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 low earth orbit CubeSat 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.

Spooky action at a global distance: analysis of space-based entanglement distribution for the quantum internet

“…Therefore, it appears that a satellite-based scheme will remain the preferred option over ground-based repeater schemes into the near term, especially with the improving miniaturization and increasing fidelity of entanglement sources 65,90 and the decreasing cost and miniaturization of satellites 51,53,54 . Our analysis of a global, satellite-based quantum internet opens the door to plenty of further study.…”

“…Satellites have been recognized as one of the best methods for achieving global-scale quantum communication with current or near-term resources 23,[50][51][52][53][54] . Using satellites is advantageous due to the fact that the majority of the optical path traversed by an entangled photon pair is in free space, resulting in lower loss compared to ground-based entanglement distribution over atmospheric or fiber-optic links.…”

“…Several proposals for satellite-based quantum networks have been made that use satellite-to-ground transmission, ground-tosatellite transmission, or both 50,53,54,[61][62][63][64][65][66][67][68][69] . Recent experiments 65,[70][71][72][73][74][75][76] (see also ref.…”

Advances in space quantum communications

“…There are approximately 65 6U missions under development. Since CubeSats are not restricted to Earth orbits, some missions choose the relatively bulky 12U form factor to be able to accommodate the largest possible telescope aperture on a CubeSat [203]. A review on all current approaches of satellite QKD enabling initiatives has been summarised by Bedington et al [206].…”

Increasing the Link‐distance of Free‐space Quantum Coherent Communication with Large Area Detectors

“…Transmission of signal through a free‐space channel creates signal loss due to beam divergences. One way to decrease the signal divergence is to use a large aperture telescope at the transmitter as per the following relation with the divergence angle Θ = 1.22 λ / D , where λ is the wavelength of the signal and D is the diameter of the transmitter telescope [20]. For transmission over short distances, the beam diameter can be maintained below a typical receiver telescope diameter (say, 40 cm diameter) by using a suitably large transmitter aperture.…”