The QEYSSat Mission: Demonstrating Global Quantum Key Distribution Using a Microsatellite

The QEYSSat Mission: Demonstrating Global Quantum Key Distribution Using a Microsatellite

QEYSSat (Quantum EncrYption and Science Satellite) is a proposed microsatellite mission concept under development for the Canadian Space Agency (CSA) that will demonstrate long-distance quantum key distribution (QKD) from space. Under the leadership of principal investigator Dr. Thomas Jennewein of the University of Waterloo’s Institute for Quantum Computing (IQC) and in partnership with the Institut National d’Optique (INO), the University of Toronto Space Flight Laboratory (UTIAS/SFL) and the Neptec Design Group, COM DEV has advanced the QEYSSat mission concept over the last two years through a series of technical studies funded initially by Defense Research and Development Canada (DRDC) and subsequently by the CSA. QKD is a highly secure method of creating an encryption key between two remote parties using the exchange of individual photons. Current terrestrial quantum key networks employ optical fiber links for the photon exchange. The most important attribute of keys generated and distributed in this manner is the security of the method. In theory, QKD is impervious to eavesdropping because under the laws of quantum mechanics the properties of an individual photon cannot be measured without impacting its state. Any eavesdropping can therefore be detected, allowing a quantitative measurement of the security of the generated key. The principal shortcoming of this method is that single-photon exchange processes are necessary for the implementation of a QKD network, which requires either line-of-sight between the network nodes or the use of low-loss optical fiber. This line-of-sight requirement restricts distances due to the curvature of the Earth, and optical fiber is limited to distances of about 200 km due to losses. There is no way to implement a “repeater” or amplifier in the link because this would impact the state of the photon and essentially defeat the inherent anti-eavesdropping characteristics of the technique. Using satellites as nodes in the QKD network would overcome this distance limitation and allow keys to be distributed over much larger distances. QEYSSat will demonstrate QKD from space, providing insight into single-photon link behavior and also serving as a platform for fundamental quantum physics experimentation. The proposed mission is currently baselined to use the AIM (Advanced Integrated Microsatellite) bus developed by COM DEV for M3MSat (Maritime Monitoring and Messaging Micro-Satellite). AIM is a responsive, flexible and cost-effective platform that meets or exceeds the CSA’s Multi-Mission Microsatellite Bus (MMMB) specification. The proposed QEYSSat spacecraft would carry a quantum payload designed to measure the polarization of individual photons. It would operate in conjunction with dedicated ground stations that will transmit the polarized photons. The payload is expected to have the capability to generate the quantum keys and manage their distribution between distant ground stations. This paper will describe the proposed QEYSSat mission concept and summarize the development work to date. A successful demonstration of QKD from space could pave the way for the future development of secure global quantum networks for users in both government and the private sector.