One of the most visible effects of space weather on Earth is the Aurora Borealis. Monitoring of the Aurora is an essential and central nowcasting and forecasting element since it enables indirectly the observation of the Solar Wind variations and the impact of Coronal Mass Ejections (CME), which may cause geo-magnetic storms and sub-storms when hitting the Earth.
Aurora phenomenon is a direct manifestation of physical processes occurring when the magnetosphere responds to the solar wind and CMEs plasma streams that strongly alter the interplanetary and geomagnetic field of the Earth. Auroral emissions (optical, far-UV and X-ray) on the day and night-side and their time sequence contain information about the characteristics of the particles flow and about physical and chemical processes occurring locally and in the upper atmosphere, namely the ionosphere. Observations at the boundary of the auroral oval may be used as input to the modelling of geo-magnetic storm conditions, and finally the posteriori reconstruction furthering the understanding of space weather events. Additional instrumentation dedicated to in-situ measurements in the polar regions may be used to determine the underlying conditions such as plasma drift velocities, magnetic and transpolar magnetospheric electric fields, field aligned currents as well as the particle precipitation densities.
Aurora research shall fill this specific gap and improve services dependent on the modelling of the Earth’s magnetic and electric field and currents (services that are used for example, for aviation, transport in high latitude regions, telecommunication, search and rescue, and power grid operation). The Aurora satellites shall constantly monitor the Auroral oval and the location of on-going geomagnetic storms and sub-storms and provide information to the locally affected users support nowcasting and forecasting of Aurora visibility for the tourism sector. The socio-economic impact of solar storms on human-made space and ground assets may reach up to €15 billion for a single major solar event.
The foreseen implementation of the mission, in Space Safety Programme Period 2, includes a demonstration mission (Aurora-D) with a single satellite focused on the Auroral oval imaging, followed by a full constellation mission (Aurora-C) of four to six SmallSats in a later period. The full constellation will enable continuous (24/7) monitoring of the Auroral oval from an elliptical orbit with an apogee of at least 2500 km.
The core instrumentation of Aurora is a low resource Wide Field of View Auroral Imager (WFAI) consisting of two modular assemblies, the Auroral Optical Spectral Imager (AOSI) and the Auroral UV Imager (AUI). The assemblies are currently under development and will allow multi-spectral imaging, thereby enhancing the reconstruction of the involved processes and the location of their origin. Additionally, as a goal, a magnetometer, plasma monitor and/or neutral atom particle spectrometer shall be considered in form of an in-situ instruments suite. A radiation monitor is also considered as required, preferably as platform equipment.
Aurora-C is the first auroral imaging mission for operational applications. The SmallSat constellation will make progressively use of innovative and highly miniaturised space weather instrumentation, and be based on a robust, reliable, agile and versatile small satellite platform likely with obit rising capability. In order to improve the data latency the use of an inter-satellite or in-space communication link may be considered for Aurora-C. The orbital constellation, satellite configuration (platform and instrumentation), ground segment, operation and launch scenario (including micro-launchers) of Aurora-D and Aurora-C are subject to optimisation conducted in the frame of the Auroral Oval Monitoring re-orientation Phase A
study that is part of S2P Period 1. For both mission elements, based on the assessment made during the Space Weather SmallSat (SWS) Phase A/B1 study, the estimated CaC is 50 M€ each. The replenishment of the constellation is potentially subject to commercialisation.