AcubeSAT’s work is separated into different subsystems. Each subsystem is responsible for just one part of the operation of the satellite, but the coordination of all subsystems is required in order to make it operational.
The Attitude and Determination Control System is responsible for determining the attitude of the satellite while it is in orbit using sensors and controlling the attitude to achieve the desired orientation using actuators. AcubeSAT uses several sensors and actuators to orientate itself in a way which enables the patch antenna to transmit the images from the scientific payload back to Earth.
Downlinking the scientific data in the form of images while also transmitting the status of the satellite and receiving commands from the ground is the main goal of the Communications Subsystem. To achieve this, the subsystem has two different antennas: one patch antenna, operating in S-band, in order to downlink the images and one deployable turnstile antenna, based on UPSat’s design, for Telemetry and Telecommand. To maximise the communications window, the ground station which is constructed within AUTh grounds is part of the SATNOGS network, enabling access to several other ground stations all over the globe.
The Electrical Power Subsystem is tasked with generating power and distributing it to every single subsystem of the satellite. The first step begins with harvesting power from the sun via the solar panels which are placed on the exterior sides of the satellite. The energy is then conditioned and stored in the batteries of the satellite, which have enough capacity to keep the satellite running at all times. The power is then delivered to the rest of the subsystems, with many protection circuits and failsafes ensuring that no components will be harmed in the process.
On-Board Computer is commonly referred to as the “brain” of the satellite. Using powerful and modern microcontrollers, the On-Board Computer is in charge of all actions taken by the satellite while maintaining constant communication with the rest of the subsystems using the CAN bus protocol. On-Board Computer members also write the code for the microcontrollers using embedded programming in C++ and furthermore assist the rest of the subsystems which are using a microcontroller with their coding expertise.
The biological experiment of our satellite will investigate the effects of low gravity and radiation on the behaviour of eukaryotic cells in orbit. Using a high-throughput microfluidics device and a miniaturized optic system, we aim to provide insights on the survivability and changes in human physiology in the space environment, applicable to astronauts on board the ISS, and to future space exploration missions.
Given the uniqueness of our scientific payload, the Structural team has to design and manufacture a pressurized vessel which will hold a pressure of about 1 atm. Inside the vessel, our scientific experiments will take place. The structural subsystem is also responsible for the design of our CubeSat’s frame and the configuration of the different components inside of it, while also performing analysis and simulations to ensure our satellite is going to survive launch conditions.
Integrating the different subsystems into a single system is the main task of our systems engineering team. In close collaboration with every single subsystem, the systems engineering team is responsible for the final system architecture, testing and verification procedures and the technical supervision of the project. The systems engineering team also operates different tools like OCDT, AcubeSAT’s ECSS database and the documentation management system, enabling our team’s members to work more efficiently.
The Thermal subsystem has one of the most challenging tasks inside the project: ensuring the temperature of the nanosatellite remains within acceptable limits for the survival of both our electronics and our payload. This is displayed in the so-called thermal analysis of the CubeSat, where the orbit environment is simulated and the team can see the temperature on the different parts of the satellite, enabling them to select the needed insulation materials to keep the temperature within an acceptable range.
The Trajectory subsystem is tasked with mission geometry, meaning it has to determine the optimal orbit for AcubeSAT taking into consideration the different mission/system requirements and the near-earth space environment. Trajectory runs several simulations to accurately determine the orbital lifetime of the satellite in order to ensure compliance with relevant treaties and to avoid the creation of space debris. Simulating the radiation environment of the orbit is also crucial for understanding the impact on our payload and the electronic components beforehand.