Generation and Analysis of Correlated Pairs of Photons aboard a Nanosatellite

Progress in quantum computers, and their threat to conventional public-key infrastructure, drives new forms of encryption, including quantum key distribution using entangled photons. Beaming entangled photons to Earth from orbit could provide secure quantum communication over long distances. The authors transform a large, delicate quantum-optics setup into a robust payload for a shoebox-sized CubeSat satellite. Their gear survives the trip to space, and correlated photons are produced and detected aboard the satellite, validating the design---a milestone on the road to a space-based quantum communications network.