Leicester scientists look to Venus for close-range BepiColombo flyby

A black-and-white view of Venus from BepiColombo's previous flyby in October 2020. The spacecraft will travel much closer in August, just 500km from the planet's surface. Credit: ESA

Planetary scientists at the University of Leicester are braced for a flood of new data from one of the closest-ever flybys of Venus.

On August 10, the BepiColombo spacecraft will pass within just 500km of the planet’s surface, in the second of two gravity-assist manoeuvres on the way to mission destination Mercury.

Dr Beatriz Sánchez-Cano is one of only six guest investigators – and the only one based in the UK – for the European Space Agency (ESA) mission, and hopes the close-range observations of Venus’ atmosphere will help add to scientists’ understanding of the planet’s atmosphere, ionosphere and interaction with the Sun’s solar wind.

She said: “Planetary flybys give us unique perspectives of the planetary systems that can only be achieved with their special trajectories.

“In the case of Venus, we are very excited by this flyby because it will occur on the dayside and very close to the planet, which will allow us to investigate regions of the system not accessible to other Venus Orbiters, such as the long tail of the planet, the nature of plasma turbulence, or the possible detection of escaping minor ion species for the first time.

“This is a really unique opportunity for these observations.”

Venus is sometimes described as Earth’s ‘sister planet’ because of their similar size, mass, and bulk composition. But it is radically different to our home planet in other respects. It has the densest atmosphere of the four planets in the inner Solar System, resulting in exaggerated interactions with charged particles from the Sun as well as blistering temperatures of almost 500 degrees Celsius on its surface. 

Unlike Earth, Venus lacks a magnetic field, with its ionosphere the point of contact between the atmosphere with outer space and the solar wind. Scientists hope that observations from BepiColombo’s second flyby will reveal the planet’s ionopause, where this stream of high-energy plasma meet’s Venus’ distinct magnetic environment.

From BepiColombo’s previous flyby of the planet in October 2020 – and the first since NASA’s Parker Solar Probe in 2018 – Dr Sánchez-Cano and colleagues from BepiColombo teams in Austria, Germany, France, Japan and Sweden observed Venus’ magnetic field lines and its highly active magnetotail.

This tail – ‘blown’ by the solar wind away from the planet, and enhanced by a coronal mass ejection from the Sun shortly before the flyby – extends to around 48 Venus radii out into interplanetary space, or almost 300,000km.

Dr Sánchez-Cano and colleagues have also studied data captured in the cruise phase of the mission.

Scientists and astronomers from the University of Leicester’s School of Physics and Astronomy, and Space Park Leicester, have made significant scientific and technical contributions to the BepiColombo mission.

The spacecraft carries the Mercury Imaging X-ray Spectrometer (MIXS), developed by a Europe-wide consortium led by the University of Leicester, including institutes and companies in the UK, Finland, Spain, Germany and France.

MIXS will study the elemental composition of the surface of Mercury and its data will revolutionise our understanding of Mercury’s surface when it goes into orbit in 2025. The current Venus Flyby is the latest milestone of this exciting mission and will set the spacecraft on course for its first fleeting glimpse of Mercury in October.