American scientists have investigated the most efficient way to generate energy during a long stay on the red planet.

Suppose we finally send astronauts to Mars in x number of years. And not to take a walk there and collect some stones, but for a stay of more than a year. Then those astronauts will have to generate energy on the spot. But how? That investigated Anthony Abel, Aaron Berliner and colleagues from the University of California at Berkeley.

The two main options were a small nuclear reactor and solar panels. A point of contention between the lead researchers: Berliner went into the study with a preference for nuclear energy, while Abel was more interested in solar energy. You could describe the result as a draw: solar panels are the best option for about half of the Martian surface, for the other half it is better to take small nuclear reactors with you.

Lightweight and flexible

The most important factor is how much the stuff you need to generate energy weighs. You will have to transport all those materials to Mars, at a price of hundreds of thousands of euros per kilogram. And yes, then you do want to know which technique is the lightest.

Solar panels of the type that can be found on more and more houses are then no match for a small nuclear reactor. Much too heavy, because of all the steel and glass that is used in these constructions. But there are now also lightweight, flexible solar panels – and they are an attractive option.

Mini nuclear power plant

It is then important where on Mars you will build your habitat. Near the equator you catch the most sunlight. So you need relatively few solar panels there. For a mission in which six astronauts stay on Mars for 480 days, you could use 8.3 tons of solar panels, according to Abel and Berliner.

The further you move towards one of the poles, the less sunlight reaches the surface and the more solar panels you need to generate enough energy. At worst, in the Martian polar regions, you need about 22.4 tons of solar panels.

A mini-nuclear power plant, on the other hand, just does its thing wherever you put it. And such a device is estimated to weigh about 9.5 tons. At the higher latitudes, a nuclear reactor is therefore the lightest option.

Mars ticket

In the yellow area around the equator of Mars, solar panels are a better option than small nuclear power plants, in the orange part the nuclear power plants win. Illustration: Anthony Abel/Aaron Berliner/UC Berkeley

Hydrogen required

Now, of course, the sun only shines on Mars during the day. In addition, there are dust storms that can cause solar panels to temporarily yield little. That is why it is important to store some of the collected solar energy so that you can use it later. Only if you do this with the help of hydrogen, Abel and Berliner calculate, will the solar panels win in the area around the equator of the nuclear power plants.