A research team have analysed different ways of generating power, deciding that solar energy could be used to power a mission to Mars.
It can be argued that no other planet in our Solar System has sparked human interest and imagination more than Mars. While modern science has debunked the Red Planet as a likely source of an alien invasion, today’s technology is bringing us closer to a crewed mission. A research team out of the University of California, Berkeley, published a paper in the journal Frontiers in Astronomy and Space Sciences, that argues that a crewed mission to Mars’ surface could be powered by harvesting solar energy.
This is not a novel concept, as the main source of power for a number of NASA Mars rovers originates from a multi-panel solar array. However, in the last decade, the majority of people had assumed that nuclear power would be a better option than solar energy for human missions to Mars, according to co-lead author Aaron Berliner, a bioengineering graduate student in the Arkin Laboratory at UC Berkeley.
Comparing different methods to generate power
What makes this current study unique is how the researchers compared various ways to generate power. The calculations took into account the amount of equipment mass that would be required to be transported from Earth to the Martian surface for a six-person mission to Mars. Specifically, they quantified the requirements of a nuclear-powered system against different photovoltaic and even photoelectrochemical devices.
While the energy output of a miniaturised nuclear fission device is location-agnostic, the productivity of solar-powered solutions relies on solar intensity and surface temperature, amongst other factors that would determine where a non-nuclear outpost would be optimally located. This required modelling and accounting for a number of factors, such as how gasses and particles in the atmosphere might absorb and scatter light, which would affect the amount of solar radiation at the planet’s surface.
The most successful avenue was using a photovoltaic array that utilises compressed hydrogen for energy storage. At the equator, what the researchers labelled the ‘carry-along mass’ of such a system is about 8.3 tons versus approximately 9.5 tons for nuclear power. The solar-based energy system becomes less tenable closer to the equator at more than 22 tons, yet it exceeds over fission energy across about an estimated 50% of the Martian surface.
Solar based energy system
“I think it is nice that the result was split pretty close down the middle,” Berliner explained. “Nearer the equator, solar wins out; nearer the poles, nuclear wins.”
Such a system can employ electricity to split water molecules to produce hydrogen, which can be stored in pressurised vessels and then re-electrified in fuel cells for power. Other applications for hydrogen include combining it with nitrogen to produce ammonia for fertilisers – a common industrial-scale process.
Other technologies, such as water electrolysis to produce hydrogen and hydrogen fuel cells, are less common on Earth, largely due to costs, but are potentially game-changing for a human mission to Mars.
“Compressed hydrogen energy storage falls into this category as well,” noted co-lead author Anthony Abel, a chemical and biomolecular engineering PhD student at UC Berkeley. “For grid-scale energy storage, it’s not used commonly, although that is projected to change in the next decade.”
Space exploration and achieving a mission to Mars
Both Abel and Berliner are members of the Center for the Utilisation of Biological Engineering in Space (CUBES), a project developing biotechnologies to support space exploration. For example, CUBES is focused on engineering microbes to make plastics from carbon dioxide (CO2) and hydrogen or pharmaceuticals from CO2 and light.
The new paper establishes a baseline for the electricity and hydrogen budget that would enable these sorts of applications.
“Now that we have an idea of how much power is available, we can start connecting that availability to the biotechnologies in CUBES,” Berliner said. “The hope is ultimately to build out a full model of the system, with all of the components included, which we envision as helping to plan a mission to Mars, evaluate trade-offs, identify risks, and come up with mitigation strategies either beforehand or during the mission.”
Beyond science and technology, Abel said it is important to consider the human element of space exploration as well. “To quote Chanda Prescod-Weinstein, ‘Our problems travel into space with us.’ So, when we think about going to Mars, we also have to think about how to address problems like racism, sexism, and colonialism, to make sure we go to Mars in the ‘right’ way,” concluded Abel.