In a groundbreaking milestone for solar science and satellite technology, the European Space Agency’s (ESA) Proba-3 mission has released its first images of the Sun’s elusive outer atmosphere — the solar corona. These high-resolution images were captured using a unique two-satellite formation that creates artificial solar eclipses in space, a feat never achieved before.
This is an image of the Sun during an artificial solar eclipse. Against a black background, the Sun’s bright body is covered by a black disc, and light green hair-like tendrils extend from the black disc in all directions. Brighter green light peeks from behind the black disc’s edge, slowly fading towards the outer edges of the image.]
CREDIT
ESA/Proba-3/ASPIICS/WOW algorithm
In March, ESA’s Proba-3 mission accomplished a spaceflight first: two spacecraft — the Coronagraph and the Occulter — flew 150 meters apart in flawless coordination, maintaining alignment to within a millimeter without any ground control. This precision enabled them to simulate a total solar eclipse by positioning a 1.4-meter disc aboard the Occulter to block the Sun’s glare, casting an 8 cm
shadow onto the Coronagraph’s telescope.
The two spacecraft of Proba-3 fly in precise formation about 150 m apart to form an external coronagraph in space, one spacecraft eclipsing the Sun to allow the second to study the otherwise invisible solar corona. CREDIT-ESA-P. Carril
This artificial eclipse allowed the ASPIICS instrument (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun) to capture the solar corona in unprecedented clarity, free from the blinding light of the solar disc. Developed by a European industrial team led by Belgium’s Centre Spatial de Liège, ASPIICS is opening new frontiers in observing solar phenomena.
The solar corona — a halo of superheated plasma extending millions of kilometers into space — holds answers to some of solar science’s biggest mysteries. Strangely hotter than the Sun’s surface, this region plays a vital role in space weather, particularly in the creation of coronal mass ejections (CMEs) that can disrupt communications, navigation systems, and power grids on Earth, as witnessed in May 2024.
“Seeing the first data from ASPIICS is incredibly exciting,” said ESA project scientist Joe Zender. “It will help us address longstanding questions about the Sun and improve our understanding of solar activity.”
Thanks to its orbital eclipse setup, ASPIICS drastically reduces stray light, allowing it to detect fine details in the inner corona that are usually missed by traditional coronagraphs. The instrument captures each image by combining three separate exposures, creating a dynamic range that reveals both faint and bright structures.
“These artificial eclipses are comparable to natural ones,” said ASPIICS Principal Investigator Andrei Zhukov. “But unlike rare total eclipses on Earth, Proba-3 can recreate them every 19.6 hours, and for up to six hours at a time.”
While Proba-3 remains in its commissioning phase, the mission has already demonstrated exceptional performance. “This is the world’s first precision formation flying mission,” noted Dietmar Pilz, ESA Director of Technology, Engineering and Quality. “The technologies that made this possible were developed under ESA’s General Support Technology Programme.”
Mission manager Damien Galano added, “We’ve already achieved sub-millimetre autonomous formation flying — the key to our successful eclipse imaging. The next step is reaching full autonomy, where no ground monitoring is needed at all.”
The continuous stream of coronal data from Proba-3 is transforming how scientists simulate solar phenomena. Institutions across Europe are refining their computer models using real observations for validation. One such model, COCONUT, developed at KU Leuven and integrated into ESA’s Virtual Space Weather Modelling Centre, is already using Proba-3’s images to enhance predictive capabilities.
“Proba-3 is filling a critical gap in solar data,” said Jorge Amaya, ESA’s Space Weather Modelling Coordinator. “It lets us simulate digital eclipses down to the Sun’s edge — something previously only possible during brief natural eclipses.”
Launched on December 5, 2024, aboard an Indian PSLV-XL rocket from Sriharikota, India, Proba-3 is managed by ESA and a consortium of over 29 companies from 14 countries. Led by Spain’s Sener, with major contributions from GMV, Airbus Defence and Space, Redwire Space, and Spacebel, the mission is setting a new standard in both satellite coordination and solar research.
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