Two spacecraft align themselves for a spectacular display, capturing an awe-inspiring image and demonstrating cutting-edge technology during a solar eclipse simulation.
The European Space Agency's Proba-3 mission is making significant strides in the study of space weather by observing high-energy particles ejected by the Sun. This groundbreaking mission achieves this through a unique method: creating artificial solar eclipses.
The Proba-3 mission consists of two spacecraft that fly in precise formation, approximately 150 meters apart. The front spacecraft acts like the Moon during a natural eclipse, blocking the bright solar disk, casting a shadow onto the second spacecraft which carries a camera to image the Sun’s faint corona. This formation effectively forms an external coronagraph in space, enabling continuous, on-demand observations of the solar corona that are not possible during brief, geographically limited natural eclipses.
The key technological feat of Proba-3 lies in its ability to maintain millimeter-level alignment accuracy between the satellites while they orbit Earth at high speeds, up to 79,200 mph or 127,460 kph. This precision formation flying is a vital test for future space endeavours involving tasks like satellite docking, deorbiting defunct satellites, or deploying large-scale space telescopes with spatially separated components.
The scientific significance of Proba-3 lies in its ability to enable detailed and extended study of the Sun’s corona and related phenomena such as the generation of space weather events. Since solar storms can adversely affect Earth-orbiting satellites and technological infrastructure, better understanding of the coronal dynamics can help improve space weather forecasting and mitigate these risks. The artificial eclipse created by Proba-3 thus opens new frontiers in solar physics and space weather research by providing images and data that would otherwise be rarely accessible.
The primary functions of the two spacecrafts in the Proba-3 mission are to block and photograph the Sun during an artificial eclipse. The probe, launched in 2022, successfully took a picture of the Sun's corona in June 2025. The Sun's corona is difficult to study under normal circumstances due to its brightness, making Proba-3's images invaluable to scientists.
Space weather can cause the aurora on Earth and can harm Earth-orbiting satellites. Accurate predictions of space weather events are important to protect these satellites and to study space weather phenomena. The hope is that Proba-3 will help scientists better predict dangerous space weather events.
The Proba-3 satellites face challenges when trying to maintain precise formation flying due to their unique orbits. They approach Earth as close as 372 miles (600 kilometers) and reach more than 37,282 miles (60,000 km). Their speeds vary between 5,400 miles per hour (8,690 kilometers per hour) and 79,200 mph (127,460 kph). Despite these challenges, the mission is a testament to human ingenuity and the drive to explore and understand the mysteries of space.
It is important to note that Christopher Palma, a Teaching Professor of Astronomy & Astrophysics at Penn State, was not involved in this article beyond his academic appointment.
The Proba-3 mission could benefit future technologies that require accurate observations of the Sun's corona. By pushing the boundaries of what is possible in space exploration, Proba-3 is paving the way for a future where we can better understand and predict space weather events, ultimately protecting our technological infrastructure and improving our understanding of the universe.
The Proba-3 mission, with its precision formation flying of two satellites, serves as a crucial test for future space technologies such as satellite docking, deorbiting defunct satellites, and deploying large-scale space telescopes. The mission's success in obtaining images of the Sun's corona, a task normally challenging due to its brightness, demonstrates innovative advancements in space-and-astronomy and technology.
The improved understanding of the Sun’s corona, particularly its role in generating space weather events, is anticipated to boost the space economy by enhancing space weather forecasting and safeguarding Earth-orbiting satellites and technological infrastructure. This development champions the growth of the space economy by mitigating risks associated with dangerous space weather events and opening new frontiers in solar physics research.
