On 12 August 2026, parts of Europe will witness a total solar eclipse, a rare event that lasts only minutes. But scientists at ESA are not waiting for the Moon to reveal the Sun's hidden corona. They have built a pair of satellites that create artificial eclipses on demand, giving them hours of observation time instead of fleeting moments.
The corona, the Sun's outer atmosphere, is where space weather is born. It is here that the solar wind accelerates and coronal mass ejections originate, events that can disrupt satellites, power grids, and communications on Earth. Yet this region is normally invisible, its faint glow drowned out by the Sun's bright disc. Only during a total eclipse, when the Moon blocks the Sun, can the corona be seen with the naked eye.
A Mission That Mimics the Moon
ESA's Proba-3 mission, launched to solve this problem, consists of two satellites flying 150 meters apart. One spacecraft, the Occulter, acts as the Moon, blocking the Sun's light. The other, the Coronagraph, carries an instrument called ASPIICS to capture images of the corona. This setup allows scientists to observe the corona for hours at a time, not just the few minutes a natural eclipse provides.
Andrei Zhukov, principal investigator for ASPIICS at the Royal Observatory of Belgium, noted that Proba-3 recently completed its 62nd artificial eclipse. This particular image was taken about two weeks before the upcoming natural eclipse, a timing that is scientifically valuable because the Sun rotates halfway around its axis in that period.
Why Local People Care
For people in Greenland, Iceland, Spain, and Portugal, the August 12 eclipse is a spectacular event, turning day into twilight for over two minutes. But for scientists, it is a rare chance to study the corona from the ground, complementing the data Proba-3 gathers from space. The mission's artificial eclipses are not just a technical feat; they are a way to extend our understanding of the Sun's influence on our technology-dependent world.
The ability to create eclipses on demand means researchers no longer have to wait for rare natural events. Proba-3's continuous observations help fill gaps in our knowledge, particularly the region between the Sun's surface and the outer corona, which most coronagraphs cannot image.
As the natural eclipse approaches, the data from Proba-3's 62nd artificial eclipse will be compared with ground-based observations. This synergy between artificial and natural eclipses could unlock new insights into the corona's behavior, helping to predict space weather that affects us all.
