The European Space Agency’s Proba-3 mission creates artificial solar eclipses in space, allowing scientists to study the Sun’s corona for hours at a time. On August 10, 2026, ESA confirmed that the mission had completed its 62nd artificial eclipse, a impressive advance in solar research.
Proba-3 consists of two satellites flying in precise formation about 150 meters apart. Occulter carries a 1.4-meter disk that blocks the Sun’s direct light and casts a narrow shadow onto Coronagraph, the second satellite. Within this shadow, the ASPIICS instrument captures high-resolution images of the Sun’s corona, something previously possible only during brief natural eclipses.
Precision in Orbit
Maintaining the artificial eclipse requires extraordinary accuracy. The two satellites must keep their relative positions within a millimeter, using a system built around star trackers and GPS, with radio links and LED-tracking cameras working alongside specialized sensors. A laser system on Occulter bounces off a reflector on Coronagraph to ensure millimeter-level alignment. This precision keeps the telescope within the eight-centimeter-wide shadow, preventing stray sunlight from overwhelming the faint corona.
Hours of Continuous Observation
Unlike natural eclipses, which last only minutes, Proba-3 can sustain an artificial eclipse for up to six hours per orbit. Each orbit lasts nearly 20 hours, with the formation maintained more than 60,000 kilometers above Earth to minimize disturbances and fuel consumption. By April 2026, Proba-3 had logged more than 250 hours of continuous high-resolution video of the solar corona, equivalent to thousands of ground-based eclipse campaigns.
This extended observation time has already yielded new insights. Researchers have tracked slow solar wind structures moving at speeds between 250 and 500 kilometers per second, challenging previous models that estimated much lower velocities. Monitoring the corona for hours is impressive to understanding solar phenomena such as coronal mass ejections, which can disrupt satellites and communications. They can also affect power grids on Earth.
Spain’s Leading Role
Proba-3 is funded with a budget of €200 million under ESA’s GSTP program. Spain is the largest contributor, providing 38% of the funding, followed by Belgium at 34%. Spanish companies Sener Aerospace and Redwire Space, along with Airbus Defence and Space, contribute to the mission’s systems and formation-flying technologies; GMV also has a basic role. The project highlights Spain’s growing influence in the European space industry.
The mission’s technological achievements extend beyond solar science. Proba-3 demonstrates that multiple spacecraft can operate as a single instrument with millimeter precision for hours, opening new possibilities for future space missions that require distributed scientific payloads.
As ESA continues to refine the technology, artificial eclipses may become a standard tool for solar research, giving scientists a flexible way to study the Sun’s most elusive regions without relying on the rare alignment of the Moon and Sun.
