In one of the first experiments to take place on the outside of the International Space Station (ISS), a new type of 3D-textured solar cell will soak up 16 sunrises everyday from the “back porch” of the orbiting research vessel. The carbon nanotube cell was designed by Georgia Tech Professor W. Jud Ready, and it features an experimental 3D coating that “traps” light. In Earth-based tests the next-gen solar cells have yielded a greater efficiency than conventional flat solar cells.
The 16 sunrises that the 3D-textured solar cells will encounter each day will provide a significant test for the cells key efficiency-enhancing attribute. Coated with a copper-zinc-tin-sulfur mixture, the cells appear as “millions of tiny skyscrapers when viewed under a microscope,” providing a texture which enables the cells to trap sunlight, rather than having the light reflect off the cells, as is the case with standard 2D, flat solar cells.
As a result, while flat solar panels often under-perform at sunset, Ready’s textured cells actually prove more efficient at this time, as sunlight hits the coating at a sharper angle. Tests on earth have so far supported the 3D-textured cells efficiency improvements over conventional flat cells.
Speaking to Tech News Daily, Ready explained that the ISS tests, which are administered by the Center for the Advancement of Science in Space (CASIS), will help to quickly amass data as to the cells’ performance in a huge variety of light conditions. “If you were to go through all the possible configurations on Earth, it would be very challenging,” but as the ISS orbits the earth every one-and-a-half hours, the cells will be bombarded by light from all directions.
The test is expected to last a few months, with the cells expected to expire under harsh wind conditions and extreme temperatures that oscillate between 250 degrees Fahrenheit and minus 250 degrees Fahrenheit, while also being vulnerable to micrometorite impacts. But Ready explains “In my proposal… I said to leave them up there until they all failed.” The test is expected to begin sometime next year.