Technical components of YPSat

Structural Subsystem

The body of YPSat is an aluminium tower-like structure made from four side panels and five shelves stacked inside the structure to contain its various subsystems. All these parts were first modelled, then manufactured and assembled using precision pins and bolted connections. This structure will allow the mounting of YPSat onto an aluminium plate which is bolted on Ariane 6 payload platform.  

The structure of YPSat plays a significant role in withstanding the forces during the launch that might disturb the operation of its equipment, or even damage the payload itself. Vibration tests were executed to test the structural integrity of YPSat. During these tests, YPSat underwent a rigorous examination to simulate the intense vibrations it will experience during launch. This test simulates the static and dynamic loads expected during the launch of Ariane 6 by subjecting YPSat to the flight qualification level loads in the X-, Y- and Z-axes. The outcome of this test – in addition to functional check results - provided an understanding of the behaviour of both the structure and the electrical harnessing of the YPSat, guaranteeing their readiness for launch.

Wake-Up Subsystem

The Wake-Up Subsystem (WUS) is essential to initiate the power-up sequence of YPSat upon detecting Ariane 6's lift-off. Prior to the launch, YPSat will be held in a state of hibernation to preserve power following its last battery charging before encapsulation and the launch. The WUS operates autonomously, featuring an accelerometer and a barometric pressure and temperature sensors, to detect the launch event by monitoring the movements of the payload.

The launch is identified after detection of significant acceleration, followed by assessments of the barometric pressure to confirm the launch event. In parallel, a secondary independent circuit serves as a backup for the wake-up. This circuit monitors the deployment signal that will be sent out by Ariane 6 when in orbit. This backup wake-up signal is passed to the On-Board-Computer and ensures a late wake-up in case of non-conformance in the WUS. It is also used when the self-detection of the launch was successful: the mission timeline is resynced with the time of this signal to get more precision on the timings.  Once the launch is detected, the Electrical Power System is activated to initiate start-up of YPSat.

Power subsystem

YPSat is powered only by a battery and not by solar arrays, unlike most satellites, due to its limited operational lifespan of about three hours. YPSat therefore relies upon power supply by a Lithium-ion battery (84Wh) alongside a Commercial Off-The-Shelf (COTS) power subsystem designed for power regulation, control, and distribution throughout the payload.

On-Board Computer and data handling

The On-Board Computer (OBC) hardware is the central processing unit of YPSat, interconnecting all subsystems and payload components. The OBC hardware is encased within an aluminium box to shield from ionising radiation and to ensure electromagnetic compatibility. Its software relies on a real-time operating system to facilitate memory management, telemetry functions, and task scheduling. Additionally, the software incorporates a watchdog timer to synchronise the coordination among the various subsystems and payloads throughout the mission phases, including power-up, recording, data transfer, and downlink transmission.

To guarantee that the electronics do no emit nor receive electromagnetic radiation beyond the specified restrictions, the electromagnetic compatibility (EMC) test was executed in early 2024. The EMC test consists of two evaluations: the Emission Test and the Immunity Test. During the emission test, the YPSat's electromagnetic radiation was measured. Positioned within an anechoic chamber, all emitted signals were measured to ensure compliance with specified restrictions set by Ariane 6, mitigating the risk of any interference with the launcher operations.

Conversely, the immunity test assessed the YPSat's resilience against electromagnetic interference emanating from external sources. By subjecting the YPSat to varied electromagnetic fields across different frequencies and strengths, this test verified that the electronic equipment within the spacecraft function correctly and other equipment around YPSat (including the launcher) are not disturbed or even disrupted in their operations.

Thermal Subsystem

The temperature of YPSat is controlled by a passive thermal control system. This entails Multi-Layer Isolation (MLI) around the YPSat which balances the radiated and absorbed heat and gives a shiny look to the YPSat. This MLI consists of 9 layers, including copper, aluminium, Nomex and aluminised Mylar layers. A critical component which must stay well preserved during flight is the On-Board Computer (OBC). This component has an additional form of thermal protection, Docosane Phase Change Material (PCM). As the satellite’s internal energy increases, this substance melts to absorb any excess thermal energy, allowing the OBC to adequately operate.

Thermal tests, including Thermal Vacuum Chamber (TVAC) test and backout tests, were performed to assure the functioning of the YPSat in space environment, where the thermal system plays a critical role.

Telecommunications

The telecommunication subsystem facilitates the downlink, transmitting the signals and data from our YPSat in space to Earth via the ground stations. This communication is enabled by an S-Band transmitter and a patch antenna. The duration of the downlink communication varies based on the location of the ground station, either ESA ESEC (European Space Security and Education Centre) (Belgium) or ESA ESOC (European Space Operations Centre) (Germany). YPSAT's visibility above the horizon will last around 800 seconds. Within this timeframe, there is a window of approximately 430 seconds during which a downlink signal for transmitting data can be established, accounting for the roll of Ariane 6.  

Scanway

In addition to our subsystem, the YPSat will be carrying some of our partners’ payloads. Scanway plays a crucial role in the YPSat project by delivering their high-quality cameras to our team. These cameras will capture the main objective of the YPSat: observing the fairing separation and the deployment of the CubeSats from Ariane 6.

AMSAT EA

The GENESIS-A module is a payload of our partner AMSAT EA. The module includes an FM repeater, a miniature camera that transmits captured images as an audio signal, and a deployable antenna. The antenna is a short dipole with a peak gain of 2 dBi, designed to transmit with very low power to avoid interference with the Ariane 6 signal. The module’s design allows for global reception by radio amateurs and includes technical support from Hydra Space.

OSCAR-QUBE+

OSCAR-QUBE+ is a device designed by students from the University of Hasselt Belgium and is set to be integrated onto YPSat. Their diamond-based quantum magnetometer will measure the Earth’s magnetic field along the Ariane 6 trajectory. OSCAR-QUBE’s mission is to measure the magnetic field in low Earth orbit (LEO) and evaluate and study contributing sources originating from i.e. Earth’s geodynamics, lithospheric movements, or mineral resource deposits. The characteristics of their device together with large geographical coverage of the ISS will allow the team to acquire a high resolution map of the magnetic field around the globe.

EnduroSat

Our last partner, EnduroSat, supplied the essential COTS (commercial off-the-shelf) components to complete the YPSat system design. This involved the delivery of the needed on-board computer, battery pack, transmitter and S-band antenna. These components provide the core functionality of the YPSat, such as data processing, energy storage, communication and telemetry. EnduroSat also provided technical support and documentation for the integration and testing of the components with the rest of the satellite subsystems.

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