ESA Proba-3 mission unlocks secrets of solar wind

This week’s total solar eclipse offered a rare glimpse of the sun’s white corona, glowing around the moon’s dark outline—a sight that has shaped solar science for generations.

Now, scientists no longer have to wait for the moon to create this rare opportunity.

The European Space Agency’s Proba-3 mission is making artificial solar eclipses possible by flying two spacecraft in precise formation for up to five hours at a stretch. This approach gives scientists an extended, unobstructed view of the corona, and early findings are already shedding light on the solar wind.

Traditionally, the only way to study the sun’s corona has been during a total solar eclipse, when the moon blocks the sun’s bright disk.

Proba-3 uses two separate spacecraft that fly in formation with outstanding precision, keeping their positions within just a few millimeters across a distance of 472 feet.

While a natural total solar eclipse usually lasts only a few minutes in any one place, Proba-3 can create a space-based eclipse that lasts up to six hours each orbit.

This extended view allows scientists to monitor subtle changes in the solar corona over much longer periods than a brief natural eclipse. Understanding how the solar wind forms and accelerates remains one of the biggest mysteries within solar physics.

The mission is helping researchers study the solar wind, a stream of superheated plasma that can reach temperatures above 1 million degrees Celsius.

Since its first artificial eclipse in orbit, Proba-3 has already surprised researchers with its results. For more than a century, total solar eclipses have led to major scientific advances, including the famous 1919 observation that confirmed Einstein’s general theory of relativity.

ESA Proba-3 mission unlocks secrets of solar wind with artificial eclipses