Fig. 1: Comparison of hybrid and fully space-based quantum repeater architectures.
From: Proposal for space-borne quantum memories for global quantum networking
Top: Hybrid QND-QR protocol, following37 with nesting level, n = 1 and segment length, L0. Entangled photon pairs are created by on-board sources (red stars) and sent to ground stations (I). After a QND detection heralds the arrival of the photons they are loaded to QMs (II). BSM is performed between the memories to extend entanglement between end stations (III). Bottom: New architecture where the QND and QMs are also located on-board an orbiting satellite.
