BepiColombo Probe Lifts the Veil of Venus Our neighbouring planet loses oxygen and carbon to space
Joint press release with the Space Research Institute (IWF) Graz
An international team of researchers led by the French Laboratory of Plasma Physics (LPP/CNRS) describes new findings about the atmosphere of Venus in the journal “Nature Astronomy”. Using observations from the BepiColombo space probe, in which the Institute of Geophysics and Extraterrestrial Physics (IGEP) and the Institute for Computer and Network Engineering (IDA) of TU Braunschweig are also involved, carbon and oxygen ions have been detected for the first time in the planet’s magnetic environment. The results have been published in Nature Astronomy.
Mysterious planet Venus
Unlike Earth, our neighbouring planet Venus has no magnetic field of its own. As a result, the stream of particles emanating from the Sun, known as the solar wind, interacts directly with the upper atmosphere of Venus, stripping it of charged particles and allowing them to escape into space. Previous measurements by space probes such as Venus Express had already shown that these ions are mainly composed of oxygen and hydrogen. However, the mass resolution of the instruments used at the time was not sufficient to distinguish between carbon, nitrogen and oxygen.
Mercury probe BepiColombo flies by Venus
On its way to Mercury, the BepiColombo space probe will need to fly past Earth, Venus and Mercury itself, as well as an electric propulsion system to finally swing into Mercury’s orbit against the Sun’s powerful gravitational pull. On 10 August 2021, the space probe flew past Venus for the second and final time.
On this occasion, BepiColombo came within 552 kilometres of the planet’s surface. Many of the instruments on board were active during the flyby, collecting unique data from the Venusian environment. For example, IDA’s Ion Mass Spectrometer (MSA) detected a stream of low-energy carbon and oxygen ions. “The magnetic field measurements complement these particle measurements beautifully and show that these particles are indeed flowing out of the Venusian magnetosphere,” says co-author Daniel Heyner, a member of the IGEP magnetometer group. IGEP built the magnetic field sensors in Braunschweig and is responsible for their operation, including data processing.
Some scientists believe that Venus had liquid water on its surface 700 million years ago. However, a catastrophic greenhouse effect caused the surface to heat up so much that all the water evaporated and escaped from the atmosphere. Today, the atmosphere of Venus is about 97% carbon dioxide. The discovery of the carbon particle stream by the BepiColombo space probe provides important information about the composition and dynamics of Venus’s magnetosphere and could help explain the past and future evolution of its atmosphere. The electrons escaping from the planet create an electric field that is thought to pull the carbon and oxygen ions out of the Venusian atmosphere.
The IGEP on board BepiColombo
The BepiColombo twin space probe is a collaboration between the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA). IGEP is involved in the magnetic field measurement instruments on both space probes – Mio (Magnetospheric Orbiter) and MPO (Planetary Orbiter). IGEP contributions have been funded by the German Space Agency at the German Aerospace Center.
“It is great that the years of intensive work on our magnetometers are already bearing fruit before BepiColombo has even reached its destination. Together with the scientists at the institute, I am very excited to see what the instruments will reveal about Mercury’s magnetosphere and its interior,” says Daniel Heyner.
“Scientists around the world are excited about these measurements from BepiColombo during the Venus flyby. The new data will allow further research into the evolution of planetary atmospheres, magnetospheres and their interaction with the solar wind,” says Professor Ferdinand Plaschke, leader of the working group at IGEP.
Why space research matters
BepiColombo is the first European mission to Mercury, carried out in collaboration with the Japan Aerospace Exploration Agency (JAXA) under the leadership of the European Space Agency (ESA). Launched on 20 October 2018, the twin space probe is on a seven-year journey to the smallest and least explored terrestrial planet in our Solar System. When it arrives at Mercury at the end of 2025, the high-tech instruments on board will collect high-precision data for at least a year, despite temperatures of over 350°C, which are eagerly awaited on Earth.
Mercury is the only planet in the Solar System that, like the Earth, has a solid surface and generates a magnetic field with its liquid core. The instruments on board the two BepiColombo space probes will precisely measure this magnetic field and its influence by the solar wind, in order to study Mercury’s internal structure, to explore differences and similarities with the Earth’s core, and to better understand the internal structure of our own planet.