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Two new NASA missions hope to answer important questions about Venus’ past. NASA/JPL/USGS
NASA is finally back on Venus. On June 2, 2021, NASA Administrator Bill Nelson announced that the agency had selected winners of the latest Discovery-class spacecraft mission competition, both heading to the second planet from the Sun.
I am a planetary scientist and I confess I am a evangelist of Venus, which is why I am so excited about humanity’s return to Venus.
This is the first time since the Magellan mission in 1989 that NASA has committed to sending a spacecraft to study the nearby planet. With the data that these two missions from Venus – called VERITAS and DAVINCI+ – will collect, planetary scientists can begin to tackle one of the solar system’s biggest mysteries: why Venus, a planet roughly the same size, density and age as Earth, is different from the world humanity calls at home?
Venus is cut in half with green-yellow clouds on the left and artists’ impression of what it might look like with oceans, clouds, and life on the right.
land wrong?
Venus is a rocky planet about the same size as Earth, but despite these similarities, it’s a wild place. Although it’s a little closer to the sun than Earth, the runaway greenhouse effect means it’s extremely hot on the surface — about 870 F (465 C), roughly the temperature of a self-cleaning oven. Surface pressure is a crushing pressure 90 times the sea level pressure on Earth. On top of that, there are clouds of sulfuric acid that cover the entire planet and corrode anything that passes through them.
But perhaps the most amazing aspect of Venus is that it may have looked a lot like Earth. Recent climate models indicate that in the past the planet would have had liquid water oceans and a temperate climate. It was probably habitable for as long as 3 billion years before it experienced some kind of climatic catastrophe that caused global warming. The goal of these two new missions to Venus is to try to determine if Venus is really Earth’s twin, why it has changed and whether large, rocky planets, in general, become habitable oases like Earth…or a scorching wasteland like Venus.
The story continues
A square satellite with two tall solar panels above the brownish planet Venus.
new eyes on flower
What may come as a surprise is that in the 1960s and 1970s, Venus was as central to space exploration as Mars is today. The United States and the Soviet Union sent more than 30 spacecraft in total to the second planet from the Sun. But since 1989, only two missions have gone to Venus, and both have focused on studying the atmosphere – the European Space Agency’s Venus Express and Japan’s Akatsuki.
In contrast, the VERITAS and DAVINCI+ missions will take a holistic view by exploring the geological and climatic history of Venus as a whole, in two very different but complementary ways.
The thick, global layer of sulfuric acid clouds covering Venus makes it nearly impossible to see the surface with regular cameras. That’s why the VERITAS Orbiter – short for Venus Emissivity, Radio Science, InSAR, Topography and Spectroscopy – will carry a powerful radar system. This radar can navigate through clouds and collect images and topographic data with a resolution up to 10 times higher than any previous mission to Venus. This will allow scientists to search for clues about Venus’s early climate that may have been preserved in rock formations at the surface and may also answer whether the planet is geologically active today. Finally, this exciting mission will use a special infrared camera to telescope through the atmosphere at very specific wavelengths to take the world’s first measurements of what the rocks of Venus are made of – something scientists don’t know much about.
A circular probe with sampling equipment falls toward Venus.
Veritas’ companion is DAVINCI+, or “Venus’ Deep Atmospheric Exploration of Noble Gases, Chemistry and Imaging.” The DAVINCI+ mission also includes an orbiter, but the real star of the show will be the meter wide Atmospheric Probe. The probe will plunge into Venus’s atmosphere and fall freely through thick clouds for about an hour before reaching the surface.
On the way down, you’ll sample the atmosphere, specifically measuring a variety of gases including argon, krypton, and xenon. The different climatic histories of Venus may result in different proportions of these noble gases in the atmosphere – thus by analyzing these proportions, scientists will be able to determine how much water the planet formed, and even how much water it has lost over the course of the Earth. last 4.5 billion years.
But that’s not all the probe will do. Before the probe hits its landing in an area called Alpha Regio that has some of the oldest rocks on the planet, the probe will take infrared images of the surface as it appears through the gloom of the lower atmosphere. These images will be the first to be taken from above the surface but below the cloud’s surface, showing planetary scientists like never before.
Artist’s impression of an exoplanet around a different star.
Now is the time to go back to Venus
I’ve argued before for a return to Venus, so to say I’m excited about these missions is an understatement. Venus may hold the key to understanding the past – and perhaps the future – of Earth. As astronomers discover more and more Earth-sized worlds around other stars, they need to understand whether the outcome we see on Earth — blue skies, watery oceans and even a thriving biosphere — is the norm, or whether the infernal wasteland of Venus is the norm. .
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Several decades of continuous exploration of Mars have shown that each mission answers previous questions and also raises new ones. I don’t know what surprises VERITAS and DAVINCI+, due to launch in late 2020, will reveal on Venus, but I do know that they will discover aspects of the planet that no one had imagined before. Scientists and expedition teams around the world have worked hard to achieve the “Decade of Venus,” and it’s paying off. In fact, just a week after NASA made the announcement, the European Space Agency announced its plans for a Venus mission as well. With these new missions, I believe – I hope – that we are at the beginning of a new golden age of Venus exploration.
This article is republished from The Conversation, a non-profit news site dedicated to exchanging ideas from academic experts. Written by: Paul K. Byrne, North Carolina State University.
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Paul K. Byrne does not work for, consult, own or receive funding from any company, organization or organization that would benefit from, consult, or receive funding from this article, and he has not disclosed any relevant affiliations after their academic appointment.
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