Hidden in plain sight within the Sun’s glare is the ultra-hot yet ghostly faint solar corona, source of the solar wind and solar storms. The only way to see this key element of the Solar System is either through the remarkable cosmic coincidence that gives rise to total solar eclipses – the fact that the Sun is not only 400 times bigger than our Moon but also about 400 times further away, allowing it to cover the solar disc entirely – or else artificially, through Sun-obscuring telescopes.
The biggest and most ambitious of these ‘coronagraphs’ is about to become reality: ESA's Proba-3 mission involves two spacecraft forming one giant virtual instrument, with one spacecraft covering the Sun for the other. But how does it work in practice?
Enter formation flying
“Astronomers can’t outdo natural eclipses, but ‘external coronagraphs’ in both Earth and space do place the occulter as far from the telescope as possible. In space our practical options have been limited however; for instance, the LASCO-C2 coronagraph aboard the ESA-NASA SOHO solar observatory has its occulter just 70 cm away, within the spacecraft body.”
So what about flying the occulter on a separate spacecraft altogether, as far away as possible? Researcher Philippe Lamy led the Laboratoire d'Astrophysique de Marseille team which first devised the ASPIICS concept: “By moving them much further apart we’d be able to see much closer to the edge of the solar disc, so formation flying seemed a natural fit. It wasn’t an entirely new idea, because the US and Soviet Union had attempted it during the 1975 Apollo-Soyuz mission, when a cylindrical Apollo spacecraft blocked out the Sun for the watching Soyuz spacecraft – but the bright glare produced by propellant thrusting from the spacecraft spoiled the view.”
Enter formation flying
“Astronomers can’t outdo natural eclipses, but ‘external coronagraphs’ in both Earth and space do place the occulter as far from the telescope as possible. In space our practical options have been limited however; for instance, the LASCO-C2 coronagraph aboard the ESA-NASA SOHO solar observatory has its occulter just 70 cm away, within the spacecraft body.”
So what about flying the occulter on a separate spacecraft altogether, as far away as possible? Researcher Philippe Lamy led the Laboratoire d'Astrophysique de Marseille team which first devised the ASPIICS concept: “By moving them much further apart we’d be able to see much closer to the edge of the solar disc, so formation flying seemed a natural fit. It wasn’t an entirely new idea, because the US and Soviet Union had attempted it during the 1975 Apollo-Soyuz mission, when a cylindrical Apollo spacecraft blocked out the Sun for the watching Soyuz spacecraft – but the bright glare produced by propellant thrusting from the spacecraft spoiled the view.”
Enter formation flying
“Astronomers can’t outdo natural eclipses, but ‘external coronagraphs’ in both Earth and space do place the occulter as far from the telescope as possible. In space our practical options have been limited however; for instance, the LASCO-C2 coronagraph aboard the ESA-NASA SOHO solar observatory has its occulter just 70 cm away, within the spacecraft body.”
So what about flying the occulter on a separate spacecraft altogether, as far away as possible? Researcher Philippe Lamy led the Laboratoire d'Astrophysique de Marseille team which first devised the ASPIICS concept: “By moving them much further apart we’d be able to see much closer to the edge of the solar disc, so formation flying seemed a natural fit. It wasn’t an entirely new idea, because the US and Soviet Union had attempted it during the 1975 Apollo-Soyuz mission, when a cylindrical Apollo spacecraft blocked out the Sun for the watching Soyuz spacecraft – but the bright glare produced by propellant thrusting from the spacecraft spoiled the view.”
Enter formation flying
“Astronomers can’t outdo natural eclipses, but ‘external coronagraphs’ in both Earth and space do place the occulter as far from the telescope as possible. In space our practical options have been limited however; for instance, the LASCO-C2 coronagraph aboard the ESA-NASA SOHO solar observatory has its occulter just 70 cm away, within the spacecraft body.”
So what about flying the occulter on a separate spacecraft altogether, as far away as possible? Researcher Philippe Lamy led the Laboratoire d'Astrophysique de Marseille team which first devised the ASPIICS concept: “By moving them much further apart we’d be able to see much closer to the edge of the solar disc, so formation flying seemed a natural fit. It wasn’t an entirely new idea, because the US and Soviet Union had attempted it during the 1975 Apollo-Soyuz mission, when a cylindrical Apollo spacecraft blocked out the Sun for the watching Soyuz spacecraft – but the bright glare produced by propellant thrusting from the spacecraft spoiled the view.”
