Why NASA Is Finally Returning to Venus After 40

Here's something that should bother you: the United States hasn't sent a dedicated mission to Venus since the 1980s. Not the '90s. Not the early 2000s. The 1980s—when we were still using floppy disks and arguing about whether compact discs would catch on.

Venus. Our literal sister planet. Roughly the same size as Earth, same surface gravity, sitting right next door in cosmic terms. And we just... stopped looking at it.

David Grinspoon finds this as baffling as I do. He's a planetary astrobiologist at Georgetown University, on the science team for NASA's upcoming DAVINCI mission, and he literally wrote the book on Venus—Venus Revealed, published right after that last US mission in the '80s. On a recent StarTalk episode with Neil deGrasse Tyson, Grinspoon walked through why we abandoned Venus, what changed, and what we might find when we finally go back.

The story turns out to be less about Venus itself and more about us—our dreams, our propaganda, and our remarkably persistent habit of projecting what we want to see onto blank cosmic canvases.

The Cloud Swamp Dream

For most of the 20th century, scientists assumed Venus was probably pretty Earthlike. The reasoning was straightforward to the point of being charming: Venus is covered in clouds. Clouds are made of water. Therefore, Venus must be a water world—possibly a swamp planet, lush and humid and teeming with life.

"Throughout the whole time of really the 20th century up until the space age, there was a lot of speculation that Venus was probably pretty Earthlike," Grinspoon explained. "A lot of scientists thought that and could have life."

This wasn't fringe thinking. This was the working assumption. And it fit perfectly into a broader pattern: before we knew much about the solar system, the default position was that all planets probably had life. We had life, we were a planet, ergo every planet should have inhabitants. It's almost sweet how optimistic that is—and how wrong.

The illusion started cracking in the 1950s when radio astronomers detected excess microwave radiation from Venus that didn't make sense. Could it be coming from a superhot surface? But the real death blow came in 1961 with Mariner 2, the first successful planetary flyby mission. Venus wasn't a swamp. It was hell.

Surface temperatures hot enough to melt lead. Atmospheric pressure 100 times that of Earth—the equivalent of being 3,000 feet underwater. A runaway greenhouse effect that turned our sister planet into a demonstration of what happens when a climate feedback loop goes catastrophically wrong. Not exactly prime real estate.

And so, for decades, we largely lost interest. Mars became the sexy target. Europa, Titan, the outer solar system—all more appealing than studying a planet that seemed to offer nothing but a cautionary tale.

What Changed

Two things brought Venus back into focus, and they're both relatively recent. The first is the phosphine controversy—the 2020 announcement of potential biosignatures in Venus's cloud deck, which sparked immediate scientific debate about whether the detection was real and what it might mean. (The jury is still very much out on that one, and Grinspoon is appropriately cautious about it.)

The second is broader: we've gotten better at asking different questions. Instead of "Is there life on Venus's surface?" (no), scientists are now asking "Could life exist in Venus's atmosphere?"—a question that would have seemed absurd a generation ago but now fits into a larger framework of thinking about habitability.

"How much credence is given to the idea that life could be completely thriving within an atmosphere and not require a surface at all?" Tyson asked.

"We have to keep an open mind about that," Grinspoon said.

It's a genuine possibility, not just speculation. We find life in the most implausible places on Earth—in boiling acidic springs, in Antarctic ice, in the driest deserts. Why not in a permanent cloud deck where conditions might be relatively mild compared to the inferno below?

DAVINCI and VERITAS: The Return

NASA is sending two missions to Venus in the 2030s. VERITAS is an orbiter that will map the surface with unprecedented resolution. DAVINCI—the mission Grinspoon is working on—is a descent probe that will drop through Venus's atmosphere, taking measurements and capturing the first 21st-century photographs of the surface on the way down.

"We're going to reach the surface," Grinspoon said, carefully avoiding the word "crash"—a semantic choice that planetary scientists apparently care about.

The engineering challenges are spectacular. How do you build something that can survive pressures 100 times Earth's and temperatures that would turn you into a pizza topping? The Soviet Union managed it with their Venera landers in the 1970s and '80s—some of which survived on the surface for over an hour, sending back the only photographs we have of Venus's ground. But that was half a century ago with Soviet technology. What can we learn now with modern instruments?

Grinspoon pointed out something that struck me: throughout all of human history, we've sent exactly one US mission to Venus with modern scientific instruments—Magellan in 1989, which gave us radar maps but no atmospheric data. "Since the 1980s, we have not had a US mission to Venus," he said. "We're trying to change that now."

The Ingredients Are Everywhere

Here's where the Venus story connects to the broader question Grinspoon's Georgetown [course explores: what does our vision of space tell us about ourselves?

The episode touched on the OSIRIS-REx sample from asteroid Bennu, which revealed 14 different amino acids. The Europa Clipper is heading to Jupiter's icy moon. The ingredients for life—carbon, water, organic molecules—keep showing up everywhere we look. "The kit for life seems to be sprinkled across the cosmos," Tyson noted.

If the ingredients are common, could life itself be common?

Grinspoon's course at Georgetown—"Justifying Space: A History of Space Futures"—examines how the dreams that drove space exploration have always been reflections of contemporary culture and politics. Wernher von Braun and Walt Disney creating propaganda films in the 1950s about humanity's glorious future in space (while carefully omitting mentions of aliens). The Collier's magazine illustrations by Chesley Bonestell that helped Americans imagine what space stations and moon bases would look like. The Apollo program as a geopolitical flex during the Cold War.

"It's not quite just asking what happened," Grinspoon explained. "It's what were people thinking? What was the motivating vision? What future did they think they were creating?"

We're still doing this, of course. Every space mission carries implicit assumptions about what matters, what's worth investigating, what kind of future we're building toward. Venus fell out of favor not because it became less interesting, but because the story we were telling ourselves about space—exploration, colonization, finding new homes—didn't have room for a planet that would kill you instantly.

But maybe the question isn't whether Venus can host human colonies. Maybe it's whether Venus can teach us something about how planetary atmospheres evolve, how greenhouse effects spiral out of control, and whether life is creative enough to find a niche in conditions we'd consider impossible.

"We don't use that word," Grinspoon said about crashing. "We're going to reach the surface."

Semantic precision matters when you're trying to land a probe on a planet that's been waiting 40 years for us to come back and take it seriously. DAVINCI launches in 2031. I'll be watching to see what Venus reveals this time—and what it reveals about us.

—Nadia Marchetti, Unexplained Phenomena Correspondent