CaltechAUTHORS
Published December 25, 2025 | Version Published
Journal Article Open

Satellites promise global-scale quantum networks

Creators

  • 1. ROR icon Academia Sinica
  • 2. ROR icon University of Calgary
  • 3. ROR icon Virginia Tech
  • 4. ROR icon Harvard University
  • 5. ROR icon California Institute of Technology
  • 6. ROR icon Boeing (United States)
  • 7. ROR icon University of Strathclyde
  • 8. ROR icon Indian Institute of Technology Kharagpur
  • 9. ROR icon Humboldt-Universität zu Berlin

Abstract

Academia, governments, and industry around the world are on a quest to build long-distance quantum communication networks for a future quantum internet. Using air and fiber channels, quantum communication quickly faced the daunting challenge of exponential photon loss with distance. Quantum repeaters were invented to solve the loss problem by probabilistically establishing entanglement over short distances and using quantum memories to synchronize the teleportation of such entanglement to long distances. However, due to imperfections and complexities of quantum memories, ground-based proof-of-concept repeater demonstrations have yet been restricted to metropolitan-scale distances. In contrast, direct photon transmission from satellites through empty space faces almost no exponential absorption loss and only quadratic beam divergence loss. A single satellite successfully distributed entanglement over more than 1,200 km. It is becoming increasingly clear that quantum communication over large intercontinental distances (e.g., 4,000–20,000 km) will likely employ a satellite-based architecture. This could involve quantum memories and repeater protocols in satellites, or memory-less satellite-chains through which photons are simply reflected, or some combination thereof. Rapid advancements in the space launch and classical satellite communications industry provide a strong tailwind for satellite quantum communication, promising economical and easier deployment of quantum communication satellites.

Copyright and License

© 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

Acknowledgement

Authors acknowledges Aephraim M. Steinberg for fruitful discussions. M.M. and J.R.L. acknowledge support from Boeing. J.S.S. and D.K.L.O would like to acknowledge the support of the EPSRC Quantum Technology Hub in Quantum Communications (EP/T001011/1). This work was supported by the EPSRC International Network in Space Quantum Technologies INSQT (EP/W027011/1). D.K.L.O. is supported by the EPSRC Integrated Quantum Networks Hub (EP/Z533208/1). M.K. and M.G. acknowledge the support from the DLR through funds provided by the Federal Ministry for Economic Affairs and Climate Action (Bundesministerium für Wirtschaft und Klimaschutz, BMWK) under Grants No. 50WM1958, 50WM2055 and 50WM2347. M.G. further acknowledges funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 894590 and Einstein Foundation Berlin for support. Y.C.C. and H.H.J. acknowledge support from the National Science and Technology Council (NSTC), Taiwan, under the Grants Nos. 112-2112-M-001-079-MY3 and NSTC-112-2119-M-001-007, from Academia Sinica under Grant AS-CDA-113-M04 and are also grateful for support from TG 1.2 of NCTS at NTU. C.S. acknowledges the Natural Sciences and Engineering Research Council of Canada for its Alliance Quantum Consortia grants ARAQNE and QUINT, and the National Research Council for its High-Throughput Secure Networks challenge program.

Data Availability

No data were generated or analyzed for the present article. All results and graphs were reproduced from previously published research articles, which were duly cited.

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Additional details

Related works

Is new version of
Discussion Paper: arXiv:2505.06693 (arXiv)

Funding

Boeing (United States)
Engineering and Physical Sciences Research Council
EP/T001011/1
Engineering and Physical Sciences Research Council
EP/W027011/1
Engineering and Physical Sciences Research Council
EP/Z533208/1
Federal Ministry for Economic Affairs and Climate Action
50WM1958
Federal Ministry for Economic Affairs and Climate Action
50WM2055
Federal Ministry for Economic Affairs and Climate Action
50WM2347
European Union
894590
Einstein Foundation
National Science and Technology Council
112-2112-M-001-079-MY3
National Science and Technology Council
NSTC-112-2119-M-001-007
Academia Sinica
AS-CDA-113-M04
National Taiwan University
TG 1.2
Natural Sciences and Engineering Research Council
National Research Council Canada

Dates

Submitted
2025-05-13
Accepted
2025-11-04
Available
2025-12-16
Published online

Caltech Custom Metadata

Caltech groups
Division of Physics, Mathematics and Astronomy (PMA)
Publication Status
Published