NASA will return to Venus, where the temperature reaches 470 °: will they find life?


Venus hides a wealth of information that could help us better understand Earth and exoplanets (Photo: NASA)

NASA has selected two missions, named DAVINCI + and VERITAS, to study the "lost habitable" world of Venus. Each mission will receive about $ 500 million for development and both are expected to launch between 2028 and 2030.

 For a long time it was thought that there was no life on Venus, due to its extremely high temperatures. But late last year, scientists studying the planet's atmosphere announced the surprising (and somewhat controversial) discovery of phosphine. On Earth, this chemical is produced mainly by living organisms.


 The news sparked renewed interest in Earth's "twin", prompting NASA to plan next-generation missions to take a closer look at Venus' planetary environment, which could hint at living conditions.

 Conditions for life

 

Hubble telescope

 Since the Hubble Space Telescope revealed the large number of nearby galaxies, astronomers have become obsessed with searching for exoplanets in other star systems, especially those that appear habitable.

 But there are certain criteria for a planet to be considered habitable. It must have a suitable temperature, an atmospheric pressure similar to that of the Earth and available water.

 In this sense, Venus probably would not have attracted much attention if it were outside our solar system. Its skies are filled with thick clouds of sulfuric acid (which is dangerous to humans), the earth is a desolate backdrop of extinct volcanoes, and 90% of the surface is covered in red-hot lava flows.


 Despite this, NASA will search the planet for environmental conditions that may have supported life in the past. In particular, any evidence that Venus may have had an ocean would change all of our current models of the planet.

 And, interestingly, conditions on Venus are much less harsh at a height of about 50 km above the surface. In fact, the pressure at this point is reduced so much that conditions are much more similar to those on Earth, with breathable air and comfortable temperatures.

 If life (in the form of microbes) exists on Venus, this is probably where it is found.


 The DAVINCI + probe

Bill Nelson, NASA Administrator (Photo: REUTERS / Al Drago)


 NASA's DAVINCI + (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) mission has several scientific objectives, related to:

 -Origin and evolution of the atmosphere


 Its goal is to understand the atmospheric origins of Venus, focusing on how it first formed, how it evolved, and how (and why) it is different from the atmospheres of Earth and Mars.

 -Atmospheric composition and surface interaction

 It is about understanding the history of water on Venus and the chemical processes that take place in its lower atmosphere. An attempt will also be made to determine whether Venus ever had an ocean. Since life on Earth began in our oceans, this would be the starting point in any search for life.


 -Surface properties

 This aspect of the mission will provide information on the geographically complex tile regions of Venus (which have highly deformed terrain), and will investigate their origins and their tectonic, volcanic and weathering history.

 These findings could shed light on how Venus and Earth started out similarly and later diverged in their evolution.


 The DAVINCI + spacecraft, upon reaching Venus, will drop a spherical probe filled with sensitive instruments through the planet's atmosphere. During its descent, the probe will sample the air, constantly measuring the atmosphere as it falls and returning the measurements to the orbiting spacecraft.

 The probe will carry a mass spectrometer, which can measure the mass of different molecules in a sample. This will be used to detect any noble gases or other gases in Venus's atmosphere.

 In-flight sensors will also help measure the dynamics of the atmosphere, and a camera will take high-contrast images during the probe's descent. Only four spacecraft have returned images of the surface of Venus, and the last such photo was taken in 1982.

 VERITAS


 Illusion of a volcano on Venus


 For its part, the VERITAS mission (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy) will map the characteristics of the surface to determine the geological history of the planet and better understand why it developed so differently from Earth.

 Historical geology provides important information on ancient climate changes, volcanic eruptions, and earthquakes. These data can be used to anticipate the possible magnitude and frequency of future events.

 The mission will also try to understand the internal geodynamics that shaped the planet. In other words, we can build an image of the movements of the continental plates of Venus and compare it with that of Earth.

 In parallel with DAVINCI +, VERITAS will take high-resolution topographic images of the surface of Venus across the planet, mapping surface features, including mountains and valleys.

 At the same time, the Venus Emissivity Mapper (VEM) instrument aboard the orbiting VERITAS spacecraft will map surface gas emissions with such precision that it will be able to detect near-surface water vapor. Its sensors are so powerful that they will be able to see through thick clouds of sulfuric acid.

 A key insight into conditions on Venus

 The most exciting of these two missions is the orbit-surface probe. In the 1980s, four landers reached the surface of Venus, but were only able to operate for two days due to crushing pressure. The pressure there is 93 bars, which is the same as being 900 meters below sea level on Earth.

 Then there is the lava. Many lava flows on Venus stretch for several hundred kilometers. And the mobility of this lava can be favored by the average temperature of the planet's surface, of about 470 ° C.

 For their part, the “shield” volcanoes on Venus are an impressive 700 km wide at the base, but only 5.5 km high on average. The largest shield volcano on Earth, Hawaii's Mauna Loa, is only 120 km wide at its base.

 Information from DAVINCI + and VERITAS will provide crucial insight into not only how Venus formed, but how any rocky, living planet forms. At best, this will provide us with valuable markers for the search for habitable worlds outside our solar system.



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