Belgian Proba-3 Satellites Capture Rare Double Solar Eclipse
Belgian-built satellites have captured a unique double solar eclipse in space, a rare astronomical phenomenon that occurred hours before the Moon’s shadow swept across parts of Europe on 12 August 2026. The observation, made by the European Space Agency’s (ESA) Proba-3 satellite pair, provides valuable scientific data and showcases Belgium’s significant role in space technology.
The double eclipse occurred when the Moon crossed the field of view of the Proba-3 satellites’ ASPIICS coronagraph instrument while the mission was simultaneously creating its own artificial eclipse, according to VRT NWS. The event lasted 8 minutes and 40 seconds for Proba-3, significantly longer than the maximum duration of totality on the ground, which was 2 minutes and 18 seconds just off the coast of Iceland.
The Proba-3 Mission
Proba-3, launched in December 2024, consists of two satellites that fly in formation with extraordinary precision, maintaining their relative positions to within a few millimeters over a distance of 150 meters. One satellite carries an occulting disk that blocks the Sun, while the other carries the ASPIICS coronagraph telescope that observes the solar corona. Together, they function as a single giant coronagraph capable of creating artificial solar eclipses lasting up to five hours per orbit, as Forbes reported.
The mission has a significant Belgian component. The satellites were built and tested at Redwire Space in Kruibeke, the ASPIICS instrument was developed under the leadership of the Centre Spatial de Liège, scientific research is managed by the Royal Observatory of Belgium, and mission control is operated from the ESA centre in Redu in the Belgian Ardennes. Belgium contributed nearly €70 million of the total €200 million mission cost.
“It was a long and particularly complex effort,” said Stijn Ilsen, space engineer at Redwire Space who has worked on the project since 2008. “Never before had there been two satellites that could fly relative to each other with millimeter precision in space.”
A Rare Celestial Coincidence
The double eclipse was the 65th artificial eclipse created by Proba-3, but the first time the Moon joined in. Because Proba-3 was closer to the Moon than Earth was, the mission’s double eclipse lasted much longer than the maximum duration of totality on the ground, as ESA explained.
“It’s not really a video, but a sequence of individual photos,” Ilsen told VRT NWS. “It goes very fast. On Earth you see the moon move very slowly during a solar eclipse, but because the satellites fly through space at more than 30,000 kilometers per hour, the moon passes by super fast. That’s why you only have a limited number of images.”
During the nearly nine minutes of double eclipse, the ASPIICS coronagraph was essentially free from parasitic light normally produced by diffraction of solar disc light on the edge of the Occulter spacecraft. This allowed scientists to calibrate the optical performance of the coronagraph and observe the corona in the best possible conditions, according to Scientias.nl.
Scientific Significance
The simultaneous occurrence of an artificial eclipse in space and a natural eclipse on Earth allowed scientists to compare images and measurements from both, verifying the accuracy of Proba-3’s normal measurements. “Because you simultaneously have an artificial solar eclipse in space and a real one on Earth, you can compare the images and measurements of both,” Ilsen said. “This way you can check whether what we normally measure with Proba-3 is actually correct.”
The mission has already produced significant scientific results. Its first findings, published in March 2026 in the Astrophysical Journal Letters, revealed that parts of the slow solar wind travel three to four times faster than previous models predicted. “In the inner corona, a region very difficult to observe, we saw slow solar wind gusts moving three to four times faster than expected,” said Andrei Zhukov, principal investigator of ASPIICS at the Royal Observatory of Belgium, as reported by Belgium in Space.
The mission has not been without challenges. In February 2026, engineers temporarily lost contact with Proba-3 following a software anomaly. Contact was restored on 18 March 2026 after weeks of recovery efforts, as VRT NWS reported. “It’s fantastic news and a huge relief that contact has been restored,” said Damien Galano, Proba-3 Mission Director at ESA. “We worked tirelessly for a month to get the satellite operational again.”
What’s Next
A double eclipse like this is a once-in-a-lifetime event for Proba-3. Before the mission ends, it will experience two partial eclipses during the next two on-ground total eclipses on 2 August 2027 and 22 July 2028, when the Moon will pass through the ASPIICS field of view but will not cover the full solar disc.
Since the start of its nominal mission in July 2025, Proba-3/ASPIICS has collected more than 250 hours of data, equivalent to the duration of thousands of natural total solar eclipses observed from the ground. The mission continues to provide unprecedented views of the solar corona, helping scientists understand the fundamental processes that drive the solar wind and space weather that can affect Earth’s technological infrastructure.