relevant [10].
Tritium Deuterium Fusion
Tritium Deuterium Fusion
Most of the energy, roughly 80%, from TD fusion is released with the neutron, theoretically making it one of the most efficient energy sources. The useable energy from this reaction is theoretically 14.07 MeV. [3]
Helium 3 Fuison
Helium 3 Fuison
Helium 3 fusion is also a decent source of energy. The usable energy from helium fusion comes from protium atoms (hydrogen 1 or single protons). In deuterium-helium fusion, there are theoretically 14.68 MeV worth of usable energy, and in helium-helium fusion there are theoretically 12.9 MeV worth of usable energy. [3]
Deuterium
Deuterium
Deuterium is the most naturally abundant of the elements necessary for either of these types of fusion. On average one of every 6420 hydrogen atoms is deuterium. [2]
Tritium
Tritium
Tritium comes from neutrons colliding with lithium. It is radioactive and has a half-life of about twelve years.
Helium 3
Helium 3
The only known source of helium 3 is the radioactive decay of tritium. Tritium has a half life of about twelve years, which is relatively short, but still a decently long time to wait for fuel.
Tritium and Helium 3 Generation
Tritium and Helium 3 Generation
Tritium comes from the neutron activation of lithium 6 [7]. On earth this happens most commonly in CANDU fission reactors where a lithium moderator is used to catch access neutrons to keep the reaction under control [8]. The only known way to get helium 3 is from the radioactive decay of tritium [10].
The use of helium 3 under most circumstances is less practical because there is already a global shortage of it, due to the use of helium 3 in medical diagnostics, as well as fusion and other research [6].
On the moon, there is already a small amount of lithium, which can be converted into tritium or helium 3. Unfortunately lithium is one of the more rare elements, and is at most, present as about 31 parts per million in samples taken from the moon. That being said there is helium 3 present in lunar soil [5]. The lithium that is on the moon is constantly being bombarded with neutrons from the sun. The moon has no atmosphere to shield it from solar radiation, like Earth has, so over time the lithium on the moon has been turned into tritium, which has decayed into helium 3. The abundance of helium 3 on the moon sits at an average of about 35 parts per million [11].
The only natural source of deuterium appears to be from the big bang, as stars use up their own deuterium as soon as they make it. Lithium is very rare, and occurs in the universe at about 18 parts per million [9].
Based on this information, it would easiest and most efficient to use helium 3 - helium 3 fusion. The relative abundance of helium 3 on the moon is the highest, however the energy output per reaction is significantly lower than the energy output for tritium-deuterium or deuterium-helium 3 fusion.
Facilities
Facilities
To run a fusion plant four components are needed. A main reactor facility, a power generation facility, a fuel processing and refinement facility, and a cryogenic facility. No working models for a fusion plant have been designed, only experimental and research facilities have been designed [10].
Inertial Fusion Energy Image credit [15]
Inertial Fusion Energy Image credit [15]
Lasers are focused to a small target made of fuel. Laser fusion requires a large array of lasers. A realistically sized laser chamber takes up about 700 square meters, and requires about 40,000 joules of energy to power [15]. In addition to the laser facility, a cryogenic facility is needed to cool fusion targets (fueling) to around 20 K [10].
Magnetic Fusion Energy image credit: DOE
Magnetic Fusion Energy image credit: DOE
Magnetic fields are used to contain a plasma that sparks and maintains a fusion reaction. Magnetic fusion does not need a large laser array, however due to the fact that magnetic fusion uses super conductors, the cryogenic facility must be nearly twice as large as one used only for target cooling [10].
It may be worth looking into using the surface temperature of the moon at night to reduce the amount of energy required to cool fuel targets and super conductors, as the coolest temperatures on the moon reach around 40 K and the temperature of the targets would need to be between 10K and 20 K. Finding a way to use the cool lunar night temperature could reduce both the energy required and potentially the footprint required.
Current Fusion Research
Current Fusion Research
University of Rochester Lab for Laser Energetics: https://www.lle.rochester.edu/
Oak Ridge National Laboratories: https://www.ornl.gov/directorate/ffesd
ITER: https://www.iter.org/
XCIMER: https://www.xcimer.energy/index.html
Type One Energy: https://typeoneenergy.com/
and more...
Fission
Fission
Fission is the breaking of a large atom into smaller pieces. By creating a sustained fission chain reaction in which the fission of one atom triggers the fission of a second atom and so forth, nuclear fission reactors are able to provide an extremely reliable output of energy. This technology is well understood and used across the earth. The energy density of fission makes it very attractive for lunar applications.
