Proba-3 fills the solar observation gap
Proba-3 Fills the Solar Observation Gap: A Breakthrough in Space-Based Astronomy
The European Space Agency's (ESA) Proba-3 mission has been making waves in the space-based astronomy community since its launch in December 2024. This ambitious project has achieved not one, but two world firsts: the first precise formation flight and the first artificial solar eclipse in orbit. The resulting data have confirmed Proba-3's ability to provide the missing puzzle piece in our observations of the Sun's enigmatic atmosphere – the corona.
The Missing Piece: Observing the Inner Corona
Until now, space-based instruments have only been able to reliably image the solar disc and the outer region of the corona. The full corona could only be observed from Earth during the short periods of total eclipses. Although total eclipses are not entirely impossible to make, any observations of the inner coronal region have been infrequent or inconsistent, leaving us with an observation gap. This gap has hindered our understanding of the solar wind and coronal mass ejections (CMEs), which are crucial for predicting space weather events.
Proba-3 Delivers: Filling the Gap with Artificial Solar Eclipses
Thanks to a set of onboard positioning technologies that allow the Proba-3 duo to create a solar eclipse in orbit, the mission is delivering on its promise to fill this gap. The satellite duo has already created more than 50 artificial solar eclipses in orbit since the mission operations began less than a year ago. The resulting data confirm Proba-3's ability to provide detailed images of the inner coronal region, enabling scientists to advance their understanding of how the solar wind accelerates and how CMEs are triggered.
A Time-Lapse Animation: Capturing a CME in Action
The time-lapse animation below captures a CME in the top right, combining observations made over one hour and a half on 16 July by three different European instruments aboard different missions: the Sun's disc and low corona (artificially coloured in yellow), as captured by an extreme-ultraviolet telescope (SWAP) aboard Proba-2; the outer corona (in red) observed by the LASCO C2 coronagraph aboard SOHO; and the inner corona (in green), imaged in detail by Proba-3's ASPIICS coronagraph, filling the gap.
The Power of Proba-3: Observing the Inner Corona with Unprecedented Detail
Andrei Zhukov from the Royal Observatory of Belgium, Principal Investigator for the ASPIICS coronagraph aboard Proba-3, comments: "You can see the CME forming at the edge of the solar disc, captured by Proba-2. It extends into the inner coronal region, which is now visible to us thanks to Proba-3, before reaching the high corona observed by SOHO. The continuity with which we can now observe the CME structure extend outwards from the Sun is incredible."
Artificial Eclipses on Demand: A Game-Changer for Space-Based Astronomy
"Our artificial eclipse images are comparable with those taken during a natural eclipse," adds Andrei. "The difference is that we can create our eclipse once every orbit, which takes 19 hours and 40 minutes, while total solar eclipses only occur naturally around once, very rarely twice a year. On top of that, natural total eclipses only last a few minutes, while Proba-3 can hold its artificial eclipse for up to 6 hours."
The Implications of Proba-3: A New Era for Space-Based Astronomy
Joe Zender, Proba-3 project scientist, adds: "So far, the mission's observation time has amounted to about 250 hours across 50 orbits. This means these past few months alone deliver the same amount of data we could get from 6000 total eclipse campaigns on Earth." The implications of Proba-3 are far-reaching, with the potential to revolutionize our understanding of the Sun and its effects on the Solar System.
A Year of Proba-3: Achievements and Future Prospects
One year ago, on 5 December 2024, the two Proba-3 spacecraft launched to orbit, where they were carefully separated six weeks later. In March this year, the satellite duo performed its first autonomous formation flight. Demonstrating the degree of precision achieved, the two spacecraft that make up the Proba-3 mission – the Coronagraph and the Occulter – use their formation flying time to create artificial solar eclipses in orbit.
Conclusion: Proba-3 Paves the Way for a New Era in Space-Based Astronomy
The Proba-3 mission has achieved a major breakthrough in space-based astronomy, filling the gap in our observations of the Sun's corona. With its ability to create artificial solar eclipses in orbit, Proba-3 has opened up new possibilities for scientists to study the Sun and its effects on the Solar System. As we look to the future, Proba-3 will continue to play a vital role in advancing our understanding of the Sun and its place in the universe.
