The 50 kg satellite itself consists of two main sections. The lower half of ESEO is a payload module, where the scientific instruments are housed, along with a micropropulsion system. The upper half houses instrumentation necessary for the satellite to function, such as batteries and an on-board computer. The satellite platform is arranged in different “trays” that are then stacked together. In detail, the payloads, platform subsystems, and ground stations developed by the students are:

TriTel – Hungarian Academy of Science, Budapest, Hungary
The ESEO-TRITEL payload is a scientific experiment to study the cosmic radiation environment experienced during ESEO’s orbit. The effects of solar activity will be studied, along with the special interaction between cosmic radiation and regions of Earth such as the Poles and the South Atlantic Anomaly.

Langmuir Probe – Budapest University of Technology and Economics, Hungary
The Langmuir Probe (LMP) is a scientific experiment whose main objective is to investigate the effect of solar activity on the Earth’s ionosphere. Besides analysing the normal characteristics of the plasma and obtaining more information about plasma anomalies, the payload will acquire data of geomagnetic disturbances induced by solar eruptions and Coronal Mass Ejections (CMEs), phenomena that are accompanied by ionospheric storms.
Power Distribution Unit and Protection Boards – Budapest University of Technology and Economics (BME), Hungary

The Power Distribution Unit (PDU), fundamental for the functioning of the satellite and its payload, consists of two identical motherboards – one main and one backup. The ESEO PDU will also serve as the first in-flight test platform of a novel design of digital LCL (Latching Current Limiter) protection circuitry, developed under ESA contract, and utilised in the boards designed by the BME university students team.
Digital Cameras –Tartu Observatory, University of Tartu, Estonia

The ESEO Digital Cameras are the satellite’s optical payload. They must be rock-solid reliable, able to endure the harsh environment of space, and take images of the Earth in the visible spectrum for scientific and public outreach purposes. This payload actually consists of two miniature cameras: a wide-angle camera (primary), and a telescopic camera (secondary).
HSTX – University of Wroclaw, Poland

The S-band communication subsystem payload (HSTX) will allow the ESEO satellite to transmit scientific data at a high data-rate. It comprises transmitter, a Radio Frequency (RF) power amplifier, and the patch antenna. The HSTX is able to transmit data to the ground station at a rate of 10MB per second.
AMSAT-UK Transceiver – University of Surrey, UK

The ESEO AMSAT-UK payload is a radio communication system available for students and amateur radio users around the world. It is able to perform digital signal processing to transmit the ESEO telemetry on radio-amateur frequencies.
De-Orbit Mechanism – University of Cranfield, UK

The Cranfield De-Orbit Mechanism (DOM) is a technology demonstration experiment. It is designed to deploy a drag sail at the end of the satellite mission that will allow the ESEO orbit to decay more rapidly, and the satellite to be safely disposed of via atmospheric burn-up on re-entry.
GPS Receiver – University of Bologna, Italy

This experiment is focused on the precise real-time GPS-based positioning of satellites in low Earth orbit (LEO), using a single frequency receiver and advanced estimation algorithms. It aims to verify the possibility of determining the positions of LEO satellites in real-time, in orbit, and with very high accuracy.
Attitude Determination Experiment – TU Delft, The Netherlands

The Attitude Determination Experiment (ADE) is a software capable of estimating the attitude (orientation) of the satellite by four different algorithms running in parallel, having as inputs the data provided by the satellite attitude sensors. The performance of the different algorithms will be tested in-orbit during the ESEO mission.

Control Centre and UHF Primary Ground Station – University of Bologna, Italy
The team at University of Bologna has set up the primary centre for the mission control of the ESEO satellite platform and two ground stations (located in Forlí, Italy), which will be part of the ESEO ground station network:
• The UHF Primary Ground Station will allow communication between Earth and the satellite (uplink) and, vice versa, receive the satellite’s data and telemetry back on Earth (downlink). It operates in the UHF amateur radio frequency band (430-440 MHz) using a Yagi antenna.
• A secondary ground station operating in the S-band (around 2.4 GHz) is downlink-only, and uses a 3-metre diameter parabolic antenna.

UHF Secondary Ground Station – University of Vigo, Spain
The University of Vigo provides a secondary ground station to be used for satellite operations in case of unavailability of the primary station based in Italy. A software called SatNet, developed along with researchers from the California Polytechnic State University, will enable remote operations of this ground station.

S-band Primary Ground Station – Polytechnic of Munich, Germany
The Munich ground station consists of a 3m mesh reflector antenna that is mounted on a former industrial robot placed on the roof of the university institute. In nominal operations, all scientific payload data generated from the satellite (e.g. images and measurements) are sent from the satellite towards this ground station.