Space weather occurs when enhanced solar activity disturbs Earth’s magnetic field and atmosphere.
As well as emitting a continuous stream of magnetised plasma, known as solar wind, the sun also occasionally expels billions of tonnes of matter, threaded with magnetic fields. This matter expands outwards through space, in what are known as coronal mass ejections (CMEs).
If these huge clouds of matter pass over Earth, they can threaten satellites and aircraft, and disrupt GPS navigation systems, power grids and data and communication networks.
In 1989, for example, the entire province of Quebec in Canada suffered a power blackout for nine hours as a result of a solar storm. Similarly, a 2003 space weather event caused a blackout in Sweden, while an estimated 10 per cent of the entire satellite fleet suffered some sort of anomaly or malfunction.
A recent ESA study estimated the socio-economic cost of a single, extreme space weather event could be as much as €15bn.
Now a new ESA concept mission is hoping to provide accurate advanced warnings of such events. This would give power grid operators more time to take measures to protect their networks, for example, according to Emanuele Monchieri, project manager for the solar sentinel mission at Airbus UK, which is leading the development of the overall mission, including the spacecraft itself.
“We hope to increase the warning window, in order that we can intervene early on, so we have the time to put in place mitigation measures on the ground and in the air,” he said.
The spacecraft will be placed at a fixed point, away from the direct line between the sun and Earth, known as the 5th Lagrange point.
Coronal mass ejections typically travel at between 300-3000km/s, meaning there can be a very short window between detecting the event and it reaching Earth.
By placing the spacecraft at L5, which is at around a 60 degree angle from the sun-Earth line, it should allow operators to spot signs of a coronal mass ejection earlier, said Monchieri.
This position should also make it easier to monitor the direction of the coronal mass ejection. “It also allows us to estimate the speed of the coronal mass ejection early on, we can follow it from when it detaches from the sun until it arrives at Earth,” said Monchieri.
The mission also involves the Science and Technology Facilities Council’s (STFC) RAL Space department, which will be leading the development of instruments to observe the sun and the heliosphere. Meanwhile UCL Mullard Space Science Laboratory will lead the development of instruments to measure the solar wind.
“We will have a magnetograph and an ultraviolet imager, which will allow us to monitor the active regions on the sun - the sunspots - to investigate the magnetic field and potentially enable us to predict coronal mass ejection formation,” said Monchieri.
An atmospheric imager will monitor the Earth-sun line, allowing the spacecraft to detect the speed and direction of coronal mass ejections more precisely.
“We will also have an instrument that will allow us to understand the intensity of the coronal mass ejection, how powerful it is,” he said.
A competing spacecraft platform will be developed by OHB in Germany. At the end of the studies, in around 18 months’ time, ESA will select a final design for the spacecraft and instruments.
Nanogenerator consumes CO2 to generate electricity
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