Nanobob: a CubeSat mission concept for quantum communication experiments in an uplink configuration

Abstract

We present a ground-to-space quantum key distribution (QKD) mission concept and the accompanying feasibility study for the development of the associated low earth orbit nanosatellite payload. The quantum information is carried by single photons with the binary codes represented by polarization states of the photons. Distribution of entangled photons between the ground and the satellite can be used to certify the quantum nature of the link: a guarantee that no eavesdropping can take place. By placing the entangled photon source on the ground, the space segments contains "only" the less complex detection system, enabling its implementation in a compact enclosure, compatible with the 12U CubeSat standard (∼12 dm 3). This reduces the overall cost of the project, making it an ideal choice as a pathfinder for future European quantum communication satellite missions. The space segment is also more versatile than one that contains the source since it is compatible with a multiple of QKD protocols (not restricted to entangled photon schemes) and can be used in quantum physics experiments, such as the investigation of entanglement decoherence. Other possible experiments include atmospheric transmission/turbulence characterization, dark area mapping, fine pointing and tracking, and accurate clock synchronization; all crucial for future global scale quantum communication efforts.

Satellite-based links for quantum key distribution: beam effects and weather dependence

“…Many recent proposals foresee the use of nano-satellites (e.g. CubeSats [58][59][60]) for QKD implementation [9,[61][62][63][64]. The possibility to deploy many of such satellites in a single mission, to share the vector with other payloads and the modular nature lowers considerably the launch and building cost of these devices.…”

“…The possibility to deploy many of such satellites in a single mission, to share the vector with other payloads and the modular nature lowers considerably the launch and building cost of these devices. They are usually loaded with smaller optics, of diameter 10 cm, even if larger apertures can be achieved with the use of deployable optics or bigger CubeSats (like the 12-Units satellite proposed in [63]). When used as transmitter, in the down-link configuration, the smaller aperture creates beams with much higher intrinsic divergence than the case studied in section 3.…”

From Connectivity to Advanced Internet Services: A Comprehensive Review of Small Satellites Communications and Networks

“…Interesting research is ongoing on the use of quantum cryptography. Some missions have been designed and developed, using nanosatellites and CubeSats, which show the feasibility of ground-to-space quantum key distribution (QKD) [75][76][77][78]. QKD uses individual light quanta in quantum superposition states to guarantee unconditional communication security between distant parties.…”

Q3Sat: quantum communications uplink to a 3U CubeSat—feasibility & design

“…a combination of a 50:50 beam splitter (BS), two PBSs, a HWP and four detectors, such as proposed for the 12U CubeSat of Ref. [16]) or an extremely fast active one (e.g. rapid Pockels cells).…”

“…Previous studies such as Refs. [12][13][14][15][16] have shown that space-based Q.Com is in principle feasible (also with small satellites) and culminated in two successful Q.Com satellites as well as other quantum experiments in space [17]. Recent efforts have evaluated the feasibility of downlinks [18] while others have attempted to solve the technological challenges identified by space-certifying detectors and sources of entanglement [19].…”