Night time images from NASA's Suomi-NPP, NOAA-20 and NOAA-21 satellites captured the extent of the outage and monitored the gradual recovery of power from space.

These records show areas with prolonged power outages and with power supply restored overnight, the Europa Press agency reported.

The three satellites, orbiting the Earth from pole to pole, made six passes over Spain and Portugal between dusk and dawn on April 29.

Each pass provided an instant record of the evolving situation on the power grid.

The six images illustrate the chronology and mapping of the blackout, from the first orbits at dusk until the almost total recovery around 05:00 (04:00 in Lisbon).

"By overlaying the six satellite passes and applying NASA's night time algorithms, we can identify large green spots that appear suddenly and gradually disappear," explained Alejandro Sánchez de Miguel, a researcher at the Andalusian Institute of Astrophysics (IAA-CSIC) and leader of several initiatives supported by the European Space Agency (ESA) that monitor light pollution from space, in a statement.

Credits: Supplied Image; Author: NOAA/NASA (VIIRS/DNB), processed with Black Marble;

"The green dots indicate power outages, while the white dots show areas with stable power. This distribution is consistent with reports from energy companies and the gradual return to normality," added Sánchez de Miguel.

According to ESA, this widespread outage highlights how space-based monitoring tools can help assess infrastructure resilience, prioritize repairs, and facilitate emergency responses.

The European Network of Transmission System Managers for Electricity (ENTSO-E) announced the creation of a committee to investigate the causes of this blackout, which it described as “exceptional and serious”, and which left Portugal and Spain in the dark.

This panel of experts will have to prepare a factual report that will form the basis of the final report by the deadline of October 28 this year. The final report on the investigation into the incident must be published by September 30, 2026 at the latest.