Artificial eclipse satellite reconnects with Earth

The Proba-3 mission includes two ESA satellites Coronagraph and Occulter, launched into Earth orbit in December 2024. The pair of satellites create artificial eclipses to understand the corona, the outermost layer of the Sun’s atmosphere.

However, on February 14, the Coronagraph satellite encountered problems. A chain reaction causes it to lose direction and the solar cell turns away from the Sun, leading to energy depletion. The satellite then went into survival mode, with only some electronics working and data transmission to the ground interrupted.

On March 19, ESA Director Josef Aschbacher announced that “a miracle happened” because of reconnection with Coronagraph. Specifically, a group of ESA scientists in Spain discovered that a small amount of sunlight was shining on the panels while the Coronagraph rotated around. They seize the opportunity, using this little energy to reestablish the connection.

Finally, after more than a month of no news, ESA’s ground station in Spain received telemetry data, including information about temperature, voltage, and operating status of systems, from Coronagraph. The satellite’s solar battery points toward the Sun, allowing it to recharge. Experts are turning the device back on and checking the satellite’s operating status to see if there is any damage.

“Receiving feedback from Coronagraph is great news and brings great relief,” said Damien Galano, Proba-3 mission manager.

In the Proba-3 mission, two satellites Coronagraph and Occulter must fly in precise formation to simulate a solar eclipse at an altitude of more than 60,000 km above the Earth’s surface. Occulter is equipped with a 1.4 m diameter shield, acting as the Moon and blocking sunlight. Meanwhile, Coronagraph is in charge of observing the corona from the shadow region.

Proba-3 allows scientists to study the super-hot corona, which is more visible during a total solar eclipse. While total solar eclipses on Earth last only a few minutes and occur about 60 times a century, Proba-3 is capable of collecting 10-12 hours of observational data per week for two years. Observing the corona helps understand phenomena such as the solar wind and coronal eruptions (CMEs), which can disrupt electrical and communication systems on Earth.