“Unlocking Solar Secrets: Satellites Set to Craft Man-Made Eclipses for Stellar Research”

A duo of spacecraft has been launched on a mission aimed at enhancing scientists’ comprehension of the sun by generating artificial solar eclipses.

Proba-3, which consists of two satellites, was launched earlier this month from India by the European Space Agency. This mission endeavors to accomplish a scientific breakthrough by being the first to utilize a dual-spacecraft arrangement to scrutinize the corona, the sun’s outer layer.

The eclipses produced by Proba-3 will not create shadows visible from Earth, the ESA asserts. However, if successful, the ESA and astronomers expect the mission to resolve several inquiries, including why the corona is hotter than the sun itself. The corona can reach 2 million degrees Fahrenheit, while the surface is about 10,000 degrees, according to NASA.

“The capability of this mission to examine the corona so closely to the sun for extended durations is a remarkable opportunity,” Talwinder Singh, assistant professor of physics and astronomy at Georgia State University, informs NPR. “If achieved, it will pave the way for analogous missions that offer ongoing, high-resolution observations of the sun’s corona.”

An enhanced method to analyze the sun

This is not the first instance in which scientists have used artificial eclipses to investigate the sun, but some astronomers assert that this mission could accomplish what previous missions failed to do.

Investigating the sun’s corona is exceedingly challenging due to its obscured visibility caused by the brightness of the star’s surface, as stated by NASA. One of the most effective ways to examine the corona is during a total solar eclipse, when the moon aligns between Earth and the sun, blocking its light. During such an eclipse, the corona becomes visible. However, total solar eclipses are infrequent, with the next occurrence scheduled for August 2026.

A number of missions have investigated the sun and created artificial eclipses, including the ESA and NASA’s Solar Terrestrial Relations Observatory (STEREO) mission, which utilized a coronagraph to obstruct the sun. Nonetheless, due to the sun’s intense brightness, the equipment in those missions could only obstruct a significant portion of the lower corona to mitigate scattered light, as explained by Kathy Reeves, senior astrophysicist at the Center for Astrophysics Harvard & Smithsonian.

“What is intriguing about the Proba-3 instrument is that the occulter is positioned on a separate spacecraft, allowing it to be quite distant, making it possible for the instrument to block the sun’s disk more accurately,” Reeves states.

The Proba-3 mission, which will take place in an elliptical orbit ranging from 372 miles to 37,000 miles above Earth’s surface, is also revolutionary because it employs two distinct spacecraft—one carrying the occulter disk and the other housing the imaging camera, whereas previous missions utilized only a single spacecraft, as noted by Talwinder Singh, assistant professor of physics & astronomy at Georgia State University.

“Comparable instruments, referred to as coronagraphs, have been employed in previous studies. However, conventional coronagraphs place the occulter disk on the same spacecraft as the imaging camera. This configuration faces limitations, such as light diffraction, which constrains our ability to observe near the sun,” Singh explains.

During the Proba-3 mission, one satellite, the Occulter, will align with the sun and cast a shadow onto the other spacecraft, the Coronagraph. The corona will be observable, just as during a real eclipse, and the Coronagraph will capture an image of the inner section of the corona, as reported by the ESA.

The instruments will maintain a distance of approximately 500 feet apart, exceeding the length of an American football field, enabling scientists to have a closer observation of the corona. Additionally, this will afford scientists extended time to examine the sun, amounting to at least six hours in every 20-hour orbit, in contrast to the brief duration of natural solar eclipses witnessed from Earth.

“Natural eclipses occur only once or twice annually, and often they take place in less accessible locations, such as over the ocean, lasting only a few minutes,” Reeves remarks. “This mission is quite fascinating as it significantly increases the duration scientists can observe the sun’s middle corona from minutes to hours.”

The mission is not intended to directly affect Earth, and the artificial solar eclipses will not project down onto Earth, as stated by Singh and Reeves.

The first findings from the mission are expected to be available approximately four months after the spacecraft separate and operate in synchronization in early 2025, according to the ESA.