The Proba-3 mission has succeeded in an space engineering company never attempted before: it has obtained an artificial solar eclipse, an event of great scientific interest.
In March 2025, the European Space Agency (ESA) marked a revolutionary stage in the history of space engineering with the probable mission, succeeding in a company never attempted before: two space vehicles, the Coronagraph and the Occulter, flew into formation just 150 meters away from each other, keeping a millimeter precision for several hours, and everything without the direct control. And this It made it possible to obtain an artificial eclipse of the sun of great scientific interest. Only now, however, have been disclosed The first images.
The artificial solar eclipse. Once aligned, the two satellites give life to an unprecedented operation: they create artificial solar eclipses in space. The Occulter satellite carries a 1.4 -meter wide disk on board which, aligning with the sun, obscures its bright disc for the Coronagraph, projecting a shadow on it of just 8 centimeters. At that instant, the optical instrument of the Aspiics (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun), mounted on the Coronagraph, can observe the solar crown with a detail never reached before, without the solar glow that normally prevents its vision.
Developed by a consortium led by the Center Spatial de Liège in Belgium, ASPIICS has an opening of only 5 cm, but thanks to the innovative dual configuration of the satellites manages to obtain images comparable to those of a total natural eclipse. With a remarkable advantage: While the natural eclipses occur only once a year and last a few minutes, probable-3 is able to generate an eclipse every 19.6 hours and keep it up to six hours.
The secrets of the sun is revealed. The observation of the solar crown is essential to understand phenomena such as the sun wind and the expulsions of coronal mass (CME), explosions of particles that the sun emits almost daily and which, in periods of maximum activity, may have significant effects on earth. For example, as when in May 2024 a powerful CME compromised communications, GPS systems and electrical networks in different parts of the world. Probi-3 Aspiics manages to observe the crown near the sun surface, thanks to a drastic reduction of dispersed light.
An arsenal of tools. To understand how the sun works, in addition to ASPIICS, Proba-3 is equipped with two other scientific tools:
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Dara (Digital Absolute Radiometer) Measure total sunrise, or the amount of energy emitted by the sun at every moment.
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3dees (3D Energetic Electron Spectrometer) detects electrons in the terrestrial radiation bands, measuring their directions and energy levels.
Aspiics images are tried by the Scientific Operations Center (SOC) hosted at the Belgium Royal Observatory, where the team led by Andrei Zhukov, aspiration of Aspiics, elaborates the observations and sends the operating commands to the coronographer. “Each image is made up of three different exhibitions, combined to obtain a complete vision of the crown,” explains Zhukov. «The fact that these images are comparable to those of natural eclipses, but much more frequent and prolonged, represents a huge leap ahead for solar astrophysics».
Towards complete autonomy. The Flight Control Team currently supervises the flight in training, but the mission aims at complete operational autonomy, also eliminating the need for monitoring from the ground. “Our only task is now reaching full autonomy with respect to routine monitoring from the ground,” said Damien Galano, head of the mission.
In collaboration with the Belgian University Ku Leuven, ESA is using the Coconut software, integrated in the virtual spatial meteorological modeling center (VSWMC), for simulate and compare the real observations of the crown. “Proba-3 is the only tool that can observe the crown in such a clear way, which so far was possible only during natural eclipses,” says Jorge Amaya, ESA coordinator for space modeling. The simulations, combined with other physical models, help to better understand the phenomena that connect sun and earth, improving space weather forecasts and the Preparation of terrestrial infrastructures to extreme solar events.
