Studying the Sun can be made easier by eclipsing it, and the ESA, the European Space Agency, is preparing to launch an innovative mission that involves creating an artificial eclipse by positioning two satellites in formation around our Star. A first in the study of the Sun!
We have all seen images of the latest solar eclipse in North America. This exceptional event is of great interest for studying our Star, but it is rare on Earth. Fortunately, there is a scientific instrument to artificially block the solar disk and study the corona and the Sun’s exosphere.
How do eclipses work? Franck Menant explains everything in this episode of Futura in the Stars. © Futura
The Proba 3 Mission
ESA’s Proba missions are primarily technology demonstration missions. In this case, Proba 3 will test the ability of two satellites to fly in formation and position themselves relative to each other extremely accurately.
The two Proba 3 satellites will position themselves relative to the Sun so that the shadow of the first satellite is projected onto the second. The Sun will thus be eclipsed by the first satellite! Such a maneuver requires a lot of precision in the satellites’ ability to locate themselves, orient themselves, and move.
The Largest Coronagraph in the Universe?
The two satellites will be 144 meters apart from each other. This configuration will allow them to create a coronagraph with a total length of 144 meters. The length is crucial as it will enable the observation of details at the edges of the solar disk like never seen before.
Of course, with the Moon being 384,000 kilometers away from us, the image precision is much better. But it is a rare, short event (5 to 10 minutes), and most of the time out of reach of good solar observation instruments that are too difficult to transport. The Proba 3 mission will allow for eclipses lasting several hours.
This is not the first time that ESA has considered using satellites in formation to significantly increase the size of scientific infrastructures. The agency plans to deploy the Lisa mission in 2032 to build in orbit Earth’s largest interferometer laser to detect gravitational waves. Proba 3 will launch next September.