Europe’s first mission to explore Venus – Sciencetimes

beautiful planet venus

Venus, which is called the morning star in Korean, was named after Venus, the goddess of love and beauty in the West because of its beautiful appearance. The second planet in the solar system, Venus, at its brightest, has an apparent magnitude of approximately -4 to 5 magnitude. For this reason, Venus is the second brightest object visible from Earth after the sun and the moon.

Venus has an extremely high temperature of over 700K on average because its atmosphere is mainly composed of carbon dioxide and is very dense. Carbon dioxide creates a greenhouse effect, keeping the surface of Venus high. Venus’ atmosphere is completely different from Earth’s atmosphere.

Why are humans obsessed with Venus?

Venus has been one of the greatest interests of mankind since ancient times. Venus is often called Earth’s twin because it is slightly smaller than ours, but the planet’s atmosphere is quite different, as explained earlier. Humanity is beginning to ask questions about why planets of similar size and location have evolved in such different ways. However, Venus was a planet shrouded in many veils, and it was only a few decades ago that mankind began to dig deeper into Venus. If we can know more about Venus, where the greenhouse effect occurs, we can understand more about the greenhouse effect on our planet.

Also, Mars and Venus were the planets that started to attract the most attention when mankind began to wonder if there could be another life form somewhere in our solar system, which has been around for a long time. Although Earth is currently the only planet inhabited by life, recent simulation results by Dr. Michael Wei’s team at NASA’s Goddard Space Flight Center suggest that Earth may not be the first home of life, which is somewhat shocking. The results were published. According to the results of the research team, Venus, now turned into ruins, may have been a habitable planet billions of years ago, and it is speculated that the carbon dioxide Venus’ slow rotation made it a dead planet.

The Japanese unmanned probe ‘Akatsuki’ (あかつき: meaning dawn in Japanese)’ team is also skeptical about whether or not life lived on Venus, but it is speculated that Venus was similar to Earth in the past. it has been revealed

As if representing the popularity of this emerging topic, the European Space Agency recently selected EnVision, a Venus orbit mission that maps Venus as the fifth mission (M5 mission) of the M-class missions of the recent Cosmic Vision project. there is a bar The above selection was chosen over rivals such as SPICA and THESEUS, which shows how passionate Europe is for Venus exploration. If so, what kind of mission was Europe’s first exploration of Venus? What scientific results were obtained from the above mission, and why is Europe so passionate about exploration of Venus?

The first European mission to explore Venus was the Venus Express mission (also called VEX), launched in November 2005. This mission was first proposed in 2001 by a consortium led by Dr. Dimitri Titov, Dr. Emmanuel Lellouch and Dr. Fredric William Taylor. Interestingly, the above mission was originally initiated to recycle the main payload and design of the Mars Express mission, the first European Mars rover, in which the European Space Agency (ESA) and Russian space scientists jointly participated in other planetary missions. Of course, it cannot be used as it is. For example, Venus is much closer to the Sun than Mars (which leaves about a two-fold difference in distance), so it radiates about four times as much.

In this way, it was decided to change and apply the previous mission according to the environment of Venus, and the Venus Express mission, which started for the purpose of conducting scientific research by observing the atmosphere of Venus in a polar orbit around Venus for a long time, is more than any previous Venus mission. Planned to observe Venus for a long time. This is because long-term observations can provide hints about Earth’s climate change while understanding Venus’ atmospheric dynamics. Long-term observations of Venus have unraveled many mysteries about Venus, and the great success of the mission has put Europe in preparation for a more powerful Venus exploration mission.

Venus Express mission’s Venus observation image ⓒ Venus Express/ESA

Payload in Venus Express

Venus Express has a total of 7 payloads. The onboard ASPERA-4 (Analyzer of Space Plasmas and Energetic Atoms) for the purpose of observing and studying the interaction between the solar wind and the atmosphere of Venus and the interaction of the atmosphere and plasma was reused as is the ASPERA-3 design used in the Mars Express. It has been adapted for the harsh environment of Venus. The magnetometer, designated MAG, is intended to support ASPERA-4 in the study of the interaction of Venus’ atmosphere and solar wind, intensively examining the strength of Venus’ magnetic field. The MAG was designed based on the ROMAP instrument aboard the Comet Research Mission Rosetta’s lander. The Venus Monitoring Camera (VMC), a CCD camera mounted to map the brightness distribution of the surface of Venus, is mounted on Mars Express to study the distribution of Venus’ volcanic activity and upper atmospheric UV absorption using visible, ultraviolet, and near-infrared rays. It is an upgraded version of the Visual Monitoring Camera.

