Nowadays, data breaches and cyberattacks are becoming increasingly sophisticated, raising the need for unbreakable encryption methods. One of the most promising tools in secure communication is Quantum Key Distribution. This method leverages the laws of quantum mechanics to generate and share encryption keys that are theoretically immune to intrusion. The ground-based system range is limited, but there is a way to overcome this. Researchers and companies turn their attention to satellite-based Quantum Key Distribution, enabling secure communication on a truly global scale.

Why satellites? Overcoming Earth-based limitations

On the Earth, the quantum signals in optical fibres or in the atmosphere cannot be reliably transmitted over long distances (typical ranges reaching a maximum of 100-200 kilometres), making it challenging to implement QKD. These limitations led researchers and space agencies to explore the use of satellites to overcome those terrestrial constraints. Satellite-based QKD offers the possibility of global quantum communication by enabling secure key exchanges between ground stations separated by thousands of kilometres, far beyond the reach of fibre-optic networks. In the vacuum of space, photons can travel vast distances with acceptable losses.

Technology and challenges in Orbit

The process of implementing QKD in satellite missions involves using entangled photons or single photon sources on-board the satellite. In the most common implementations a quantum key signal is generated on-board of the satellite and transmitted to optical receivers on the ground. Some critical factors that can influence the quality and the success of the quantum link are timing and pointing precision, atmospheric disturbances or satellite tracking.

There are, however, some ways to address these challenges, such as the advances in optics, adaptive systems, pushing the boundaries of what is technically possible.

Milestones in Quantum Space Communications

In 2016, China launched the Micius satellite, the world’s first QKD satellite. Micius successfully demonstrated QKD between satellite and ground stations and even between stations located on different continents. This achievement proved the feasibility of using Low Earth Orbit satellites for secure quantum communication on a global scale.

Since then, numerous countries and organizations, such as the European Space Agency (ESA), the United States, and Japan, have initiated similar satellite QKD programs, recognizing the strategic importance of quantum-secure networks.

Significant steps in this field are taken by the European Space Agency to position Europe as a leader in space-based Quantum Key Distribution.

ScyLight program – ESA supports research and missions that advance optical and quantum communication technologies.

QUARTZ – a platform aimed to deliver QKD services using geostationary satellites, for use in geographically-dispersed networks.

EAGLE-1 satellite mission – a key initiative developed in partnership with the European Commission and set to demonstrate QKD between space and ground stations across Europe.

EuroQCI – an initiative which seeks to build a continent-wide quantum communication infrastructure combining both terrestrial and satellite networks.

Heading toward a Global Quantum Internet

Looking ahead, the integration of Quantum Key Distribution into satellite missions will play a pivotal role in establishing a global quantum information network. Currently, companies are making efforts to standardize protocols, miniaturize payloads, and develop quantum-compatible satellite constellations. As quantum technology matures, satellite-based QKD could become a cornerstone of a future secure communications infrastructure, protecting sensitive information from any threats posed by quantum computing or cyber warfare.

Living in a new era of cybersecurity

Exploring the unique properties of quantum physics and extending the reach of secure communications beyond the Earth-based infrastructure, satellite-based QKD offers a future where global data privacy and integrity are fundamentally protected, representing a transformative shift in the approach to cybersecurity.

QKD vs. Post-Quantum Cryptography. What’s the difference?

Quantum Key Distribution offers information-theoretic security, but its deployment, especially via satellite remains pretty complex and, sometimes, costly.

In contrast, Post-Quantum Cryptography (PQC) provides quantum-resistant encryption algorithms designed to run on today’s classical networks and hardware. PQC is easier to integrate into existing infrastructure and is currently being

Post-Quantum-Cryptography offers a more accessible short- to medium-term solution for quantum-resilient security, but it does not provide the same level of theoretical security as QKD.

However, QKD and PQC can form a complementary security landscape: PQC offering immediate deployability, while QKD providing the highest level of long-term protection for sensitive communications.

AROBS Polska holds a pioneering position as the first Polish company to collaborate with scientific partners to develop satellite quantum key distribution. We specialize in harnessing the power of FPGA to create the quantum communication solution for the needs of every project. Here, you can read more about our solutions and projects in the QKD field.