The HSTX team working with Professor Pawel Kabacik is composed of four MSc students, one BSc student, six supervising professors, and a research assistant. They are providing an S-Band patch antenna to transmit data from all the ESEO experiments to the ground station.
Enabling a high data rate downlink for the satellite’s scientific data
The S-band communication subsystem payload (HSTX) comprises a high data rate transmitter, an RF power amplifier, and an antenna. The HSTX is able to transmit data to the ground station in the 2200-2290 MHz frequency range with 10 Mbps data rates. The signal on the downlink can be modulated in five ways (BPSK, QPSK, OQPSK, 4D-TCM-8PSK - 2.0 and 2.5). The downlink binary stream is CCSDS protocol compliant. It uses concatenated coding, incorporates the ASM marker, and operates virtual channels for the telemetry transfer frame protocol.
The HSXT is active in two ESEO operation modes: nominal and safe. The RF signal power is 2 Watts when using ground station with a 3-metre dish antenna. The unit’s total power consumption is under 10 Watts. The onboard antenna makes use of ground breaking composite antenna technology. The total mass of the system is under 1 kg.
An important feature of the HSTX transmitter is the implementation of functions normally allocated to onboard computers. In the case of ESEO, the S-band communications system acquires all data produced by the payloads and stores them in an internal memory until the S-band ground station is visible.
Due to the use of the high rate communication link, all the saved data saved can be transmitted to the ground station in a relatively short time. The system starts operating when the satellite is a few degrees above the horizon.
The members of the HSTX team started working together on various projects (e.g. SSETI Express) in 2001. Their participation in these projects and their involvement with ESEO has been extremely valuable to them.