Enter formation flying
“Astronomers can’t outdo natural eclipses, but ‘external coronagraphs’ in both Earth and space do place the occulter as far from the telescope as possible. In space our practical options have been limited however; for instance, the LASCO-C2 coronagraph aboard the ESA-NASA SOHO solar observatory has its occulter just 70 cm away, within the spacecraft body.”
So what about flying the occulter on a separate spacecraft altogether, as far away as possible? Researcher Philippe Lamy led the Laboratoire d'Astrophysique de Marseille team which first devised the ASPIICS concept: “By moving them much further apart we’d be able to see much closer to the edge of the solar disc, so formation flying seemed a natural fit. It wasn’t an entirely new idea, because the US and Soviet Union had attempted it during the 1975 Apollo-Soyuz mission, when a cylindrical Apollo spacecraft blocked out the Sun for the watching Soyuz spacecraft – but the bright glare produced by propellant thrusting from the spacecraft spoiled the view.”
Enter formation flying
“Astronomers can’t outdo natural eclipses, but ‘external coronagraphs’ in both Earth and space do place the occulter as far from the telescope as possible. In space our practical options have been limited however; for instance, the LASCO-C2 coronagraph aboard the ESA-NASA SOHO solar observatory has its occulter just 70 cm away, within the spacecraft body.”
So what about flying the occulter on a separate spacecraft altogether, as far away as possible? Researcher Philippe Lamy led the Laboratoire d'Astrophysique de Marseille team which first devised the ASPIICS concept: “By moving them much further apart we’d be able to see much closer to the edge of the solar disc, so formation flying seemed a natural fit. It wasn’t an entirely new idea, because the US and Soviet Union had attempted it during the 1975 Apollo-Soyuz mission, when a cylindrical Apollo spacecraft blocked out the Sun for the watching Soyuz spacecraft – but the bright glare produced by propellant thrusting from the spacecraft spoiled the view.”
Enter formation flying
“Astronomers can’t outdo natural eclipses, but ‘external coronagraphs’ in both Earth and space do place the occulter as far from the telescope as possible. In space our practical options have been limited however; for instance, the LASCO-C2 coronagraph aboard the ESA-NASA SOHO solar observatory has its occulter just 70 cm away, within the spacecraft body.”
So what about flying the occulter on a separate spacecraft altogether, as far away as possible? Researcher Philippe Lamy led the Laboratoire d'Astrophysique de Marseille team which first devised the ASPIICS concept: “By moving them much further apart we’d be able to see much closer to the edge of the solar disc, so formation flying seemed a natural fit. It wasn’t an entirely new idea, because the US and Soviet Union had attempted it during the 1975 Apollo-Soyuz mission, when a cylindrical Apollo spacecraft blocked out the Sun for the watching Soyuz spacecraft – but the bright glare produced by propellant thrusting from the spacecraft spoiled the view.”
Enter formation flying
“Astronomers can’t outdo natural eclipses, but ‘external coronagraphs’ in both Earth and space do place the occulter as far from the telescope as possible. In space our practical options have been limited however; for instance, the LASCO-C2 coronagraph aboard the ESA-NASA SOHO solar observatory has its occulter just 70 cm away, within the spacecraft body.”
So what about flying the occulter on a separate spacecraft altogether, as far away as possible? Researcher Philippe Lamy led the Laboratoire d'Astrophysique de Marseille team which first devised the ASPIICS concept: “By moving them much further apart we’d be able to see much closer to the edge of the solar disc, so formation flying seemed a natural fit. It wasn’t an entirely new idea, because the US and Soviet Union had attempted it during the 1975 Apollo-Soyuz mission, when a cylindrical Apollo spacecraft blocked out the Sun for the watching Soyuz spacecraft – but the bright glare produced by propellant thrusting from the spacecraft spoiled the view.”
The biggest and most ambitious of these ‘coronagraphs’ is about to become reality: ESA's Proba-3 mission involves two spacecraft forming one giant virtual instrument, with one spacecraft covering the Sun for the other. But how does it work in practice?
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