Space Weather Satellite Set to Go Where No Mission Has Gone Before

ESA Set to Go Where No Mission Has Gone Before

ESA’s Sun-watching Proba-2 minisatellite shows the aftermath of 18 February 2014’s coronal mass ejection.

Living near a star is risky business, and positioning a spacecraft near the Sun is a very good way to observe rapidly changing solar activity and deliver early warning of possibly harmful space weather. ESA is now looking at doing just that.

On most days, our normally calm Sun goes about its business, delivering a steady and predictable amount of heat and light that keeps planet Earth and its humans ticking.

But just as the Sun drives weather on Earth, solar activity is responsible for disturbances in our space environment, dubbed ‘space weather.’

Besides emitting a continuous stream of electrically charged atomic particles, the Sun periodically sneezes out billions of tonnes of material threaded with magnetic fields in colossal-scale ‘coronal mass ejections.’


In this animation, ESA’s future space weather satellite is seen positioned away from the Earth–Sun line and monitoring a coronal mass ejection from the Sun.

These immense clouds of matter usually miss Earth, but if one reaches us it can disrupt Earth’s protective magnetic bubble and upper atmosphere, affecting satellites in orbit, navigation, terrestrial power grids, and data and communication networks, among other effects.

Getting a view of the action

Obtaining warnings of such events would be immensely helpful: a recent ESA study estimated the potential impact in Europe from a single, extreme space weather event could be about €15 billion.

As just one example, even moderate space weather events can affect electrical power grids that supply electricity to homes, hospitals and schools. Improved warning times for larger events would allow grid operators to take measures to protect their networks and ensure continued power delivery.

“One of the best ways to observe rapidly changing solar activity is to position a dedicated spacecraft slightly away from our direct line to the Sun, so that it can observe the ‘side’ of our star before it rotates into view,” says Juha-Pekka Luntama, responsible for space weather at ESA’s mission control center, Darmstadt, Germany.

ESA Mission Set to Go Where No Mission Has Gone Before

The Lagrange points associated with the Sun-Earth system. Lagrange Points are positions in space where the gravitational forces of a two-body system like the Sun and the Earth balance out, allowing a spacecraft to remain in position with reduced fuel consumption. The image includes a small icon representing NASA’s WMAP spacecraft orbiting around L2, which is about 1.5 million km from Earth. ESA missions orbiting Lagrange points include: ICE, LISA Pathfinder and SOHO at L1, and Herschel, Planck, Gaia at L2. Future ESA Lagrange point missions include JWST, Euclid and Plato (L2), while a study is under way for a future space weather mission at L5. Note: Image is not to scale

Virtual points in space

One of these, the 5th Lagrange point, lags 60º degrees behind Earth in its orbit – an ideal location for monitoring mass ejections from the ‘side’ so as to give early warning and better estimates of the speed and direction.

“L5 is an excellent spot for a future ESA space weather mission because it gives advance views of what’s happening at the Sun,” says Juha-Pekka.

“The spacecraft would provide crucial data that will help us spot Earth-arriving ejections, improve our forecasts of the arrival time at Earth and provide advance knowledge of active regions on the Sun as they rotate into view.”

Proba-2 Set to Go Where No Mission Has Gone Before

A rear view of Proba-2 as it looks towards the Sun. The Proba satellites are among the smallest ever flown by ESA, but they are making a big impact on space technology. Altogether, 17 technology developments and four scientific experiments are flying on Proba-2.

First-ever mission to L5

Today, ESA began studies to examine exactly this concept. Four European industrial and scientific consortiums including leading experts on space systems and instrument design will develop concepts for flying a mission to L5.

Based on the results, ESA will select a final design in about 18 months.

This space weather mission would provide data for operational applications such as forecasts and nowcasts of solar activity.

These are part of ESA’s Space Weather Service Network, which will issue warnings and alerts to scientific, commercial and civil customers when solar activity poses any risk to critical civil and economic activities.

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