Satellite quantum communication

Definition:
Satellite quantum communication refers to the use of satellites to transmit quantum information, often via entangled photon pairs, between ground stations separated by long distances. This approach enables ultra-secure communication by circumventing the signal loss and decoherence that occur in fiber-based quantum links.

Scientific context:
In this setup, a satellite:

• Generates entangled photons onboard or on the ground,

• Sends one photon of each pair to each of two distant ground stations, or

• Acts as a trusted node that shares quantum keys using protocols like BB84 or E91.

Key advantages:

• Reduced photon loss in free space compared to optical fiber over long distances,

• Global coverage, especially important for intercontinental Quantum Key Distribution (QKD),

• Supports the development of a global quantum network and future quantum internet.

Challenges include:

• Precise alignment and timing synchronization between satellite and ground stations,

• Weather-dependent reliability for ground-based receivers,

• Limited operational windows during satellite overpasses.

Example in practice:

• Ongoing missions in Europe and other regions are working toward building satellite constellations for quantum-secure global communications.

Media:

Source: ICFO