Finally, nuclear is not the best solution for colonies on Mars

Des chercheurs de l’université de Californie à Berkeley (États-Unis) viennent de déterminer que l’énergie solaire pourrait être la plus efficace pour soutenir l’exploration de la planète Mars. © Sasa Kadrijevic, Adobe Stock

Go to Mars, that’s good. Moving there is even better. But for all this, it will take energy. Electricity in particular. And as well as on Earth, the question now arises of how to produce it. As on Earth, solar and nuclear each seem to want to pull the blanket to them. Which of the two will emerge victorious? The researchers have their idea.

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The Hawai’i Space Exploration Analog and Simulation (HI-SEAS) is a research station installed at an altitude of some 2,500 meters, in a dome of approximately 110 square meters, on the flanks of the Mauna Loa volcano, in Hawaii. The objective: to simulate the life of human colonists who will go to settle on the Moon or on Mars. Not only to understand how astronauts will be able to interact with each other in difficult conditions, but also to develop the most suitable methods and equipment for living and researching on the Moon and Mars. © HI-SEAS

The experts say it again and again, in the context of global warming that we live, oppose nuclear power generation and renewable electricity generation makes no sense. On Earth anyway. But now the debate has suddenly taken on an unexpected height. By exporting to the planet Mars. While most of the engineers who had worked on the question had validated the nuclear option as the best alternative, researchers at the University of California at Berkeley (United States) reveal today that solar could produce for future Martian colonists all the electricity they would need. For an extended mission and even for a permanent installation on the Red Planet.

Recall that the Nasa has been working for several years on the development of miniature nuclear reactors called kilopower. Reactors that can operate 24 hours a day, 7 days a week. And that engineers today consider safe and effective in supporting exploration roboticsbut also human from Mars.

L’solar energy, it presents itself with a few of the same drawbacks as those we know of on Earth. The electricity thus produced must be stored if it is to be used at night. And on Mars, storms of dust sometimes obscure the sky, covering everything with a red veil. We remember that the rover from NASA Opportunity was forced into a break by one of these storms in 2019.

Energy needs difficult to assess

But researchers at the University of California did not want to stop there. In order to compare the two solutions, they opted for a systemic approach. Considering a mission to mars of 480 days, travel time of approximately 420 days included. Because they do not know exactly what the energy needs of such a mission will be, the physicists built a mathematical model to explore different scenarios. Scenarios including for example the needs for temperature and pressure control, for the production of fertilizer for theAgriculture Mars, for the production of methane which will supply the propellant of the rocket intended for the return to Earth or for the production of bioplastics.

They contrasted these needs with the production possibilities of a nuclear Kilopower and photovoltaic production systems coupled with three storage options. Simple batteries, a production ofhydrogen directly by photoelectrochemical cells or hydrogen production by electrolysis. A hydrogen which could then, as some envisage on Earth, be used to supply fuel cells during the Martian night or during the famous dust storms.

Solar energy could be the most interesting

As a result, on almost half of the Martian surface – especially in the equatorial regions – solar power is finally presented as a more interesting solution than nuclear power. If and only if, however, solar production is coupled with a hydrogen electrolysis system.

A question of efficiency, but above all, of the weight of the solar panels. For a landing site near theequator, for example, the researchers estimate that the total weight of the on-board solar panels — plus the hydrogen storage system — would be around 8.3 tons — for a rocket carrying a 100-ton payload. –, compared to 9.5 tonnes for a Kilopower reactor system. Enough to possibly consider carrying emergency panels. Which would not be possible for the nuclear system. The researchers point out, however, that their work is only valid if we consider recently developed flexible solar panels. Lighter because they do without structures in steel or even glass supports like those traditionally seen on rooftops of our good old Earth.

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