Fission Power on Earth
Fission Power on Earth
Most nuclear power plants on earth use the fission of Uranium-235 to generate their power. The majority of these reactors use water as the coolant (to keep the reactor from overheating and extract the heat for useable energy) as well as the moderator (which slows neutrons enough to initiate fission in U-235). Additionally, some reactors use heavy water, which is water enriched to have a higher concentration of deuterium. [28]. A wide variety of other reactors are used around the world, such as reactors that use Thorium rather than Uranium, and more are currently under development.
Fission Power on the Moon
Fission Power on the Moon
Many of the challenges of nuclear power have been solved on earth, but there are a few that will need special consideration. The greatest of these seem to be consistency and resilience, fuel supply, radiation shielding, waste disposal, and thermal management.
Consistency and Resilience
Consistency and Resilience
Nuclear reactors are currently the most reliable power source by a large margin, operating around 92% of the time at full power. While this is certainly a great quality, power must be supplied with perfect constancy for the lunar habitat to remain habitable. In order to meet this need, it seems wise to power the base with three or more lower-power reactors rather than one higher-power reactor. In this case, if a reactor needs scheduled down time, the base will still have at least 66% of it's standard power, which should at least be enough for survival. Additionally, this gives security against the unlikely event of an accident causing a long-term cessation of power from one of the reactors.
Fuel supply
Fuel supply
There are two options for fueling a nuclear reactor on the moon: Mining fuel on the moon or transporting it from earth.
Both uranium and thorium are relatively abundant in certain areas of the moon with abundances up to 2.1 ppm for uranium and 7.3 ppm for thorium [29], which means that mining for nuclear fuel is quite feasible. However, mining it on the moon does pose certain limitations. Uranium reactors require enrichment to function efficiently. Uranium enrichment is already a difficult process here on earth, so implementing it on the moon is an almost impossible technical challenge. The alternative to enriching Uranium is enriching the moderator. Heavy water reactors function in this way. By increasing the concentration of deuterium, the water becomes a more effective moderator allowing for the use of natural uranium. This is also an insurmountable challenge on the moon due to the rarity of hydrogen and resultant rarity of deuterium.
Thorium, however, is much more promising. Along with being significantly more abundant on the moon than uranium, it does not need any enrichment, only chemical separation [30]. This makes thorium the clear frontrunner for lunar fission with local materials.
The alternative to mining is bringing fuel from earth. Commercial reactors operating with low-enrichment uranium that produce much more power than needed for the moon go up to 2 years between refueling [31], and a smaller reactor will be able to use up its fuel less quickly. Nonetheless, this is still significantly under 25 years, so a reactor running on low-enrichment uranium or thorium would need regular refueling. This would require resupplies from earth, which would be logistically challenging and reduce the base's self-sufficiency and resilience. Instead, the best option for earth-sourced reactor materials would be to implement highly enriched uranium reactors designed to provide power for the entire duration of the moon mission. While this may seem incredibly infeasible, current naval reactors used on submarines can run for at least 33 years [32] with a rumored power output of over 200 Megawatts [33]. Even if this power value has significant error, this is well above the requirements for both power and time. While adaptations to this technology would be required to optimize if for the moon, it would be entirely possible energetically.
Radiation Shielding
Radiation Shielding
Current nuclear power plants use large masses of specially blended concrete for shielding [34]. A lunar fission reactor could be built similarly using sintered regolith, which has been shown to successfully block neutrons with sufficient thickness [42]. An alternative method would be to put the entire reactor into a pit, allowing the unaltered surrounding regolith to block the radiation. In either case, the reactors should be placed far from the habitat to further minimize the risk to the inhabitants.
Waste Disposal
Waste Disposal
Nuclear waste disposal on earth is already a contentious issue, but it could be even more controversial on the moon. The moon is dry and geologically stable [35], which makes it ideal for a deep geological repository [36]. The biggest issue with this plan is the potential for public outcry against 'tarnishing' the moon in this way. Accordingly, this will require input from public relations experts as well as the development of plans for alternative methods of dealing with the waste such as returning it to earth for disposal, leaving it on the surface of the moon, or putting it into solar orbit.
Thermal Management
Thermal Management
Power is generated from a fission reaction from the temperature gradient between the reactor and a colder body used as a heat sink. On earth, most reactors use large bodies of water as heat sinks, but the moon does not have liquid water or even an atmosphere. This makes it a significant challenge to get rid of the reactor's heat and generate power from the heat of the reactor. There are multiple possibilities for solving this problem, but there is also significant dependency on the location of the base.
