In the early 1990s, NASA was planning for an extended stay on Mars, and Bubenheim and his Ames colleagues were concentrating efforts on creating a complete ecological system to sustain human crewmembers during their time on the Red Planet.
“The main barrier to developing such a system,” he says, “is energy.” Mars has no power plants, and a regenerative system requires equipment that runs on electricity to do everything from regulating humidity in the atmosphere to monitoring the quality of recycled water. The Ames group started looking at maximizing energy use efficiency and alternative methods to make power on a planet that is millions of miles away from Earth. They turned to a hybrid concept combining two renewable sources: wind and solar power technologies. Large surface temperature swings on Mars produce windy conditions; extreme examples are the frequent dust storms that can block nearly all sunlight. “When there’s a dust storm and the wind is blowing, the wind system could be the dominant power source. When the wind is not blowing and the sun is shining on the surface, photovoltaics could be the dominant source,” says Bubenheim.