The Russian space agency is preparing an extravagant eperiment with a space mirror that would illuminate sun-starved northern cities and act as a "solar sail," officials said. The Znamya (Banner) experiment is to be launched next February and envisages unfolding a space mirror made of a membrane covered by a metal layer. In theory, the mirror is to work like the moon, reflecting sunlight onto some northern parts of Russia during long Arctic nights.