Artificial Solar Eclipse Satellite Formation Captivates Scientists with Unprecedented Precision

A pair of European satellites has achieved a historic milestone by creating the world’s first artificial solar eclipses in space, thrilling scientists and opening new frontiers for solar research. The European Space Agency’s (ESA) Proba-3 mission, comprised of the Coronagraph and Occulter satellites, has demonstrated the ability to mimic a total solar eclipse on demand—an achievement previously thought impossible outside of rare natural events.

Launched in late 2023, the two satellites orbit Earth tens of thousands of miles above the surface. By flying just 492 feet (150 meters) apart, the Occulter satellite positions its 4.6-foot (1.4-meter) disk to block the sun’s bright face, casting a precise shadow onto the Coronagraph’s telescope. This alignment perfectly replicates the effect of the moon during a natural solar eclipse, allowing the Coronagraph to capture detailed images of the sun’s corona—the faint, wispy outer atmosphere that is otherwise obscured by the sun’s glare.

The feat requires extraordinary precision: the satellites must maintain their relative positions within just one millimeter, a distance comparable to the thickness of a fingernail. This is accomplished through a sophisticated suite of autonomous navigation technologies, including GPS, star trackers, lasers, and radio links. The entire formation-flying process is managed without ground intervention, highlighting the mission’s advanced onboard autonomy.

Since March 2025, Proba-3 has successfully produced ten artificial eclipses during its commissioning phase, with the longest lasting five hours—far exceeding the few minutes of totality provided by natural eclipses on Earth. Scientists anticipate achieving up to six hours of totality per eclipse when full scientific operations begin in July. Each artificial eclipse is generated once every 19.6-hour orbit, providing researchers with unprecedented flexibility and extended observation windows.

The mission’s first images, processed by the ASPIICS Science Operations Centre at the Royal Observatory of Belgium, have already drawn comparisons to those captured during natural eclipses. By combining exposures of varying lengths, scientists can construct comprehensive views of the solar corona, offering invaluable data for understanding solar dynamics, coronal heating, and space weather phenomena such as coronal mass ejections.

Proba-3’s success is not only a triumph of engineering but also a leap forward for solar science. The mission is expected to deliver over 1,000 hours of coronal imagery during its two-year duration, with all data made openly available to the scientific community and the public. Experts believe that this pioneering approach will pave the way for future satellite formations, enabling even more ambitious space exploration and research initiatives.

“Having two spacecraft form one giant coronagraph in space allowed us to capture the inner corona with very low levels of stray light in our observations, exactly as we expected,” said mission manager Damien Galano. “Although we are still in the commissioning phase, we have already achieved precise formation flying with unprecedented accuracy. This is what allowed us to capture the mission’s first images, which will no doubt be of high value to the scientific community”.