Proba-3 Released the First Self-Eclipsed Image of the Sun’s Corona

On June 16, 2025, the European Space Agency (ESA) released the first image from a groundbreaking mission: the creation of an artificial total solar eclipse in space. The feature was accomplished by Proba-3, a pair of satellites flying in precise formation to block out the Sun’s blinding disk and reveal its elusive corona.

This faint, ghostly halo around the Sun has long fascinated scientists but remains frustratingly hard to study. Its shape constantly shifts with solar activity, and no computer model yet fully captures its dynamic behaviour.

*Solar corona viewed by Proba-3’s ASPIICS. Credits: ESA*

To overcome these challenges, ESA developed a bold two-spacecraft solution. One satellite acts as an occultor while the other carries a coronagraph, flying in formation to generate an artificial eclipse of the Sun.

The first image, taken on May 23, shows the Sun’s green-tinged inner corona in striking detail. Delicate, hair-like structures emerge from behind the artificial shadow, captured in visible light using advanced image processing techniques.

A double spacecraft mission to unveil the mysteries of the Sun’s corona

Proba-3 launched on 5 December 2024 aboard an Indian PSLV rocket from Satish Dhawan Space Centre, marking a historic ESA–ISRO partnership. The mission’s twin goals are to demonstrate precision formation flying and to enable extended observations of the Sun’s mysterious corona.

The two spacecraft, the Occulter and the Coronagraph, fly 144 meters apart, aligned with millimetric accuracy to simulate a total solar eclipse. This unique configuration merges the pair into a single virtual instrument that spans across space.

Proba-3 Occulter eclipsing Sun for Coronagraph spacecraft. Credits: ESA — *Proba-3 Occulter eclipsing the Sun for the Coronagraph spacecraft. Credits: ESA*

At the heart of the mission is ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun), a next-generation coronagraph designed to study the corona’s temperature, structure, and violent ejections in visible light. Supporting instruments include DARA (Davos Absolute Radiometer), which measures solar irradiance, and 3DEES (3D Energetic Electron Spectrometer), a high-fidelity electron spectrometer monitoring radiation belts.

Now that formation flying has been successfully demonstrated, Proba-3 will enter its primary science phase. Up to 50 artificial eclipses per year are planned, each lasting six hours, a dramatic leap from the fleeting minutes of natural eclipses on Earth.

Joining the fleet of solar mission spacecraft

A growing international armada of missions is now dedicated to studying our star’s behaviour from multiple vantage points, both near and far, in orbit and from deep space.

ESA Solar Orbiter, launched in February 2020, recently delivered the first-ever images of the Sun’s south pole in March 2025. Using Venus’ gravity assists, it reached 17° below the solar equator, providing valuable data on polar magnetic activity and plasma dynamics.

Solar Orbiter's view of the Sun's south pole. Credits: ESA — *Solar Orbiter’s view of the Sun’s south pole. Credits: ESA*

NASA Parker Solar Probe continues its record-breaking dive toward the Sun, closing within 7.3 million kilometres in 2024. Travelling at over 700,000 km/h, it samples the solar wind directly, complementing the Solar Orbiter’s observations of particle acceleration from afar.

China’s Advanced Space-Based Solar Observatory (ASO‑S, Kuafu‑1), launched in October 2022, is currently operating in a Sun-synchronous Earth orbit. It monitors solar flares, coronal mass ejections, and magnetic fields.

*An illustration of the ASO-S. Credits: CAS*

Looking ahead, several ambitious solar missions are on the horizon:

NASA’s IMAP (launching September 2025): Will study solar wind and energetic particle acceleration from the L1 point.
NOAA’s SWFO-L1 (September 2025): A companion mission to IMAP, focused on solar wind monitoring and real-time space weather forecasting.
ESA’s HENON (2026): A CubeSat demonstration mission aiming to enable early solar storm detection from deep space.
NASA’s MUSE (2027): Will investigate coronal heating and solar flares using extreme ultraviolet imaging and spectroscopy.
China’s Solar Polar Orbit Observatory (2029): Will fly a high-inclination orbit to provide rare direct views of the Sun’s poles.
ESA’s Vigil (around 2031): Will monitor the Sun from the L5 point, offering early warnings of space weather disturbances.
Solar Ring (concept phase): A proposed Chinese-led mission deploying multiple spacecraft around the Sun for continuous 360° monitoring.

Together, these missions mark a coordinated global effort to unravel the Sun’s mysteries and improve space weather forecasting for Earth and beyond.