Experimental verification of the feasibility of a quantum channel between space and Earth

Extending quantum communication to space environments wouldenable us to perform fundamental experiments on quantum physics as well asapplications of quantum information at planetary and interplanetary scales. Here,we report on the first experimental study of the conditions for the implementationof the single-photon exchange between a satellite and an Earth-based station.Webuilt an experiment that mimics a single photon source on a satellite, exploitingthe telescope at the Matera Laser Ranging Observatory of the Italian SpaceAgency to detect the transmitted photons. Weak laser pulses, emitted by theground-based station, are directed toward a satellite equipped with cube-cornerretroreflectors. These reflect a small portion of the pulse, with an average of lessthan-one photon per pulse directed to our receiver, as required for faint-pulse