ESA’s Solar Orbiter takes its closest look at the sun to date

28 Mar 2022

High resolution image of the sun taken from the Solar Orbiter at a distance of 75m km.. Image: Solar Orbiter/EUI team (ESA and NASA), E Kraaikamp (ROB)

The ESA said the spacecraft will gradually raise its orientation in future orbits to view the sun’s previously unobserved polar regions.

The Solar Orbiter – which aims to unlock the secrets of the sun – has taken its closest approach to our parent star to date. On 26 March, the spacecraft began passing at about one-third of the distance between the Earth and the sun.

After passing by the orbit of Mercury earlier this month, the Solar Orbiter began the next milestone of its journey, where the European Space Agency (ESA) and NASA spacecraft will use all its instruments to capture as much detail about the sun as possible.

“This is just the start. Over the coming years the spacecraft will repeatedly fly this close to the sun,” the ESA said in a statement. “It will also gradually raise its orientation to view the sun’s previously unobserved polar regions.”

It is expected that the Solar Orbiter – which has strong Irish connections – will soon send back stunning images from the latest phase of its mission. Last week, the ESA released an image taken by the Solar Orbiter’s extreme ultraviolet imager on 7 March.

The agency said this is the highest resolution image of the sun’s full disc and outer atmosphere – the corona – received to date. The image was taken at a distance of roughly 75m kilometres, halfway between the Earth and the sun.

“In total, the final image contains more than 83m pixels in a 9,148 x 9,112 pixel grid,” the ESA said. “For comparison, this image has a resolution that is 10 times better than what a 4K TV screen can display.”

As well as taking high resolution images of the sun, the spacecraft is also recording data on the solar wind of particles that flow outwards from the sun.

Launched in February 2020, the Solar Orbiter made its first close pass of the sun in June that year, despite the challenges of operating it in the middle of the Covid-19 pandemic. Six of the spacecraft’s 10 instruments are for imaging, each studying a different aspect of the sun.

The Solar Orbiter published its first images of our parent star in July 2020, revealing that the sun is dotted with ‘campfires’, which could be mini explosions known as nanoflares.

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Leigh Mc Gowran is a journalist with Silicon Republic