Blackout in Spain, the return of light seen by satellites

The gradual restoration of electricity in Spain and Portugal during the night of the blackouts between April 28 and 29 was documented by NASA's Suomi-NPP, Noaa-20 and Noaa-21 satellites , and thanks to the European Space Agency's scientific infrastructure, it could become a case study for monitoring light pollution and its impact on human health. The ESA reports this on its website.

The three satellites , which orbit the Earth from pole to pole, passed over Spain and Portugal six times between sunset on April 28 and sunrise on the 29th. Thanks to the cloudless sky, each passage provided a snapshot of the evolution of the situation on the electricity grid , to the point of composing the entire chronology and cartography of the blackout . "By superimposing the six satellite passes and applying NASA's night algorithms, we can identify large green spots that appear suddenly and gradually disappear," notes Alejandro Sánchez de Miguel, a researcher at the Institute of Astrophysics of Andalusia and head of several ESA-supported initiatives to monitor light pollution from space. "The green spots indicate the absence of light , while the white ones indicate areas with stable electricity supply . This distribution is consistent with the reports of electricity companies and with the gradual return to normality," adds the expert.

The Spanish blackout shows how space-based monitoring tools can help assess the resilience of infrastructure , prioritise repairs and facilitate emergency responses , but not only that. ESA coordinates and supports a scientific infrastructure that could turn power outages into case studies for investigating day-night rhythm disruptions in living organisms, including humans . For example, ESA contributes to the Night Watch project, a European multispectral mission studying night-time light emissions: cases like the Iberian blackout could help establish thresholds for future monitoring systems.