If it sometimes feels as if the world is awash in advertisements, just wait. A Russian startup just revealed plans to use swarms of tiny, light-reflecting satellites to create sprawling billboards in space.

The first of StartRocket's space-based ads, shown in a new concept video released by the company last week, could go up by 2021. The ads — a bit like skytyping, only in low-Earth orbit rather than in the atmosphere — would be visible only at night but could be seen from just about anywhere on the planet.

The ads would be created by an array of tiny satellites, each equipped with a reflective sail about 30 feet in diameter. As these "cubesats" orbit at an altitude of about 280 miles, sunlight would reflect off the sails to form luminous words or logos visible from the ground below.