One method for handling the thermal management will be pumping the heat into a colder substrate. Since the temperature of the moon is around 250 K [37], it would be possible to dissipate the heat into the ground with a sufficient area for heat exchange. However, this would require significant work to set up and lead to significant permanent disturbance to a relatively large area of the lunar surface. A second place to which heat could be vented is the atmosphere of the lunar habitat. This will require significant heating (mostly during the lunar night) so this would be a very effective use of the waste heat. However, it will most likely be unable to provide all of the require cooling.
Radiative cooling is another possibility of interest. It is frequently used for radioisotope thermoelectric generators operating in vacuums, and while it would require a significant surface area, it is an attractive possibility [38]. However, the moon does pose significant challenges to this method of thermal management. Lunar dust lowers the efficiency of the radiators [39]. Additionally, the heat of the lunar day, especially in direct sunlight, reduces the effectiveness of radiative cooling. Accordingly, there must be a system to remove dust, and the radiative cooling must be sufficient to cool the reactor even when the surrounding environment is up to 121 °C, the temperature of lunar days [40]. The direction of the radiators could also be adjusted to keep the area perpendicular to the incoming sunlight, reducing the external heating.
A final option for thermal management is using the heat to melt water ice in certain areas of the moon where there are large deposits, such as the south pole [41] . This heat can melt the ice for use by the inhabitants of the base, meeting multiple needs simultaneously, however, it is an extremely localized option.
The specific thermal management strategy will likely need to be a combination of these methods, developed specifically for the chosen location and reactor design.
Conclusion
Conclusion
Solar
Solar
Solar will be the most useful for starting the building of the base and for any mining or other missions that will take place outside of the base. Solar power is already being used to power Martian robots, so repurposing the idea for lunar off base projects won't be difficult. With current technology, solar is not an efficient source for powering the entire base.
Fission
Fission
Fission is the most practical source of energy due to its high energy density, consistent power output, fuel availability, and relatively simply design and operation.
Fusion
Fusion
Even ignoring the fact that fusion is still in the developmental phases, it is probably not practical to power the moon base with fusion. Fusion requires a large amount of facilities and a huge amount of initial energy. The power required to run all of the necessary fusion facilities is likely nearly greater than or equal to the power required for the base. This means the fusion plant's purpose would ultimately be to power itself, which is fairly inefficient. If the moon base were to expand, a helium 3 fusion plant may be warranted, but as the project stands now, fusion for a project this scale would be redundant.
Sources
Sources
[1] Hannah Ritchie and Pablo Rosado (2020) - “Electricity Mix” Published online at OurWorldInData.org. Retrieved from: 'https://ourworldindata.org/electricity-mix' [Online Resource]
[2] Ma, T., Betti, R., & ect al. (2023). (rep.). Inertial Fusion Energy; Basic Research Needs Workshop. United States Department of Energy. Retrieved from https://acrobat.adobe.com/id/urn:aaid:sc:VA6C2:d06e2938-eb97-4289-8723-caa4f037af8c.
[3] Chapman, J. J. (n.d.). (rep.). Advanced Fusion Reactors for Space Propulsion and Power Systems. NASA. Retrieved from https://ntrs.nasa.gov/api/citations/20110014263/downloads/20110014263.pdf.
[4] Daya, P. (2023, January 13). What is deuterium?. IAEA. https://www.iaea.org/newscenter/news/what-is-deuterium
[5] Dreibus, G., Spettel, B., & Wänke, H. (1977). Lithium and halogens in lunar samples. Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences, 285(1327), 49–54. https://doi.org/10.1098/rsta.1977.0042
[6] Office of Science. (2019, March 11). NP supply and demand of helium-3: U.S. Doe Office of Science (SC). NP Supply and Demand of Helium-3| U.S. DOE Office of Science (SC). https://science.osti.gov/np/Research/IDPRA/3He-Fact-Sheet
[7] Giegerich, T., Battes, K., Schwenzer, J. C., & Day, C. (2019). Development of a viable route for lithium-6 supply of DEMO and future fusion power plants. Fusion Engineering and Design, 146(December 2019). https://doi.org/10.1016/s0920-3796(19)30806-3
[8] Pearson, R. J., Antonazzi, A. B., & Nuttall, W. J. (2018). Tritium supply and use: a key issue for the development of nuclear fusion energy. Fusion Engineering and Design, 131(November 2018), 1140–1148. https://doi.org/10.1016/s0920-3796(18)30464-2
[9] Greenwood, N. N., & Earnshaw, A. (1997). Chemistry of the elements. Elsevier Science & Technology. https://ebookcentral.proquest.com/lib/utk/reader.action?docID=1179847
[10] Personal Communication: Jeff Ulreich, Mechanical Engineer, Oak Ridge National Labs
[11] NASA. (1988). (publication). Lunar Helium-3 and Fusion Power. Retrieved 2024, from https://ntrs.nasa.gov/api/citations/19890005471/downloads/19890005471.pdf.
