Znamya-2, the first and so far only mirror to fly in space and reflect sunlight back to Earth. Syromyatnikov thought space mirrors could extend the Russian agricultural season and perhaps be used to carve channels through polar ice sheets. From space, cosmonauts reported seeing a faint circle of light race over the Earth’s surface at tremendous speed. Znamya-2.5 held a far bigger mirror and was supposed to shine ten times brighter than the full moon. Space observatories are powerful, but expensive and far from able to replace what we do from the Earth’s surface.