NASA, ESA TO RETURN TO VENUS
Three probes will voyage to our sister planet by the early 2030s.
After leaving Venus in relative neglect for almost three decades, the U.S. and Europe are gearing up to mount a set of robotic expeditions that will give us our most comprehensive view yet of Earth’s acidic sister.
On June 2, NASA administrator Bill Nelson announced the agency would send two new missions to Earth’s inner neighbor by 2030. One of them, DAVINCI+, is a probe that will fall through Venus’ atmosphere, sampling its caustic clouds and snapping closeups of its terrain. The other, VERITAS, will study the planet from orbit with state-of-the-art radar and imagers.
Eight days after NASA’s statement, the European Space Agency (ESA) announced it had greenlit EnVision, another orbiter that will arrive at Venus in the early 2030s to study both its surface and its oppressive atmosphere.
The news thrilled many in the planetary science community who have been clamoring for decades for a renewed focus on Venus and its geology. The last NASA mission to target the planet was the Magellan probe, which orbited Venus from 1990 to 1994. Although the hellish world often serves as a flyby waypoint for spacecraft seeking a gravitational slingshot to more distant locales, its only dedicated visitors in the last 27 years have been ESA’s
Venus Express and Japan’s Akatsuki
(or “Dawn”), both of which studied the planet’s atmosphere.
NASA’s decision to double down on Venus surprised even the mission teams. DAVINCI+ and VERITAS were competing in a pool of four proposals under NASA’s program of low-budget ($500 million) Discovery-class missions. NASA had said it would approve up to two proposals.
“Everyone hoped that one of the two slots would be a Venus mission,” says Justin Filiberto, a member of the DAVINCI+ team and a geochemist at the Lunar and Planetary Institute in Houston. But choosing both, he says,
“is incredible because it makes a mini Venus exploration program.”
DAVINCI+ is short for Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging; the plus sign was added when the mission’s proposal was revised and enhanced in 2019. VERITAS’ full name is Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy.
COMPLEMENTARY CRAFT
While Venus has long taken a backseat to Mars in planetary exploration, over the past few decades, scientists have come to realize that the landscape beneath Venus’ perpetual layer of clouds could once have been similar to Earth’s — and perhaps even supported life. A major objective of the new missions will be to understand why these planets’ fates diverged. And one major reason for scientists’ excitement is that the trio of craft complement each other’s capabilities.
When DAVINCI+ hits the venusian cloud tops, it will become the first
NASA mission to directly probe Venus’ atmosphere since 1978, and the first from any nation since the USSR’s Vega missions in 1985. As it falls, it will piece together a complete profile of Venus’ atmosphere, layer by layer.
It will also sniff out interesting compounds — perhaps even phosphine, which was detected by radio astronomers last year to much fanfare. On Earth, phosphine is thought to be produced in large quantities only by microbes, which led the team to float the possibility that Venus’ clouds could harbor life. However, after a data-processing error was discovered, the team decreased its estimate of phosphine levels, opening the door to other interesting geochemical processes that could explain what’s occurring in Venus’ extreme atmosphere.
Although DAVINCI+ is not designed to survive its hard landing on the surface of Venus, it will send images of the terrain from below the cloud deck as it descends toward the Alpha Regio highlands. Scientists hope to learn whether the rocks in the region — an area roughly twice the size of Texas — are made of continental granite or volcanic basalt. Granite would imply that water was present in the interior of Venus, while basalt can be produced without water. “So that tells a very different story about habitability,” says Filiberto.
Meanwhile, from orbit, VERITAS will try to decipher Venus’ surface geology with radar, and probe its interior by measuring the planet’s gravity field. EnVision will study Venus’ surface and atmosphere with European-built spectrometers, as well as look just beneath the surface with a ground-penetrating radar sounder. It will also carry a radar built by NASA’s Jet Propulsion Laboratory, which is managing VERITAS. Together, the two craft will provide a global picture of Venus, from its clouds to its core. They might even spot changes in volcanoes and their lava flows since Magellan and Venus Express visited.
There could even be more spacecraft joining the party soon — Russia and
India are separately planning their own Venus missions. As Filiberto notes, “Venus might get crowded in the next decade.”