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| Fig. 1: An artist's rendition of a Kilopower grid on Mars. [3] (Courtesy of NASA) |
Recent advancements in nuclear power have changed the dynamic of our thoughts on travel to mars. Related advancements in space exploration - like SpaceX's recent exploration into larger, cheaper rockets - have also made the idea of moving on to Mars a more serious possibility. Articles like Julian Villalpando's, "Nuclear Space Propulsion" and Alexandra Crerend's, "Radioisotope Thermoelectric Generators (RTGs)" explore the use of nuclear power as a means of rocket propulsion to transcend the moon's borders and as a basic energy source in space. [1,2] An interesting related issue is the issue of generating enough energy for a civilization once on Mars.
A NASA project titled "Kilopower" (see Fig. 1) has been funded by NASA's technology development branch for three years now, "with the aim of demonstrating the system at the Nevada National Security Site near Las Vegas." [3] The goal of the Kilopower project is to build and test a small fission reactor. Tests completed in September 2017 showed that this project's prototype system has been successful. [4] This project could, "provide up to 10 kilowatts of electrical power continuously for at least 10 years. . . enough to run two average households." [4] A settlement on Mars would require large scale energy production to produce necessities like "fuel, air and water, as well as running the habitat and recharging batteries for rovers and science equipment." [3] Similar nuclear batteries have had a maximum power of 240 watts, so the increase in maximum watts provides huge potential for NASA missions.
Traditionally used nuclear batteries, such as those found in the New Horizons project, " ... utilize heat from the natural radioactive decay of Pu-238 oxide." [2,4] Kilopower's reactors instead use Uranium to harness this heat energy, which can be transported in more abundant quantities than Pu-238, meaning they can provide more energy more reliably. The uncertain climate and conditions of a mars settlement and large amount of energy needed required engineers to develop these new ways to harness energy in a foreign environment. A crucial element these engineers looked for in an energy source is something to handle extreme environments. Mars' environment is notably harsher than something like the Moon's. Mars is known to present dust storms among other environmental hazards. Not only does Kilopower provide this robust energy source that previous generators could not, but Kilopower also does not pose the same risks as the traditional fission reactors we are familiar with today. Kilopower reactors can be launched "cold" and activated upon reaching their destinations, meaning they pose less risk while being transported to their destination. Kilopower does, however, still rely on mechanical rod motion to control the fission reactor, meaning there is still an inherent risk characteristic of fission reactors. [1]
Now that NASA has validated the system, they plan to bring the system to a Mars settlement and test its efficacy in its eventual target environment. As of now, the 10 Kilowatts production is promising, but NASA estimates that human expeditions to Mars will, "require a system capable of generating about 40 kilowatts of power." [3] NASA is also looking to utilize this nuclear power in conjunction with other energy collection methods, like solar power - however this would potentially limit settlements to areas subject to constant sunlight. NASA has also discussed utilizing this new method of power generation to explore previously unexplored areas of the Moon, like the Shackleton Crater, which are not subject to sunlight - making energy scarce. NASA plans to send these reactors to Mars, envisioning sending about four or five small fission reactors to Mars in the coming years. [3]
© Lucas Ege. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] J. Villalpando, "Nuclear Space Propulsion," Physics 241, Stanford Universtiy, Winter 2017.
[2] A. Crerend, "Radioisotope Thermoelectric Generators (RTGs)," Physics 241, Stanford University, Winter 2015.
[3] I. Klotz, "NASA Seeks Nuclear Power for Mars," Scientific American, 30 Jun 17.
[4] K. Korosec, "How NASA Might Sustain Life on Mars and the Moon Using Mini Nuclear Reactors," Fortune, 19 Jan 18.