Will Proba-3 call home? European solar eclipse satellite goes dark

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Europa has lost contact with one of its two Proba-3 spacecraft, after an anomaly caused the vehicle to lose its orientation.

The European Space Agencyits (ESA) Proba-3 mission launched into Earth orbit from India in December 2024. Proba-3 consists of two spacecraft designed to fly in precise formation to create artificial solar eclipses in space, so that scientists can study the Sun’s tenuous outer atmosphere, or corona. But the mission could be in jeopardy after an anomaly that occurred over the weekend of February 14 caused one of the probes to lose its orientation.

The incident involved Proba-3’s Coronagraph vehicle, which is responsible for imaging the Sun’s corona. Its partner, the Occulter spacecraft, blocks out the bright disc on the Sun’s face for the Coronagraph to image the corona without the intrusion of blinding light from the star. To do this, both spacecraft must fly in formation approximately 500 feet (150 meters) apart while maintaining alignment within millimeter accuracy. Losing control of either vehicle would effectively end the Proba-3 mission.

The spacecraft Proba-3 went into their exact station holding formation in May 2025, demonstrating for the first time ever the ability for two spacecraft to remain in such synchrony. Then, in June 2025, the mission took its first pictures an artificial solar eclipse.

Now ESA is trying to find out exactly what went wrong last month. – The root cause of the anomaly is under investigation, and mission teams are working hard to restore the situation, says the agency said in a March 6 update.

Diagram of Europa's two Proba-3 formation flying satellites in space, with the Sun in the background

Diagram of Europe’s two Proba-3 formation flying satellites in action. (Image credit: ESA-F. Zonno)

diagram of two spacecraft orbiting the Earth, with the Sun in the distance

Illustration showing the highly elliptical orbit of Europa’s two Proba-3 satellites. (Image credit: ESA — P. Carril, 2013)

The anomaly caused an apparent chain reaction that prevented Coronagraph from entering safe mode and led to a “progressive loss of attitude,” the ESA update said. The change in orientation pointed the spacecraft’s solar panels away from the sunquickly drain the batteries and trigger a “survival mode.”

While searching for a cause, mission operators are investigating how to safely steer the Occulter probe closer to the Coronagraph to help diagnose the problem and reestablish contact. ESA officials said they would provide updates “as new information becomes available.”

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