According to Mars Daily, other scientists have explored the idea of implementing small nuclear reactors to provide the required electricity, due to their reliability and the ability to operate 24/7.

Kilopower type mini nuclear reactors have advanced enough in the past decade, so that NASA considers them to be a great source of energy for robotic or human exploration.

Solar panels could be used to store energy that will be used at night, but even so, their efficiency can be severely reduced by the red dust that is present all over the planet surface.

For example, NASA's Opportunity rover, which is almost 15 years old, stopped working after its solar panels were covered in the red dust following a massive storm in 2019.

In a new study published recently in the journal Frontiers in Astronomy and Space Sciences, researchers compared the two power sources regarding a 480-day mission on the Red Planet involving humans that would come back to Earth at the end of it.

The study showed that for about half of the Martian surface, solar energy is just as efficient, if not more, when compared to nuclear energy, if we were to take into account the weight and the efficiency of solar panels.

This is the case as long as some of the solar energy is used to produce hydrogen in order to power the colonies during night time or a sandstorm.

Aaron Berliner, bioengineering doctoral student at the University of California, Berkeley, said that "photovoltaic energy generation coupled to certain energy storage configurations in molecular hydrogen outperforms nuclear fusion reactors over 50% of the planet's surface, mainly within those regions around the equatorial band."

Long missions require more power

NASA's past estimates regarding the power requirements were only taking into account short missions, measured in a few days, but since the independent US agency and leaders, such as Elon Musk with SpaceX and Jeff Bezos with Blue Origin, are taking into account long-time missions, they also need to come up with power sources that would be good enough to sustain human colonies.

Since the cost of carrying materials from Earth to Mars is measured in the hundreds of thousands of dollars per 450 grams, lightweight is essential.

One of the key uses of power is the production of things like food, rocket fuel, plastic materials and even chemicals, such as medicine.

The researchers that looked into the matter said that without knowing exactly how much power would be required to conduct such a mission, it will be difficult to say which of the viable power sources is the best one to use.

With this in mind, they developed a computerized model or various power supply scenarios in order to test the reliability of both nuclear, and solar power.

Photovoltaic panels have three storage options, one being batteries, and for hydrogen, there are two possibilities. Either obtain hydrogen through electrolysis, or directly through photoelectrochemical cells, which would allow for the hydrogen to be pressurized and stored in a fuel cell for later use.

Photovoltaic power with electrolysis was the most efficient and competitive when put against nuclear power, proving to be more cost-effective per kilogram when compared to nuclear for about half of the planet surface.

Advanced photovoltaic panels save the day

Co-author Anthony Abel said that solar panels are now very efficient at converting solar light into electric energy, although the better panels are still expensive.

Lightweight and flexible solar panels are the best solution, since they are cost-effective and easy to transport when compared to traditional panels.

"The silicon panels that you have on your roof, with steel construction, glass backing, et cetera, just won't compete with the new and improved nuclear, but newer lightweight, flexible panels all of a sudden really, really change that conversation," Abel explained.

He also mentioned that due to their light weight, flexible solar panels can be brought to the colonies in larger numbers, so that they can be replace, if needed.

By contrast, there would be few nuclear reactors brought for the missions, and if one fails, there aren't many replacement options, potentially leaving the colonies dry on electricity.

Aaron Berliner said that "I feel like this paper really stems from a healthy scientific and engineering disagreement on the merits of nuclear versus solar power, and that really the work is just us trying to figure out and settle a bet which I think I lost, based on the configurations we chose in order to publish this. But it's a happy loss, for sure."