NASA Missions Help Identify What Powers Auroral ‘Space Battery’Green auroral arcs extend across the sky in this photo captured in northwestern Canada in 2019. The right arc is a typical auroral arc, while the brighter arc on the left is transforming into another type of aurora with bead-like features. Neil ZellerScouring archived observations from NASA missions, scientists may have solved a mystery about what powers a type of aurora called auroral arcs. A green auroral arc appears above the clouds in this photo taken by an astronaut aboard the International Space Station in 2014. The electric fields work like a “space battery” for the auroral arcs, but scientists weren’t sure what powers that battery.