NASA’s DAVINCI mission to Venus is scheduled to launch in 2029. A new paper describes this upcoming journey, a daring mission that could shed new light on the red-hot planet’s mysterious and potentially habitable past.
Upon arriving at the second planet from the sun, the probe will dive through Venus’ atmosphere and absorb its gases for about an hour before landing on the planet’s surface, according to the paper published in The Planetary Science Journal. DAVINCIA is designed to act as a flying chemistry lab, and it will use its built-in instruments to analyze Venus’ atmosphere, temperatures, pressure and wind speed, while snapping a few photos of its journey through planetary hell.
DAVINCI is an abbreviation for Deep Atmosphere Venus Investigation of Noble Gases, Chemistry and Imaging. three upcoming missions planned for Venus, much to the delight of Venus nerds like me. And honestly, it’s been a long time. NASA’s last mission to Venus, Magellan, arrived on the planet in 1989 and completed scientific operations in 1994. Since then, NASA has not dispatched a specialized Venus mission, even though the planet is super hot — literally and figuratively.
Why is NASA sending a mission to Venus?
Understanding Venus helps scientists get a better picture of our own planet. Venus and Earth may have started the same way; the two planets share the same size, mass and density. But today, Venus has temperatures as high as 880 degrees Fahrenheit (471 degrees Celsius), with a thick, carbon dioxide-rich atmosphere that traps heat the same way greenhouse gases do on Earth. It also has an eerie volcanic landscape. Something may have happened in the early history of Venus that caused it to develop in such cruel and inhospitable conditions, eventually becoming so drastically different from Earth.
“The atmosphere of Venus contains the chemical clues to understand a whole range of aspects of that planet, including what its initial composition was and how its climate has evolved over time,” said Paul Byrne, associate professor of Earth and Planetary Science at Washington University in St. Louis, who was not involved with the paper, wrote in an email. “The DAVINCI team in particular hopes to determine whether Venus really had oceans of liquid water in the past, and if so, when and why those oceans were lost.”
How will DAVINCI measure Venus’ atmosphere?
To do that, DAVINCI will travel some 38 million miles (61 million kilometers) to Venus. The spacecraft will first perform two flybys of the planet, the first taking place 6.5 months after launch. During these flybys, the spacecraft will analyze the clouds of Venus and measure the amount of ultraviolet radiation absorbed by the day side of the planet, as well as the amount of heat radiated from the Venusian night side (Venus is not tidally locked, but it has a very slow rotational speed).
About two years after launch, the DAVINCI probe, known as the Descent Sphere, will descend through Venus’ atmosphere and sample the various gases as it makes its way to the surface. The 0.91 m (1 m) long probe takes an hour to descend, experiencing higher temperatures and higher pressures the further down it goes.
“It turns out that the atmosphere of Venus is relatively soft at about 55 km [35 miles]but quickly gets hotter and much denser as you approach the surface,” Byrne said. “Not to mention the sulfuric acid clouds, although thankfully they tend to dissipate once you’ve fallen to a height of about 47 km [29 miles]†
The Descent Sphere is equipped with five instruments designed to measure and analyze the chemistry and environment of Venus’ atmosphere; these tools will hopefully paint a better and more in-depth picture of the layered atmosphere. The probe will begin interacting with Venus’ upper atmosphere when it reaches an altitude of 120 kilometers and will eject its heat shield when it is 42 miles (67 kilometers) above the ground. Once it dives beneath the thick cloud layer of Venus, about 30,500 meters above the surface, the probe will attempt to capture hundreds of images. The clouds of Venus envelop the planet and cover the surface of the planet, so these images will provide unprecedented images.
In addition to imaging the planet, the Descent Sphere probe will also breathe in some of its atmosphere. “The DAVINCI probe will have a small inlet on the outside of the pressure vessel (actually a large, metal sphere) through which samples of the atmosphere at different heights will be drawn into the spacecraft (or, really, pushed inwards when the pressure is outside). the probe begins to rise dramatically above the internal pressure),” Byrne said.
When it lands, the probe should not move faster than approximately 40 km/h (40 km/h). If it survives the atmospheric entry, the probe will — hopefully — land in the Alpha Regio mountains, which are about the size of Texas, according to the researchers behind the new paper. Under ideal conditions, the probe will operate for 17 to 18 minutes once it holds the landing, but there is no real need to operate on Venus, as all the precious data has already been collected during its atmospheric dive.
Is Venus habitable?
Although Venus is a less-than-ideal place for life today, scientists want to investigate whether the planet was ever habitable.
In September 2020, a group of scientists claimed that Venus may be signs of life in the clouds based on a detection of what may be phosphine in the atmosphere of Venus. Phosphine is considered a biosignature gas on Earth. However, the results were largely met with skepticism. But whether Venus was ever habitable in the past depends on whether the planet once harbored liquid water oceans, or whether it simply had a thick, steamy atmosphere.
“The DAVINCI probe will try to answer this question by measuring the proportions of different gases in the atmosphere,” Byrne said. “Those measurements, in turn, will help scientists understand which of their climate and interior evolution models are correct, and thus what Venus’ likely planetary history is — including whether it was ever truly habitable.”
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