QUBE

QUBE [Zentrum für Telematik]

QUBE is a German 3U CubeSat developed by Zentrum für Telematik with support from OHB System and German Aerospace Centre. The 3.5 kg satellite was launched on 16 August 2024 aboard the Falcon 9 rideshare mission. The spacecraft remains operational, with the latest mission update published on 11 April 2025. QUBE carries out quantum key distribution experiments using an optical downlink system.

The mission is intended to demonstrate secure quantum communication technologies in orbit. QUBE transmits strongly attenuated light pulses containing encoded quantum information, enabling the exchange of encryption keys through quantum key distribution techniques. A miniaturized quantum random number generator aboard the spacecraft produces random numerical sequences that define the quantum states of the transmitted light pulses. The mission serves as a technology demonstrator for future secure satellite-based communications systems.

The satellite was developed by Zentrum für Telematik in cooperation with OHB System and DLR. In addition to the quantum communication payload, the spacecraft includes UHF radio systems for telemetry, telecommand, and amateur radio operations. A specially developed UHF antenna system supports reliable uplink and downlink communications. The spacecraft also carries an onboard Raspberry Pi computer used for experimental payload operations and data handling.

QUBE is a 3U CubeSat with a launch mass of 3.5 kg. Communications operate in the 435–438 MHz amateur radio band. After completion of the primary scientific mission and LEOP activities, the spacecraft is planned to activate an onboard digipeater service accessible to the global amateur radio community. Telemetry, beacon transmissions, spacecraft health data, battery levels, temperatures, and experimental payload data are intended to be openly receivable by radio amateurs worldwide.

The satellite also supports educational activities at the University of Würzburg. Amateur radio communication experiments are integrated into student courses, including training for amateur radio licensing examinations and practical long-distance communications exercises. The mission aims to promote awareness of amateur radio operations and provide hands-on experience in low-power satellite communication, including challenges related to noise, weak signals, and Doppler shift compensation.