  Extending quantum communication to Space environments would enable to perform
fundamental experiments on quantum physics as well as applications of quantum
information at planetary and interplanetary scales. Here, we report the first
experimental implementation of a scheme for single-photon exchange between a
satellite and an Earth-based station. We built an experiment that mimics a
single photon source on a satellite, exploiting the telescope at the Matera
Laser Ranging Observatory of the Italian Space Agency to detect the transmitted
photons. Weak laser pulses, emitted by the ground-based station, are directed
towards a satellite equipped with cube-corner retroreflectors. These reflect a
small portion of the pulse, with an average of less-than-one photon per pulse
directed to our receiver, as required for the faint-pulse quantum
communication. We were able to detect returns from satellite Ajisai, a
low-earth orbit geodetic satellite, whose orbit has a perigee height of 1485
km.
