Table 2 A summary of satellite QKD enabling initiatives

QUESS²⁰

LEO-to-ground trusted-node satellite QKD, uplink quantum teleportation and double-downlink entanglement distribution.

Micius 631 kg satellite.

Entanglement distribution of 1203 km⁴⁷, teleportation up to 1400 km⁴³ and BB84 QKD up to 1200 km with QBER ~1% and sifted key 14 kbps.⁴²

Toyoshima et al.¹²¹

LEO-to-ground polarization measurement.

OICETS 570 kg satellite.

Polarization preserved within system rms error of 28 mrad.

Takenaka et al.^{90, 122}

LEO-to ground polarization measurements from a small optical transponder (SOTA).

SOCRATES 48 kg satellite.

Effectively no depolarization was observed (100% Degree-of-polarization) and QBER of < 5%.

Günthner et al.¹⁰³

GEO-to-ground test of quantum state used in coherent communication.

Alphasat I-XL 6649 kg satellite.

Quantum-limited states arrive on the ground after transmission from satellite.

Vallone et al.⁴⁶

Test of polarization state for weak coherent pulses using retro-reflectors on LEO satellites.

Jason-2 510 kg, Larets 21 kg and Starlette/Stella 48 kg satellites.

Average QBER of 6.5% achieved.

Yin et al.¹²²

Test of polarization state for weak coherent pulses using retro-reflectors in a LEO satellite.

CHAMP 500 kg satellite.

Signal to noise ratio of 16:1 observed for polarization measurements.

Dequal et al.¹²⁴

Test of weak coherent pulse transmission from retro-reflectors on a MEO satellite.

LAGEOS-2 411 kg satellite.

Peak signal-to-noise ratio of 1.5 with 3 counts per second.

Tang et al.¹⁹

In-orbit observation of polarization correlations from a photon-pair source on a nano-satellite.

Galassia 2 kg 2U CubeSat.

97% contrast in polarization correlation measurements. Pathfinder for SpooQySats (below).

Nauerth et al.¹²⁵

QKD between the ground and a aircraft moving at similar angular velocities to a LEO satellite.

Dornier 228 utility aircraft.

Sifted key rate of 145 bps, QBER of 4.8% from range of 20 km at angular speed of 4mrad per second.

Bourgoin et al.¹⁸

QKD with a moving receiver similar to the angular speed of satellite at 600 km altitude.

Pick-up truck.

Key rate of 40 bps with QBER of 6.5 to 8% with receiver at a range of 650 m moving at angular speed of 13 mrad per second.

Wang et al.¹²⁶

Verification of pointing, acquisition and tracking.

Hot-air balloon.

Key rate of 48 bps and QBER of ~4% over a range of 96 km.

SpooQySats¹²⁷

Demonstrate polarization-entangled photon-pair sources in space.

3U CubeSats.

Funded mission. Launches planned from 2018.

QEYSSat⁴³

Trusted-node receiver for uplink QKD.

Microsatellite.

Funded mission.

CAPSat⁹⁴

Laser annealing of radiation-damaged APDs.

3U CubeSat.

Funded mission.

NanoBob¹²⁸

Trusted-node receiver for uplink QKD.

CubeSat.

Proposal.

SpaceQUEST (2008)⁴¹

Double LEO-to-ground downlinks QKD using polarization-entangled photon-pairs.

International Space Station.

Proposal (since updated as a mission exclusively investigating decoherence due to gravity¹¹¹).

Scheidl et al.⁸⁶

Entanglement-based QKD and Bell tests, ground-to-LEO.

International Space Station.

Proposal.

NanoQEY¹⁰⁹

QKD and Bell tests ground-to-LEO with a trusted-node satellite.

Based on NEMO nanosatellite bus, 16 kg.

Proposal.

Zeitler et al.⁸⁵

Superdense teleportation, LEO-to-ground.

International Space Station.

Proposal.

QuCHAP-IDQuantique

Establish QKD networks based on high altitude platforms.

High-altitude platform.

Proposal.

CQuCom⁵³

LEO-to-ground QKD downlinks.

6U CubeSat.

Proposal.