The European Space Agency’s Solar Orbiter has been hit by a massive solar plasma eruption as it transited towards Venus.
Solar Orbiter is undertaking close-up studies of the Sun and the inner heliosphere – those parts of the solar system closest to our local yellow dwarf star – and will obtain imagery and data on the sun’s solar wind, magnetic field, and material eruptions. No craft has gone closer to the sun to achieve this.
On Sunday morning (UTC), Solar Orbiter had a close encounter with an eruption known as a Coronal Mass Ejection (CME) which burst from the Sun towards Venus and the ship.
CMEs are huge clouds of plasma and magnetic fields that erupt from the Sun’s corona. They can cause auroras and electromagnetic damage if they extend far enough to reach Earth.
Solar Orbiter is designed to withstand and monitor CMEs and has continued to along its journey since. Passing six thousand kilometres from Venus’ surface, the ship will use the planet’s gravity to alter its orbit to complete its next solar pass.
“The close approach went exactly to plan, thanks to a great deal of planning from our colleagues in Flight Dynamics and the diligent care of the Flight Control Team”, explains Jose-Luis Pellon-Bailon, Solar Orbiter Operations Manager.
When it returns to the Sun, the spacecraft’s closest approach will be about 4.5 million km closer than its last pass.
Solar Orbiter’s CME encounter has sent back some useful data.
Launched in 2020, Solar Orbiter’s job is to observe and monitor the sun’s activities – events like CMEs – and its instrumentation has obtained data that describes environmental changes around Venus after the ejection took place.
It detected an increase in solar particles – protons and electrons mainly – after the CME swept through.
While particles like these, and some ionised atoms such as Helium, are regularly spat out from the Sun, they can hitch a ride on plasma eruptions which will take them further into space.
It’s these instances that can prove dangerous to both astronauts and spacecraft which aren’t enclosed in Earth’s magnetic field – the protective shield that guards Earthlings from harmful solar radiation.
Being able to track the trajectory of solar emissions and alert space missions about extreme space weather events is important.
According to Alexi Glover from ESA’s space weather team, doing so helps keep humans and other biological entities as safe as possible from destructive space weather.
“Gathering data on events like this is crucial to understanding how they arise, improving our space weather models, forecasts and early-warning systems,” says Glover.
“Solar Orbiter is providing us with an excellent opportunity to compare our forecasts with real observations and test how well our models and tools perform for these regions.”
A previous CME was captured by Solar Orbiter in May.
Matthew Agius is a science writer for Cosmos Magazine.
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