Solar power and dirt are at the heart of an idea for a potential electrical power source on the moon. Alex Ignatiev, Director of the Center for Advanced Materials, University of Houston, is the brain power behind the idea. The solar cell paver still holds his interest despite the fact that the project is currently quiet, owing to funding issues.
“We completed a proof of concept for the system,” he said, “and started engineering design."
Basically, the system uses a mobile robot to scoop moon regolith. The robot passes it along to processing chambers that, via a silicon and metals extractor, transform the regolith into solar cell raw materials, including silicon. Then, exploiting the vacuum of space for chemical deposition, it "paves" thin-film solar cells and interconnects directly onto the moon's surface.
"In a year," Ignatiev said, "we could be generating 200 kW of power—in five years, a megawatt.”
The system obviates the need to transport thousands of solar cells across many flights. “In place of bringing finished product, why not just bring the tool and materials?” Ignatiev asked. “In the exploration of space, you need three things. The first is energy. The second is energy. And the third is energy. If you can fabricate your energy generation from materials in space, you gain on all fronts. We’re hoping we can pick this up again as the scientific side of space regains funding.”
Ignatiev has picked up where earlier research around manufacturing in space left off. “There was talk of manufacturing in space 20 or 30 years ago,” he said, “but the logistics are against it. Conceptually speaking, there just are not enough cost-effective delivery trucks to make distribution feasible. But we did learn a lot about thin-film epitaxial deposition and have applied what we learned to terrestrial manufacturing.”
Ignatiev’s center is working on one project in particular: development of high-efficiency solar cells. “The moon paver makes basic, low-efficiency cells,” he said, “but we’ve made 40% efficient cells that have been tested in orbit—very high-quality, exotic materials are involved. In doing that, we think we see ways to reach 50, 60, 70% efficiency.”
Working in collaboration with the Space Research Institute of the Russian Academy of Sciences, which offers regular space expeditions, Ignatiev’s team has enjoyed ongoing opportunities to gain information. “The main benefit is in orbit operations, the vacuum environment, and process pumping speeds,” he said. “It’s allowed us to tweak our terrestrial systems and to determine whether problems stem from contamination or from wrong concepts.”
While expanded funding is not a given at this point, it looks as though progress in materials with an eye on space will continue—even if resources are difficult to come by.