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Spacecraft charging
During enhanced solar activity, electrons trapped in the outer radiation belt of the Earth can be accelerated to high energies (>1 MeV, called killer electrons) by fast speed solar winds (originating from coronal holes) and interplanetary coronal mass ejections (CMEs).
At these energies, electrons can easily penetrate the skin of a spacecraft and the shielding layer of spacecraft components. Once inside the material (e.g. insulated polymers, glass, ...) the electrons slowly (hours to days) build up charges that can lead to high voltages and brake down the material through electrostatic discharge (ESD).
ESDs can create permanent changes in material properties, malfunctioning/disruption of critical devices and even the determination of a spacecraft mission.
A prototype space weather service
By coupling a charging code to observations and simulations of the electron radiation environment in the outer belt, risk estimates can be made for ESDs on board satellites moving in the charging environment. Simulations can be done for various combinations of simple shielding geometries, various materials and different electric grounding configurations.
The Space weather group at BIRA-IASB developed a prototype service in support of satellite operators, providing daily nowcasts and forecasts of charging risks at geostationary orbit. The service is available in ESA’s Space Weather Service Network for demonstration.
On May 10, 2024, a series of CMEs was launched by the Sun towards the Earth leading to a strong geomagnetic storm.
Acknowledgements
This work was carried out in the frame of ESA Space Safety Programme - Space Weather Service Network Development and Pre-Operation (part 1), supported under ESA contract number 4000134036/21/D/MRP.
