Two spacecraft have been launched on a mission to help scientists better understand the sun by creating artificial solar eclipses.

Proba-3, which includes two satellites, launched earlier this month from India by the European Space Agency. The mission will attempt a scientific feat by being the first to use a two-spacecraft configuration to observe the corona, the outer atmosphere of the sun.

Eclipses created by Proba-3 will not cast visible shadows on Earth, ESA says. But if successful, ESA and astronomers hope that the mission will answer several questionsincluding why the corona is hotter than the sun itself. The corona can reach 2 million degrees Fahrenheit, while the surface reaches 10,000 degrees. according to NASA.

“The ability of this mission to observe the corona so close to the sun for extended periods of time is an extraordinary opportunity,” Talwinder Singh, assistant professor of physics and astronomy at Georgia State University, told NPR. “If successful, this will pave the way for similar missions providing continuous, high-resolution observations of the solar corona.”

A better way to examine the sun

This isn’t the first time scientists have used artificial eclipses to study the sun, but some astronomers say this mission could achieve something that previous missions weren’t capable of.

Studying the solar corona is extremely difficult because it is obscured by light from the star’s surface, according to NASA. And one of the best ways to study the corona is during a total solar eclipse, when the moon passes between Earth and the sun and blocks the sun. During a total solar eclipse, the corona is visible. But total solar eclipses are rare, with the next one taking place in August 2026.

Several missions have studied the sun and created artificial eclipses, including ESA and NASA’s Solar Terrestrial Relations Observatory (STEREO) Mission who used a coronagraph to block the sun. But because the Sun’s surface is so bright, the instruments on these missions only block much of the lower part of the corona to reduce the amount of scattered light, according to Kathy Reeves, a senior astrophysicist at the Harvard & Smithsonian Center for Astrophysics .

“What’s interesting about the Proba-3 instrument is that the occulter is actually on a different spacecraft, so it can be quite far away, and with this technique the instrument can block the disk solar energy with more precision,” says Reeves.

The Proba-3 mission, which will fly in an elliptical orbit ranging from 372 miles to 37,000 miles above the Earth’s surface, is also revolutionary because it uses two separate spacecraft – one carrying the occulting disk and the ‘other the imaging camera, while previous missions had done so. used only one spacecraft, according to Talwinder Singh, assistant professor of physics and astronomy at Georgia State University.

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“Similar instruments, called coronagraphs, have been used in the past. However, traditional coronagraphs place the occulting disk on the same spacecraft as the imaging camera. This design has limitations, such as light diffraction, which limits the distance at which we can observe the sun,” says Singh.

During the Proba-3 mission, one satellite, the Occulter, will align with the sun and cast a shadow on the other spacecraft, the Coronagraph. The corona will be visible, as in a real eclipse, and the Coronagraph will take a photo of the inner part of the corona, according to the ESA.

The instruments will be spaced about 500 feet apart, longer than the length of an American football field, allowing scientists to get a closer view of the corona. It will also give scientists more time to study the sun, at least six hours for every 20 hours of orbit, compared to an actual solar eclipse than observed from Earth.

“Natural eclipses only happen once or twice a year, sometimes in inconvenient locations, like over the ocean, and they last only a few minutes,” Reeves says. “This mission is really exciting because it will extend the time scientists can study the Sun’s central corona from minutes to hours.”

The mission will not have a direct impact on Earth and false solar eclipses will not occur on Earth, Singh and Reeves say.

The first results of the mission will be available around four months after separation and synchronized flight of the spacecraft in early 2025, according to ESA.

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