The smallest packages of energy in what we know as light are called photons. When photons strike the surface of an object some or all of the frequencies of energy are absorbed while the rest is reflected. This action can be harnessed to create motion just from the pressure of the reflected light.
In this video, a home experimenter builds a small light powered turbine that illustrates this principle. Could this be scaled up to be useful technology in space or even here on earth?