ESA’s Proba-3 Satellite to Create its Own Solar Eclipse

A new satellite will launch to form a solar eclipse on its own.

The European Space Agency (ESA) has announced its plan to launch the Proba-3, a double satellite that would allow them to induce solar eclipses. The satellite will be launched in 2019 with the goal of studying the Sun's corona.

According to ESA officials, the Proba-3 will be composed of an "occulter" satellite will fly 150 m ahead of a second" coronagraph satellite, which will cast a precise shadow to reveal the "ghostly tendrils" of the corona - the sun's outer atmosphere - down to a measurement of 1.2 solar radii.

In order for ESA scientists to measure the corona, the sun needs to be entirely covered solar eclipse-style, as the corona is one-million-times fainter than the sun. The Proba-3 is set to become the first precision formation-flying mission ever launched.

"We have two scientific instruments aboard," Damien Galano, Proba-3 payload manager said in a press release. "The primary payload is ASPIICS, a coronagraph to observe the corona in visible light while the DARA radiometer on the occulter measures the total solar irradiance coming from the Sun - a scientific parameter about which there is still some uncertainty."

The ASPIICS (Association of Spacecraft for Polarimetry and Imaging of the Corona of the Sun) instrument also has a smaller occulter disk, which will cut down on diffracted light that might spill from the main occulter's corners.

The concept behind the coronagraph was developed by astronomer Bernard Lyot during the 1930s, and has since been developed and incorporated into both Earth-based and space telescopes.

"Precision is all - the aperture of the ASPIICS instrument measures 50 mm in diameter," Galano said. "And for corona observation performance it should remain as much as possible in the center of the shadow, which is about 70 mm across at 150 m."

Galano also added that the same measuring approach could also be used in examining exoplanets.

"It's a similar challenge, the main difference being that the star in question is a point source of light rather than the extended source that our Sun is," Galano said.

"So it could be that formation-flown external occulters become versatile scientific tools, opening many new vistas in astronomy."