The first images from the European Space Agency’s (ESA) Proba-3 mission are offering an unprecedented look at the mysterious outer atmosphere of the Sun, marking a significant milestone in the mission’s solar studies using a novel technique: creating artificial eclipses in space.
Launched last December, Proba-3 consists of two spacecraft that fly in a precise formation that allows them to simulate the conditions that occur during a solar eclipse approximately ever 19.6 hours.
Allowing scientists viewing windows of close to six hours during each artificial eclipse, the new images of the Sun’s corona were captured with Proba-3’s ASPIICS coronagraph instrument.
These unprecedented views of the Sun offer a unique extended viewing opportunity of solar dynamics that occur during eclipses. The early images not only validate the mission’s innovative technologies, but also help to open new avenues toward understanding solar physics and improving space weather forecasting.
A Closer Look at the Corona
The Sun’s corona has long puzzled solar scientists. One reason for this has to do with the perplexing reasons behind why the Sun’s outer atmosphere is hotter than its surface.
Enter the Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun, or ASPIICS, which was specially designed to scour this curious region of the Sun in greater detail than any past effort with the help of precision formation flight between the two Proba-3 spacecraft that induce light-blocking similar to what occurs naturally during an eclipse.
“Seeing the first data from ASPIICS is incredibly exciting,” said Proba-3 project scientist Joe Zender, who explained that the data will help tackle enduring questions about solar behavior when paired with measurements from the mission’s other instruments: the DARA (Digital Absolute Radiometer), which monitors the Sun’s total energy output, and 3DEES, which studies electron activity in Earth’s radiation belts.
“Together with the measurements made by another instrument on board, DARA, ASPIICS will contribute to unravelling long-lasting questions about our home star,” Zender said in a statement that appeared at the ESA’s website.
Andrei Zhukov, the team’s Principal Investigator, said he was “thrilled” by the inaugural images produced by Proba-3. “Now we are working on extending the observation time to six hours in every orbit,” he added.
Precision Formation and Artificial Eclipses
Each of the images produced by Proba-3 are composites of three separate exposures, allowing ASPIICS to capture both the bright inner corona and its fainter, outer structures. The mission’s success relies mainly on the precision formation maintained between the two individual spacecraft, which is attained through autonomous operations that are monitored by an ESA ground team.
“Many of the technologies which allowed Proba-3 to perform precise formation flying have been developed through ESA’s General Support Technology Programme, as has the mission itself,” said Dietmar Pilz, ESA’s Director of Technology, Engineering and Quality.
“It is exciting to see these stunning images validate our technologies in what is now the world’s first precision formation flying mission,” Pilz said. Ultimately, the team hopes to achieve completely autonomous formation flight that will require no additional monitoring from the ground.
Advancing Digital Simulations
Going beyond its imaging capabilities, Proba-3 is also helping scientists obtain critical data for next-generation solar models. Recently, institutions that include KU Leuven have already begun using early data from the Proba-3 mission to help refine existing simulations involving digital eclipses.
Additionally, ESA’s Virtual Space Weather Modeling Centre integrates KU Leuven’s COCONUT software with other models, allowing scientists to track and predict how various solar phenomena may affect Earth, and offering new tools for both researchers and space weather forecasters more precisely.
“This huge flow of observations will help refine computer models further,” said Jorge Amaya, ESA’s Space Weather Modelling Coordinator.
As a joint effort between the ESA and an industrial consortium led by Spain’s Sener that includes a range of European commercial partners, Proba-3 is already proving to be a transformative solar science mission, with its digital eclipses enabling high-resolution access to the Sun’s most mysterious regions for the first time.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. He can be reached by email at micah@thedebrief.org. Follow his work at micahhanks.com and on X: @MicahHanks.