Cosmos 1 consists of a 110-kilogram spacecraft with eight triangular solar sails which, once deployed, give it a diameter of 30 m, for a total area of ​​approximately 600 m2. The eight sails are made of mylar, a polymer, very thin, very light and very reflective.

The duration of the mission wasn't supposed to exceed one month after the launch, as the mylar degrades with the solar rays.

Cosmos 1 used the radiation pressure induced by the Sun to move in space. Although it is very weak in comparison with that produced by conventional propulsion means (chemical propulsion), this pressure is continuous and lasts in time. As in space there is practically no resistance to the movements of objects, the speed only increases. And so, for long trips such as those to Mars or further, the time taken by a solar sail is shorter than that with a chemical propelled engine. This mode of propulsion is to be compared with the ionic propulsion, a weak force, but a continuous force and long in duration.