Probe on a mission to the Sun to keep Earth safe
ESA and Nasa venture to set off on two-year journey tasked with limiting danger of super-storms
ANYONE gazing up at the English night sky on September 1, 1859, would have noticed a curious phenomenon, as the Northern Lights danced brightly above much of the country.
Days earlier, the Sun had started flinging a colossal wave of electrified gas and subatomic particles at Earth, sparking the largest geomagnetic storm ever seen. Dubbed the Carrington Event after the British astronomer who recorded it, the giant solar flare did not stop with an impressive light show, but wrought havoc on telegraph systems, showering startled operators with sparks, igniting piles of paper, and crippling communications.
The Southern Lights shone so brightly in Australia that gold miners woke up in the middle of the night and began making breakfast.
Yet while undoubtedly vexing for the Victorians, if a similar event happened today, the impact would be catastrophic, wiping out GPS systems, frying electricity grids, and potentially causing food shortages and blackouts.
So in order to mitigate the threat – and to learn more about our parent star – scientists are sending a spacecraft to the Sun. The Solar Orbiter probe, a joint venture between The European Space Agency (ESA) and Nasa, finally launches from Cape Canaveral, Florida, tomorrow after 20 years of planning.
It will begin a two-year journey towards the centre of the Solar System, from where it can orbit the Sun, observing the powerful outbursts of plasma that can bring such disruption.
Dr Robert Wicks, associate professor of space risk at University College London’s (UCL) Institute for Risk and Disaster Reduction, has helped design two of the instruments on board Solar Orbiter. “The Sun is always emitting this constant flow of hot gas called plasma and that travels out into the Solar System and some hits the Earth and causes space weather,” he said.
“What we don’t know is how it does that. The impact on the Earth in terms of space weather could be quite large. If we had a Carrington Event today, there are predictions there would be trillions of dollars of loss. You would have blackouts potentially, and the loss of satellites. Solar Orbiter will do the science that will help us understand the Sun better to build a better forecast.”
Constructed by Airbus in Stevenage, Hertfordshire, and carrying several British instruments, the probe will give unprecedented images of our star, helping predict dangerous solar flares in time for countermeasures to be implemented, such as grounding planes or backing up power plants.
Although extreme storms like the Carrington Event are rare, smaller flares have caused widespread disruption in recent times, with a geomagnetic storm leaving six million Canadians without power in 1989.
The Government is so concerned about space weather that is now listed on its National Risk Register.
Jan Wörner, director general of the ESA, told The Sunday Telegraph: “Without the Sun, life on Earth would not be possible, but at the same time the Sun is also the source of solar flares, which can endanger us. When solar flares hit the Earth they can disturb all electric and electronic installations. In 1859 there was no internet, no satellite, no electric network, just telegraph systems.
“Our modern world depends strongly on electrical and electronic installations, which can be affected. Typically, a storm may only last a few days but can be hugely disruptive to modern technology.
“Super-storms can cause power blackouts, take out satellites, disrupt aviation and cause temporary loss of GPS signals and radio communications.”
Solar Orbiter carries 10 instruments, six for inspecting the Sun’s surface, and a further four to measure the environment surrounding the crafts it is buffeted by, subatomic particles, the solar wind and magnetic fields.
When the measurements and images are compared, it should show scientists what is happening both on and off the
Sun’s surface at the same time, so they can see what triggers the plasma jets.
At its closest approach, the probe will be 30million miles (49million km) from the Sun, about the same distance as Mercury. Any closer and the onboard telescope would fry. Later in the mission the probe will use a gravity assist from Venus to alter its elliptical orbit so it can sweep over the poles.
It will be the first time anyone has ever seen the poles of the Sun, and that phase in 2021 is expected to give crucial insights into the “solar dynamo”, a process which is theorised to generate the star’s magnetic field, effectively turning it into an electric generator.
Sarah Matthews, professor of solar physics at UCL, has worked on two of Solar Orbiter’s instruments, one called Spice (Spectral Investigation of the Coronal Environment) and another named EUI (Extreme Ultraviolet Imager).
“It is the first time we’ve been able to observe the poles of the Sun, and that’s important because the reversal of the magnetic poles is the key to the solar dynamo, which is driving activity, and it will improve our understanding of solar cycles,” she said.
“It will be a real mission of discovery, more like a planetary encounter, and I think we will make big leaps forward in our understanding of the Sun.
“It’s a 4am launch but I will be setting my alarm, and fingers crossed we will be celebrating on Monday morning. After that we’ll just have to be patient.”
Flying so close to the Sun has proved extremely challenging for engineers, because of extreme temperatures and radiation. Solar Orbiter will face temperatures of up to 932F (500C), enough to melt lead. To protect it from its fiery quarry, the probe has a titanium heat shield coated in a special material called SolarBlack, which was initially developed for medical implants and allows the instruments to stay below the crucial 104F (40C).
In fact, the heat shield works so well that making sure the instruments do not freeze in the icy chill of space, has proved a headache for British scientists.
UCL has been forced to wrap one of its imagers in a blanket, similar to that used by marathon runners, and install a heater to keep it warm. For another imager, it is dazzling light from the Sun which has caused problems.
Dr Wicks, who has worked on the mission for a decade, added: “Normally when photographing something you try to gather as much light as you can, but this time we want most of the light to go out the of the camera because it will get too hot. It’s been a real engineering effort and we have come up with new deflector system because the instrument can’t look directly at the Sun.”
The launch has already been delayed twice, once because of a technical issue and once due to weather conditions. Hurricane forecasts have also threatened tomorrow launch, due at 4.03am.
Dr Andrzej Fludra, of the UK’s RAL Space Science and Technology Facilities Council, the instrument consortium lead for the Spice instrument, said: “We have never had such an array of instruments observing simultaneously and combining their data, to answer an overarching question, how the Sun creates and controls the heliosphere.”
‘When solar flares hit the Earth they can disturb all electric and electronic installations ... typically, a storm may only last a few days but can be hugely disruptive to modern technology’