heliostat

Originally intended to be an experimental solar sail, the Znamya (Знамя, “Banner”) programme shifted its focus towards artificial illumination and extending day-light hours and thus the potential for photovoltaic power, the second and unfortunately final mission in this series was launched on this day in 1992 aboard a cargo craft during a resupply mission to Mir.
In a very technically complicated and precision operation, once the re-supply ship undocked, the twenty-metre in in circumference mirror was deployed and mounted on the fore of the craft and slowly navigated into position over the course of the months. Its orbit finally aligned with the rising sun on the pre-dawn hours of 4 February 1993, it beamed down the reflected light of the sun—still well over the horizon for terrestrial observers, on patch of Earth with a five kilometre radius with the apparent glow equal to a full Moon (despite the cloudy weather that night) that passed from southwest France to Moscow, the spotlight zooming by at a speed of eight kilometres per second. A follow-on, more ambitious mission in 1999 had to be aborted when the mirror failed to unfurl. Learn more at Amusing Planet at the link above.