Astrum
Уровень B2· 1045 слов
This is the corona. Our Sun’s outer atmosphere. This fiery hell can reach temperatures of 10 million °C.
But just 1,500 km beneath this inferno, the surface is significantly cooler. This arguably makes no sense.
How can the temperature increase as it moves away from the source? Surely that’s the wrong way round?
Known as the “coronal heating problem”, this is one of the greatest unanswered questions in astrophysics, and it’s been baffling scientists for decades.
Over the years, there’s been theories and clues about its cause, but it’s hard to get answers about something you can’t easily see - other than the occasional fleeting glimpse during solar eclipses.
So, the inner corona has remained largely unobserved. But in December 2024, all that changed. The European Space Agency launched two tiny satellites that together are revolutionising our understanding of the Sun; working in perfect synchrony to make the once invisible visible.
I’m Alex McColgan and you’re watching Astrum. Today, we’re heading into orbit with the Proba-3 mission, as its first findings are released.
We’ll explore how these two minisats have opened up a window into the Sun’s most inaccessible region and get to grips with the extraordinary engineering that makes flying in millimetre precision formation possible.
On 5th December 2024, ESA’s Proba-3 lifted off on a PSLV-XL rocket from Satish Dhawan Space Centre in Sriharikota, India.
This mission didn’t necessarily garner headlines, but it was quietly set to change the face of solar exploration, and break a few engineering records in the process, because Proba-3 isn’t just one satellite, but two.
This pair of fully autonomous mini-sats have to fly in millimetre-perfect formation, through a highly elliptic orbit of Earth, all whilst positioned one and a half football pitches apart. And that’s easier said than done.
Why would we want to do this you might ask? Well, they were being sent to study the Sun and one area in particular - the corona.
