The European Space Agency (ESA) is preparing to launch the Proba-3 ‘double-satellite’ in 2019, with the aim of creating its own solar eclipses and studying the Sun’s corona.

Known to be the world’s first precision formation-flying mission, Proba-3 includes the occulter and coronograph spacecrafts .

Once launched, the occulter satellite will fly 150m in front of the second coronograph satellite, casting a precise shadow to reveal the tendril of the solar corona, which extends millions of kilometres into space and can easily be seen during a total solar eclipse.

The makeshift eclipse will reveal the solar corona down to an exact measurement of 1.2 solar radii.

Proba-3 payload manager Damien Galano said: “We have two scientific instruments aboard.

“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 corona is a million times fainter than the Sun itself, so the light from the solar disk needs to be blocked in order to see it."

“The corona is a million times fainter than the Sun itself, so the light from the solar disk needs to be blocked in order to see it. The coronagraph idea was conceived by astronomer Bernard Lyot in the 1930s, and since then has been developed and has been incorporated into both Earth-based and space telescopes.”

Currently being developed by a consortium led by Belgium’s Centre Spatial de Liège, the association of spacecraft for polarimetry and imaging of the corona of the sun (ASPIICS) has a 50mm aperture.

ESA noted that in order to observe corona, the aperture of the ASPIICS should remain as much as possible in the centre of the shadow of the sun.

Galano added: "So we’ll need to achieve millimetre-scale positioning control between the two spacecraft, effectively forming a single giant instrument across space.”

The external occulter spacecraft will also carry out the imaging of earth-like exoplanets, which would require the blocking out of their parent stars, during the eclipses.

Image: Rendering of Proba-3 revealing corona. Photo: courtesy of ESA-P.