[12 ]Tartèse, R., Anand, M., Barnes, J. J., Starkey, N. A., Franchi, I. A., & Sano, Y. (2013). The abundance, distribution, and isotopic composition of hydrogen in the Moon as revealed by basaltic lunar samples: Implications for the volatile inventory of the Moon. Geochimica et Cosmochimica Acta, 122(1 December 2013), 58–74. https://doi.org/10.1016/j.gca.2013.08.014 https://www.sciencedirect.com/science/article/pii/S0016703713004584#s0020
[13] Shaw, D. M. (1995). Lunar behaviour of boron contrasted with the terrestrial boron cycle. Meteoritics, 30(2), 199–208. https://doi.org/10.1111/j.1945-5100.1995.tb01114.x
[14] Yamashita, N., et al. (2010), Uranium on the Moon: Global distribution and U/Th ratio, Geophys. Res. Lett., 37, L10201, doi:10.1029/2010GL043061. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010GL043061
[15] The University of Rochester. (2021, June 16). Omega Laser Facility. Laboratory for Laser Energetics. https://www.lle.rochester.edu/omega-laser-facility-2/
[16] Jones, H. W. (2023). (tech.). Take Material to Space or Make It There? NASA. Retrieved 2024, from https://ntrs.nasa.gov/api/citations/20230013555/downloads/Take%20or%20Make%20in%20space.pdf.
[17] Duval, G. (2024, February 12). When were solar panels invented?. Today’s Homeowner. https://todayshomeowner.com/solar/guides/when-were-solar-panels-invented/#:~:text=The%20first%20modern%20solar%20panel,that%20it%20wasn’t%20practical.
[18] Heavy Haulers. (2023). Shipping solar panels: Solar panel transport: Heavy haulers. Shipping Solar Panels | Solar Panel Transport | Heavy Haulers. https://www.heavyhaulers.com/solar-panel-shipping.php
[19] Iea. (2023). Energy storage. IEA. https://www.iea.org/energy-system/electricity/grid-scale-storage
[20] Ladd, D., Petro, N., & Wright, E. (2023, May 3). NASA Scientific Visualization studio. NASA. https://svs.gsfc.nasa.gov/12739/#:~:text=A%20mean%20solar%20day%20on,2017%20are%20mean%20lunar%20days
[21] Progressive Media International. (n.d.). Moss Landing Battery Storage Project, California, US. NS Energy. https://www.nsenergybusiness.com/projects/moss-landing/
[22] Kawamoto, H., Uchiyama, M., Cooper, B. L., & McKay, D. S. (2011). Mitigation of lunar dust on solar panels and optical elements utilizing electrostatic traveling-wave. Journal of Electrostatics, 69(4), 370–379. https://doi.org/10.1016/j.elstat.2011.04.016
[23] Fingas, J. (2023, February 13). Blue Origin made solar cells by smelting simulated Moon Dust. Engadget. https://www.engadget.com/blue-origina-solar-cells-moon-soil-173908801.html
[24] Ellery, A. (2021). Generating and storing power on the moon using in situ resources. Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, 236(6), 1045–1063. https://doi.org/10.1177/09544100211029433
[25] Saravanapavanantham, M., Mwaura, J., & Bulović, V. (2022). Printed Organic Photovoltaic Modules on transferable ultra‐thin substrates as additive power sources. Small Methods, 7(1). https://doi.org/10.1002/smtd.202200940
[26] Scarpulla, M. A., McCandless, B., Phillips, A. B., Yan, Y., Heben, M. J., Wolden, C., Xiong, G., Metzger, W. K., Mao, D., Krasikov, D., Sankin, I., Grover, S., Munshi, A., Sampath, W., Sites, J. R., Bothwell, A., Albin, D., Reese, M. O., Romeo, A., … Hayes, S. M. (2023). CdTe-based thin film photovoltaics: Recent advances, current challenges and future prospects. Solar Energy Materials and Solar Cells, 255, 112289. https://doi.org/10.1016/j.solmat.2023.112289
[27] Thin-film solar panels. American Solar Energy Society. (n.d.). https://ases.org/thin-film-solar-panels/
[28] Nuclear Power Reactors | How does a nuclear reactor work?. World Nuclear Association. (2023, May). https://world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-power-reactors/nuclear-power-reactors.aspx
[29] Yamashita, N., Hasebe, N., Reedy, R. C., Kobayashi, S., Karouji, Y., Hareyama, M., Shibamura, E., Kobayashi, M. ‐N., Okudaira, O., d’Uston, C., Gasnault, O., Forni, O., & Kim, K. J. (2010). Uranium on the Moon: Global Distribution and u/th ratio. Geophysical Research Letters, 37(10). https://doi.org/10.1029/2010gl043061
[30] Schaffer, M. B. (2013). Abundant thorium as an alternative nuclear fuel. Energy Policy, 60, 4–12. https://doi.org/10.1016/j.enpol.2013.04.062
[31] U.S. Energy Information Administration. (n.d.). U.S. nuclear plant outages increased in September after remaining low during summer - U.S. energy information administration (EIA). U.S. Energy Information Administration (EIA). https://www.eia.gov/todayinenergy/detail.php?id=37252#:~:text=A%20scheduled%20shutdown%20of%20a,when%20electricity%20demand%20is%20lower.