The on-board PFS (Planetary Fourier Spectrometer), operating in the infrared in the wavelength range of 0.9 µm to 45 m, for more detailed observations of Venus’ atmosphere, analysis of atmospheric components and aerosols, and investigation of interactions, is also built on the basis of the Mars Express spectrometer. one of the payloads. SPICAV (SPectroscopy for Investigation of Characteristics of the Atmosphere of Venus), derived from the SPICAM instrument flew by Mars Express, is a spectrometer for the investigation of Venus’ atmosphere, and VIRTIS (Visible and Infrared) is a thermal imaging spectrometer using visible and infrared light. Finally, Vera (Venus Radio Science) is an onboard payload to analyze the ionosphere and the atmosphere and surface of Venus.

Venus Express’s rover ⓒ Venus Express/ESA

The Venus Express was launched along with a Soyuz-FG/Fregat rocket from Kazakhstan on 9 November 2005 after a two-week delay to inspect small fragments of insulation on top of the rocket, as monitored by ESOC, ESA’s control center in Darmstadt, Germany. After 153 days of travel, it was confirmed that they had reached Venus on April 11, 2006. However, additional control was required for the Venus Express to enter the 24-hour orbit of Venus, and on May 7 of the same year, it finally entered its target orbit.

The Venus Express, which started with a 500-day mission planned at the time of launch, observed Venus very successfully, and was extended five more times, thus extending the mission until 2015. Venus Express, which studied Venus’s atmosphere, clouds, surface characteristics, and plasma in detail, was terminated on December 16, 2014, when transmission with Earth was cut off on November 28, 2014. The last signal from the spacecraft was detected on January 18, 2015.

Venus Express mission’s Venus observation image ⓒ Venus Express/ESA

Scientific discovery of Venus Express (1) – Venus’ ionosphere swells like the tail of a comet.

The Venus Express was the first European mission to Venus, but it was also one of the missions that brought humanity the most information about Venus. It is no exaggeration to say that the great success of the Venus Express became a catalyst for Europe to choose the Venus mission when choosing a new mission.

As such, Venus Express made several scientifically significant discoveries, particularly during periods of reduced solar wind pressure, when Venus’ ionosphere swells like a comet’s tail at night. The ionosphere is a layer of weakly charged gas above the planet’s atmosphere. They also found that the shape and density of the ionosphere are controlled in part by the planet’s internal magnetic field.

Venus’ ionosphere bulges like the tail of a comet ⓒ Venus Express/ESA/Wei et al. 2012

In August 2010, NASA’s Stereo-B spacecraft measured the solar wind density to be about 50 times lower than usual, which lasted about 18 hours. Venus Express took a close look at Venus at this time and observed a Venus ionosphere balloon that closely resembles the shape of a comet’s ion tail. The teardrop-shaped ionosphere began to form within 30 minutes to an hour after the normal high-pressure solar wind weakened, and Venus’s ionosphere expanded at least twice in two Earth days.

In the case of the Earth with a strong magnetic field, the ionosphere is relatively stable to changes in the solar wind, but Venus does not have its own internal magnetic field, so it has no choice but to rely on the interaction with the solar wind to form the ionosphere. It is still debatable whether this shape depends on the strength of the solar wind. However, the observations of the Venus Express are significant because they are the first to reveal the effect of very low solar wind pressure on the ionosphere of an unmagnetized planet and have resolved the debate about how solar wind strength affects the way Venus’ ionosphere plasma travels. have

The researchers expected similar effects to occur on Mars, another unmagnetized planet in our solar system. The Venus Express is an observation that shows that even as the solar wind decreases, the sun can still have a significant impact on the environment of neighboring planets.

Scientific Discovery of Venus Express (2) – Changes in Wind Speeds on Venus

Venus Express also made observations of changes in wind speed on Venus. Scientists tracked the movement of clouds at the top of the clouds about 70 km from the planet’s surface during the decade of Venus (6 Earth years), allowing them to monitor wind speed patterns.

This revealed that the winds of Venus are steadily increasing. When the Venus Express first landed on Venus in 2006, it was found that the average wind speed of the clouds between 50º latitude was estimated to be around 300 km/h, but increased to 400 km/h over the course of the mission, making it even faster. According to Dr. Igor Khatuntsev of the Moscow Institute of Space Research, this change has never been observed before and the origin of these wind speed changes is still controversial.

