Tiny crystals of pyrite energy are expected to be a source of power on the moon in the future

A pyrite-based crystal, only a hundredth of a millimeter in size, could serve as a light-absorbing layer for tiny solar cells — perhaps a promising future power source on the moon. ESA has collaborated with the Tallinn University of Technology (TalTech) in Estonia to research and produce microcrystalline coils that look like sandpaper as the base material for single-crystalline solar cells.

"We are studying the role of these microcrystals in future lunar settlement," explains Advenit Makaya, an ESA advanced manufacturing engineer. "The future lunar base will need to 'feed on the sky' for sustainable development, and the iron and sulfur needed to produce pyrite can be obtained directly from the lunar surface."

Dr. Taavi Raadik of TalTech explains. "Our goal is to develop pyrite microcrystalline growth technology and use it for single-crystalline solar cells, where each tiny crystal will work as a separate solar cell. A tiny solar cell generates very little electricity, but in a normal-sized module, there will be billions of such cells – and in principle there are no limits in size and shape. In addition, our goal is that all necessary source materials should be available for in-situ collection on the Moon. "

TalTech's PhD student Katriin Kristmann's work on this topic is co-sponsored by TalTech and ESA's Discovery and Preparation Project. She explained. "We are delighted to be working with this very ambitious project. Through this partnership, we will have the opportunity to bring science from Estonia to the moon."

The project will include giving Katriin the opportunity to conduct a detailed study of crystal quality using ESA's laboratory facilities at the ESTEC Technical Center in the Netherlands.

"This is just one of a range of in situ resource utilization methods that ESA has been working on for the Moon or beyond," Advenit added.

The power supply is an important factor in choosing the location of a future lunar base. For example, the moon's south pole is favored because there are adjacent "near-eternal peaks of light" that provide almost sustained access to solar energy, and at lower lunar latitudes, settlers will have to contend with two weeks of long nights.