[32] Director, N. N. P. (1995, June). Report on Use of Low Enriched Uranium in Naval Nuclear Propulsion. https://fissilematerials.org/library/onnp95.pdf
[33] Pike, J. (n.d.). S9G Next Generation Reactor High Energy Density Core. GlobalSecurity.org. https://www.globalsecurity.org/military/systems/ship/systems/s9g.htm
[34] Kanagaraj, B., Anand, N., Diana Andrushia, A., & Naser, M. Z. (2023). Recent developments of radiation shielding concrete in nuclear and radioactive waste storage facilities – a state of the Art Review. Construction and Building Materials, 404, 133260. https://doi.org/10.1016/j.conbuildmat.2023.133260
[35] Jaumann, R., Hiesinger, H., Anand, M., Crawford, I. A., Wagner, R., Sohl, F., Jolliff, B. L., Scholten, F., Knapmeyer, M., Hoffmann, H., Hussmann, H., Grott, M., Hempel, S., Köhler, U., Krohn, K., Schmitz, N., Carpenter, J., Wieczorek, M., Spohn, T., … Oberst, J. (2012). Geology, geochemistry, and geophysics of the moon: Status of current understanding. Planetary and Space Science, 74(1), 15–41. https://doi.org/10.1016/j.pss.2012.08.019
[36] McCombie, C., Pentz, D. L., Kurzeme, M., & Miller, I. (2000, November 19). Deep Geological Repositories: A safe and secure solution to disposal of nuclear wastes. OnePetro. https://onepetro.org/ISRMIS/proceedings/IS00/All-IS00/ISRM-IS-2000-015/50923
[37] Langseth, M.G., Clark, S.P., Chute, J.L. et al. The Apollo 15 lunar heat-flow measurement. The Moon 4, 390–410 (1972). https://doi.org/10.1007/BF00562006
[38] NASA. (1992, January 1). Space Resources. volume 2: Energy, power, and Transport - NASA Technical Reports Server (NTRS). NASA. https://ntrs.nasa.gov/citations/19930007716
[39] NASA. (2022, April). RTG radiator efficiency in the presence of lunar dust - NASA technical reports server (NTRS). NASA. https://ntrs.nasa.gov/citations/20220005147
[40] NASA. (n.d.). Weather on the Moon. NASA. https://science.nasa.gov/moon/weather-on-the-moon/
[41] Your guide to water on the Moon. The Planetary Society. (2022, August 6). https://www.planetary.org/articles/water-on-the-moon-guide#:~:text=How%20much%20water%20is%20on,240%2C000%20Olympic%2Dsized%20swimming%20pools.
[42] Meurisse, A., Cazzaniga, C., Frost, C., Barnes, A., Makaya, A., & Sperl, M. (2020). Neutron radiation shielding with sintered lunar regolith. Radiation Measurements, 132, 106247. https://doi.org/10.1016/j.radmeas.2020.106247
Minor sources:
Technology readiness level: https://www.nasa.gov/directorates/somd/space-communications-navigation-program/technology-readiness-levels/
Asteroid composition:
https://nineplanets.org/c-type-asteroids/
https://science.nasa.gov/solar-system/asteroids/facts/
Page updated
Report abuse