The rarity of solar eclipses — around one every 18 months — provides a small window for scientists to research the phenomena, especially when you have to be in the right place at the right time to study them at all. The European Space Agency has come up with an ingenious way to get around this problem: launch a pair of satellites into orbit designed to create and analyse their own artificial eclipses.
Ruling out a giant metal disc to obscure the sun, Montgomery Burns-style, the ESA came up with Proba-3 — a pair of satellites, neither much bigger than a few metres. The larger of the two, coming in at 340kg, is called the “Coronagraph” and will serve as the recording instrument, while the 200kg “Occulter” is tasked with blocking the sun.
Once in space, around 600km above the Earth’s surface, the satellites will separate “into a safe relative tandem orbit”, according to the ESA’s fact sheet. The plan is to keep them around 150m apart and for six hours out of every 19.6 (the orbit time), Occulter will create an artificial eclipse for Coronagraph to look at.
Apart from looking awesome, the main goal of Proba-3 is to analyse the sun’s corona, according to the ESA:
The corona is … the source of the solar wind and space weather that can affect satellites and Earth itself, especially through the irregular eruptions of energy called ‘coronal mass ejections’.
With temperatures reaching more than a million degrees celsius, the corona is also much hotter than the relatively cool 5500°C surface of the Sun – a fact that seems to contradict common sense.
Sadly, it’ll be a little while before Proba-3 gets underway, with the launch date scheduled for the end of 2020. Something to look forward to along with regular old eclipses.