Artificial solar eclipses in space: ESA’s revolutionary mission

ESA's Proba-3 mission uses two satellites to create artificial eclipses: a revolutionary technology that promises to reveal the secrets of the solar corona and improve understanding of space climate

Two satellites launched from India’s eastern coast on December 5 embarked on a very unique mission: that of creating artificial solar eclipses in space. Part of the European Space Agency’s Proba-3 mission, these revolutionary tools will profoundly change the way we will study the Sun. This will be history in the making because, for the very first time, scientists are going to have the capacity to study in detail the mysterious and fascinating region of the Sun called the corona.

Unraveling the mystery of the solar corona

Although located just above the Sun’s surface, the corona’s temperature reaches millions of degrees Fahrenheit, far hotter than the Sun’s visible surface, which is around 10,000°F. This baffling phenomenon defies our understanding of physics. The corona is also the birthplace of space weather events, such as solar flares and coronal mass ejections, which can disrupt communications, damage satellites, and even jeopardize Earth’s power grids.

So far, scientists have relied on those brief total solar eclipses to study this crucial area. Natural eclipses are very rare, though, and usually last only a few minutes, hence limiting the opportunities of research. Proba-3 promises to change that.

Two satellites, one perfect alignment

Proba-3 consists of two satellites: one will carry a disc to block sunlight, called the Occulter, while the other, called the Coronagraph, will study the corona from behind this artificial shadow. The satellites will fly separated by 472 feet in space and must act with the precision of millimeter-level synchrony. Reaching such an unprecedented level depends on advanced technology like gyroscopes, star trackers, and cold-gas thrusters.

It’s like kicking a soccer ball across a field and landing it precisely on a coin,” said Daniel Seaton, one of the lead researchers on the project.

These eclipses, occurring artificially between the satellites, won’t be observable from Earth, but in space, they will extend for as long as six hours-a gigantic extension of time compared with the very short spans of natural eclipses. Such on-demand eclipses will let scientists study extended solar events without having to rely on the rare alignment of Sun, Moon, and Earth.

Groundbreaking insights and future prospects

Data collected by Proba-3 will be distributed by ESA, enabling new opportunities for better understanding the processes in the solar corona and its effects at Earth.

Success could make this technology the cornerstone of more ambitious applications: to block light from other stars to discover distant planets and to explore stellar systems.