NASA has chosen two missions called DAVINCI + and VERITAS to explore the “lost habitable” world of Venus. Each mission will receive approximately $ 500 million in development, and both are expected to launch between 2028 and 2030.
It has long been thought that Venus has no life due to 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 new interest in Earth’s “twin,” prompting NASA to plan state-of-the-art missions to take a closer look at Venus̵
Conditions for life
Ever since the Hubble Space Telescope discovered a huge number of nearby galaxies, astronomers have been obsessed with searching for exoplanets in other stellar systems, especially those that appear habitable.
But there are certain criteria for a planet to be considered habitable. It must have the appropriate temperature, atmospheric pressure, similar to ground and available water.
In this respect, Venus probably would not have attracted much attention if it were outside our solar system. Its sky is filled with thick clouds of sulfuric acid (which is dangerous to humans), the earth is a desolate background of extinct volcanoes, and 90 percent of the surface is covered with red hot streams of lava.
However, NASA will look for the planet’s environmental conditions that once sustained life. In particular, any evidence that Venus once had an ocean would change all of our existing patterns on the planet.
And interestingly, the conditions of Venus are far less harsh at an altitude of about 50 km (30 miles) above the surface. In fact, the pressure at these higher altitudes decreases so much that conditions become much more similar to Earth, with breathable air and light temperatures.
If life (in the form of microbes) existed on Venus, it could probably be found here.
The DAVINCI + probe
NASA’s DAVINCI + mission (Deep Atmosphere Venus Investigation of Noble Gasses, Chemistry and Imaging) has several scientific goals related to:
Origin and evolution of the atmosphere
It will aim to understand the atmospheric origins of Venus by focusing on how it originally formed, how it evolved, and how (and why) it is different from the atmospheres of Earth and Mars.
Atmospheric composition and surface interaction
This will include understanding the history of Venus’ water and the chemical processes that work in its lower atmosphere. He will also try to determine if Venus ever had an ocean. As life on Earth began in our oceans, it will become a starting point in any search for life.
This aspect of the mission will give an idea of the geographically complex regions of Tessera’s Venus (which have highly deformed terrain) and will explore their origins and tectonic, volcanic and atmospheric history.
These discoveries may shed light on the way Venus and Earth began in a similar way and then diverged in their evolution.
Upon arrival on Venus, the DAVINCI + spacecraft will launch a spherical probe full of sensitive instruments through the planet’s atmosphere. During its descent, the probe takes samples of the air, constantly measuring the atmosphere when it falls and returning the measurements back to the orbital spacecraft.
The probe will carry a mass spectrometer that can measure the mass of various molecules in a sample. This will be used to detect noble gases or other traces of gases in the atmosphere of Venus.
Flight sensors will also help measure atmospheric dynamics, and a camera will take high-contrast images as the probe descends. Only four spacecraft have ever returned images from the surface of Venus, and the last such picture was taken in 1982.
Meanwhile, the VERITAS mission (Venus radiation, radioscience, InSAR, topography and spectroscopy) will map surface characteristics to determine the geological history of the planet and further understand why it evolved so differently from Earth.
Historical geology provides important information about ancient climate changes, volcanic eruptions and earthquakes. This data can be used to predict the possible size and frequency of future events.
The mission will also seek to understand the internal geodynamics that have shaped the planet. In other words, we can build a picture of the continental motions of Venus and compare it to that of Earth.
In parallel with DAVINCI +, VERITAS will make high-resolution topographic images of the planet on the surface of Venus, mapping surface characteristics, including mountains and valleys.
At the same time, the Venus Emissivity Mapper (VEM) instrument aboard the VERITAS orbital spacecraft will map surface gas emissions with such accuracy that it will be able to detect near-surface water vapor. Its sensors are so powerful that they can see through thick clouds of sulfuric acid.
A key look at the conditions of Venus
The most exciting thing about these two missions is the orbit-surface probe. In the 1980s, four paratroopers reached the surface of Venus, but could only work for two days due to the crushing pressure. The pressure there is 93 bar, which is the same as 900 m below sea level.
Then there is lava. Many lava flows of Venus stretch for several hundred kilometers. And the mobility of this lava can be improved by the average surface temperature of the planet of about 470 ° C.
Meanwhile, the volcanoes on the “shield” of Venus are an impressive 700 km (435 miles) wide at the base, but on average only about 5.5 km. The largest shield volcano on Earth, Hawaii’s Mauna Loa, is only 120 km wide at the base.
There are only three bodies in our solar system with confirmed active volcanic volcanoes: Earth, Mars and Jupiter’s Io Moon. But recent research suggests that Idun Mons (pictured), a volcanic peak of Venus, may still be active.
The information received from DAVINCI + and VERITAS will give a decisive idea not only of how Venus formed, but also of how each rocky, life-giving planet is formed. Ideally, this will provide us with valuable markers to look for when searching for habitable worlds outside our solar system.
Gail Iles, Senior Lecturer in Physics, RMIT University.
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