Cosmos 1 is a solar sail.
The sail weighs 110 kilograms and is made up of eight triangular petals forming a circular sail 30 metres in diameter and with an area of 600 square metres.
This sail was made using a 5 micron (approx.) polymer film which is metallised on the side facing the Sun. During flight, each petal turns on an axis to capture the Sunlight. The pressure exerted by the sunlight provides permanent acceleration. Fantastic speeds - tens of thousands of km/h - could be reached by space vehicles with this equipment.