Scientific Discovery of Venus Express (3) – The Glory Phenomenon of Venus

Venus Express captured the beautiful glow of Venus in March 2014. It is thought to be a phenomenon in which the sun’s light is scattered by tiny droplets of clouds, similar to a rainbow. If the rainbow is arcuate, the glow refers to a ring-shaped continuum of various colors concentrated around a smaller, brighter nucleus. Glory can only be observed when the observer is positioned between the sun and the particles of the cloud. It is predicted that the 1200 km-spreading glory is caused by UV absorption, but further research is still needed.

Glory phenomenon discovered on Venus ⓒ Venus Express/ESA

Scientific Discovery of Venus Express (4) – Venus and Water

Scientists speculate that about 4 billion years ago, Venus may have had a lot of water. However, the origins of Venus’ atmosphere and the scarcity of water are still not fully known. Currently, the main component of Venus’ atmosphere is carbon dioxide, and it is known that a very small amount of water was caused by the runaway of Venus’ greenhouse effect caused by carbon dioxide and the temperature increase due to the evolution of the sun. Therefore, Venus Express wanted to make additional observations to determine why Venus is running out of water.

The Venus Express team found that an electric field strong enough to deplete oxygen, one of the key components of water, exists in Venus’ upper atmosphere. If an electric field exists, the solar wind, a powerful stream of charged subatomic particles from the sun, can remove hydrogen ions (protons) and oxygen ions from the planet’s atmosphere. These are the main raw materials for making water, so it could be the answer to why there is little water on Venus. The electric field of Venus is at least five times larger than expected, and it became a hot topic as it was the first measured among all planets in the solar system.

Venus is closer to the sun than Earth, so it gets more ultraviolet light. It is believed that this could create a greater number of free electrons in the atmosphere and, consequently, a stronger electric field on the planet. In particular, the above study is considered to be a significant discovery that can be applied not only to our solar system but also to exoplanetary systems as a discovery that supports the mechanism of water loss in planets close to the pond star.

Scientific Discovery of Venus Express (5) – Active Volcanic Activity on Venus

Finally, Venus Express made headlines when it discovered strong evidence of Venus’s active volcanic activity. Observing the surface or surface of a planet is extremely difficult due to its thick atmosphere. Even on a planet with a thick atmosphere, such as Venus, it is even more difficult. Combining observations from the Venus Express team with radar observations from previous missions, the scientific truth is that Venus is a planet covered by volcanoes and ancient lava flows.

Do volcanoes really exist on Venus? ⓒ ESA

Venus has long been thought to have an internal heat source because it is similar in size as well as volume to Earth. It has been predicted that the internal heat source must escape in some way, but one possibility is in the form of a volcanic eruption. Venus Express, which has been observing only Venus for eight years, has produced various observations to answer the above important question.

The team interprets these as coming from relatively fresh lava flows that have not undergone significant surface weathering, suggesting that these flows are less than approximately 2.5 million years old. However, the team could not answer whether Venus still has active volcanoes.

Evidence of active volcanic activity on Venus © Venus Express/ESA

Additional evidence discovered by the team in 2012 revealed that the upper atmosphere’s sulfur dioxide content increased sharply between 2006 and 2007, followed by a gradual decline over the next five years. Of course, this could have been caused by a change in wind speed patterns, but the researchers interpreted that volcanic activity moved huge amounts of sulfur dioxide into the upper atmosphere. The team mapped the heat emission of Venus’ atmosphere using near-infrared imaging of the VMC onboard the probe, and found local changes in surface brightness in the results above just a few days apart.

According to Dr. Eugene Shalygin, a Venus scientist at the Max Planck Institute for Solar System Research (MPS) in Germany, he observed several times that a point on the surface of Venus suddenly became very hot and then cooled again. The region of Venus (near the Ozza Mons and Maat Mons volcanoes and the GanikiChasma region of Venus) is a crustal fissure zone, but it is the first time that daily temperature changes have been detected.

In particular, the vicinity of one of the ‘hot spots’ of the Ganiki Chasma Rift is only about 1 square km in size and the temperature is expected to be 830°C, much higher than the average Venus temperature of 480°C. This could be very indirect evidence of active volcanic activity on Venus. According to the research team, Venus is still actively changing, so it is very important evidence for understanding the evolution of Venus.

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