ESA unveils images of the first artificial solar eclipse created by Proba-3
The first images and data from the Proba-3 mission, released by the European Space Agency (ESA), mark a significant milestone in the exploration of our Sun. At the heart of this breakthrough lies the Centre Spatial de Liège (CSL), the technological driver of the mission through its development of the cutting-edge ASPIICS instrument, onboard the satellite. The scientific data transmitted by the two spacecraft will be analysed by researchers at the Royal Observatory of Belgium (ROB).
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he unveiling of these first images and data by ESA was met with great emotion by the Belgian space community. The Proba-3 mission (PRoject for On-Board Autonomy) is based on an unprecedented concept: two satellites - the Coronagraph and the Occulter - flying in close formation (at a distance of 150 metres) to artificially recreate a solar eclipse in space. This unique configuration will enable scientists to observe the Sun’s corona with exceptional sharpness and very close to the solar limb.
At the core of the mission is ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun), an optical instrument developed under the responsibility of CSL. Since 2014, the CSL team has led the design of the complete system - optical, thermal, and mechanical - including assembly, calibration, environmental testing, and final alignment. CSL also developed a critical component: the internal occulter, a high-precision element essential for filtering out alignment errors between the satellites and mitigating the effects of light diffraction.
The coordination of the ASPIICS implementation at CSL was overseen by Cédric Thizy : “ASPIICS is the achievement of a European collaboration involving an industrial consortium of 15 companies/institutes from seven countries, led by CSL. It took seven years to deliver the instrument to ESA in 2021, a period full of management, technological and engineering challenges. The first light of ASPIICS was acquired a few days after the launch, on 17 December 2024, already showing its good performances, but at that time the two spacecraft were still in a stack configuration. This first image of the solar corona, acquired while the two spacecraft were autonomously flying in formation, confirms that ASPIICS is performing as expected. This demonstrates the quality of the work done by the consortium, we are a step further in a sense of accomplishment and excited to see how solar physics will benefit from these observations."
This image, taken in the visible light spectrum, shows the solar corona in the same way as a human eye would see it during an eclipse through a green, dark green and violet filter. Hair-like structures were revealed using a specialized image-processing algorithm. Bottom right: A grid shows the actual position of the Sun behind the mission's occulter, slightly off-center. | © ESA/Proba-3/ASPIICS
One of ASPIICS’s major scientific goals is to resolve a long-standing mystery: why is the solar corona - the outermost atmospheric layer of the Sun, only visible during solar eclipses - significantly hotter than the Sun’s surface? The instrument will also allow for the study of coronal mass ejections, powerful outbursts of solar material that can severely impact satellites, communication systems, and power grids on Earth, the effects that are collectively called “space weather”.
The scientific analysis of the data collected will be conducted by the Royal Observatory of Belgium (ROB), led by solar physicist Andrei Zhukov, who will oversee the interpretation of these unprecedented observations. “Proba-3 allows observing solar corona very close to the solar limb and with very low straylight. It is the combination of these two features that makes Proba-3 unique. But in addition to the precisely flying spacecraft, an outstanding telescope is needed to capture these images. ASPIICS is certainly up to the task. Its high-quality images will make Proba-3 a major source of the data for studies of solar corona, the place where space weather is born.”
Beyond the CSL and ROB, Belgium plays a central role at every stage of the mission: OIP was in charge of the develoment of the Focal Plane Assembly, the two satellites were assembled in Kruibeke, and mission operations are conducted from Redu, in the province of Luxembourg.
With this first artificial solar eclipse image and data already under scientific scrutiny, Proba-3 marks the dawn of a new era in solar observation and confirms Belgium’s position as a leading player in European space research.
Contact
Cédric Thizy
Andrei Zhukov
Published on 6/18/25
