Solar power better than nuclear for manned missions to Mars: Study

A new NASA-funded study has found that solar power is better than nuclear for planned settlement sites on Mars, thanks to the high efficiency, lightweight and flexibility of solar cell technology.

The new analysis by scientists at the University of California, Berkeley, uses a systems approach to actually compare solar and nuclear power technologies head-to-head for a six-person extended mission to Mars involving a 480-day stay on the planet's surface.

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," said Aaron Berliner, a UC Berkeley bioengineering doctoral student and one of two first authors of the paper.

According to the researchers, short stays don't require power-hungry processes for growing food, manufacturing construction materials or producing chemicals. However, for longer missions, larger and more reliable sources of power need to be considered.

The researchers pitted a Kilopower nuclear system against photovoltaics with three power storage options: batteries and two different techniques for producing hydrogen gas from solar energy - by electrolysis and directly by photoelectrochemical cells.

Only photovoltaic power with electrolysis was competitive with nuclear power: It proved more cost-effective per kilogram than nuclear over nearly half the planet’s surface.

The main criterion in this analysis was weight. The researchers estimated that for a landing site near the equator, the weight of solar panels plus hydrogen storage would be about 8.3 tons, versus 9.5 tons for a Kilopower nuclear reactor system.

Additionally, their model specifies how to tweak photovoltaic panels to maximize efficiency for the different conditions at sites on Mars.

"Lighter weight means more panels can be transported to Mars, providing backup for any panels that fail. While kilowatt nuclear power plants provide more power, fewer are needed, so if one goes down, the colony would lose a significant proportion of its power," said co-first author Anthony Abel, a graduate student in the Department of Chemical and Biomolecular Engineering. 

The new study is published in the journal Frontiers in Astronomy and Space Sciences. More information can be found here.