A solar storm reaches the Solar Orbiter spacecraft flying over Venus

Sep. 5 () –

A huge solar coronal mass ejection (CME) reached the Solar Orbiter mission just two days before the spacecraft’s approach to Venus. for a gravity-assisted maneuver on its way to the Sun.

In the early hours of Sunday 4 September, the ESA/NASA Solar Orbiter mission flew by Venus. On August 30, a large coronal mass ejection shot out from the Sun in the direction of this planet. As data from Solar Orbiter continues to come in, this event reveals why ‘in situ’ monitoring of space weather and its effects on bodies and spacecraft in the Solar System is so important.

Fortunately, there were no negative effects on the spacecraft, as the solar observatory is designed to withstand and actually measure violent outbursts from our star, though Venus doesn’t always fare so well. Coronal mass ejections tend to erode Venus’s atmosphere, removing gases as they pass.

Solar Orbiter is a quarter of the way through its decade-long mission to observe the Sun up close and catch a glimpse of its mysterious poles. Its orbit was chosen to be in close resonance with Venus, meaning that it returns to the planet’s neighborhood every few orbits to use its gravity to alter or tilt its orbit.

This third flyby of Venus took place on Sunday at 01:26 UTC, when Solar Orbiter passed within 12,500 km of the center of the planet, which is about 6,000 km from its gaseous “surface”. In other words, It passed a distance half the width of the Earth.

Its distance from Venus, approach angle, and speed were meticulously planned to get the exact desired effect of the planet’s strong gravitational pull: bring it closer to the Sun than ever before.

“The close approach went exactly as planned, thanks to a great deal of planning by our colleagues in Flight Dynamics and the diligent care of the Flight Control Team,” he explains. it’s a statement Jose-Luis Pellon-Bailon, Solar Orbiter Operations Manager.

“By exchanging ‘orbital energy’ with Venus, Solar Orbiter has used the planet’s gravity to change its orbit without the need for large amounts of expensive fuel. When it returns to the Sun, the spacecraft’s closest approach will be about 4.5 million kilometers closer than before.”

Data returned since Solar Orbiter found the solar storm shows how its local environment changed as the large CME passed. While some instruments had to be turned off during its approach to Venus, to protect them from stray sunlight reflected off the planet’s surface, Solar Orbiter’s ‘in situ’ instruments remained on. recording, among other things, an increase in solar energetic particles.

The Sun emits particles, mainly protons and electrons, but also some ionized atoms such as helium. When particularly large flashes and ejections of plasma are fired from the Sun, these particles are picked up and transported with them, accelerated to almost relativistic speeds. It is these particles that pose a radiation risk to astronauts and spacecraft.

Improving our understanding of CMEs and tracking their progress as they move through the Solar System is a large part of Solar Orbiter’s mission. By looking at CMEs, the solar wind, and the Sun’s magnetic field, the spacecraft’s ten science instruments provide new insight into how the 11-year cycle of solar activity works. Ultimately, these findings will help us better predict periods of stormy space weather and protect planet Earth from violent outbursts from the Sun.

This recent CME illustrates a difficulty in space weather observations. As seen in this SOHO footage, a “full halo” is seen when a CME approaches Earth directly or, in this case, directly away from the “far side” of the Sun.

Determining whether coronal mass ejections are moving toward or away from Earth is tricky when viewed from Earth, because in both cases it appears to be expanding. One of the many benefits of the upcoming Vigil mission is that by combining images taken from the direction of Earth and Vigil’s position on the “side” of the Sun, the fifth Lagrange point, Distinguishing between an approaching or a receding storm will be easy and reliable.