There's a school of thought which views Venus as a better colonization candidate than Mars, and as early as the 70's scientists envisioned floating cities. From https://en.wikipedia.org/wiki/Colonization_of_Venus:
In effect, a balloon full of human-breathable air would sustain itself and extra weight (such as a colony) in midair. At an altitude of 50 kilometres (31 mi) above the Venusian surface, the environment is the most Earth-like in the Solar System beyond Earth itself – a pressure of approximately 1 atm or 1000 hPa and temperatures in the 0 to 50 °C (273 to 323 K; 32 to 122 °F) range. Protection against cosmic radiation would be provided by the atmosphere above, with shielding mass equivalent to Earth's.
Being able to wear a simple breathing mask while working outside instead of a full pressure suit is a boon. Of course high windspeeds and the constant bombardment of acid rain would be a problem.
I could imagine Venus one day being an exotic, cloud-top paradise for the rich (reminiscent of BioShock Infinity) that's expensive to maintain, and Mars a brute workhorse that eventually displaces it as a more resilient habitat over the very long term (eg. after terraforming).
A classic triangle trade ala the sugar, rum, and slave markets in the North Atlantic in the 17-1800s.
Because the nitrox atmosphere we're used to is a lifting gas in the Venusian atmosphere, you could theoretically just fill a big balloon with our atmosphere and live inside it, with lots of Teflon on the outside and suits made of Teflon to work outside the habitat. I also (kind of?) remember reading about using metal nets to capture and condense H2SO4 from the clouds and process it into water, oxygen, and hydrolox rocket fuel.
[0] https://ntrs.nasa.gov/api/citations/20160006329/downloads/20...
https://en.wikipedia.org/wiki/Atmosphere_of_Venus
Lets also not forget the 872F surface temp that will spontaneously ignite anything primarily composed of carbon or the dense sulfuric acid clouds that will destroy most metals in as little as 45 minutes.
We will find life almost everywhere there is an energy gradient, a sufficiently rich substrate, and phase transition boundaries. Life is just a thing that forms in such places.
In our solar system that is Venus, Earth (of course), Mars, Titan (I predict very slow metabolism cryogenic life with a hydrocarbon solvent), and subsurface oceans like Europa if they have a heat source that creates phase boundaries and energy gradients.
It will be mostly simple life though. What we won’t find everywhere is complex life. That took billions of years on Earth. It probably takes a very stable very rich large scale ecosystem with a huge energy flux to cook things like complex multicellularity and cognition, and there are reasons to believe Earth is a rare sort of environment.
https://ntrs.nasa.gov/api/citations/20030022668/downloads/20...
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Imagine living on an airship high above the Earth, with the hard rule that you can never land. You must be entirely self-sufficient save for a tiny amount of material delivered infrequently. Now imagine trying to land on that airship from orbit or get back into orbit (and beyond) from that airship. None of this is easy here on Earth.
A mission that merely orbited Venus and returned without attempting to muck about with airships might be an intermediate step on the way to Mars. Trying to get closer to the surface than orbit would make things a lot harder.
why dont they send a probe to scoop up some venus air and bring it back? seems much easier than going with humans around the moon
"So that’s the bad part. But once you move past it, you start to notice that everything gets easier on Venus."
If wishes were fishes ...
I thought it was resolved as SO2, not phosphine
The atmosphere of Venus in particular is very resource rich, and so it would be incredible to mine it for heavy use by a space economy. This mining is supposed to use free solar power. All of this is a job for robots, not humans.
Being completely tidally locked would be better because near the transition zones the permanent sun would make solar power and plants quite productive.
But an ecosystem where the planet spends most of the year in darkness or dim light?
Basically it's relatively easy to redirect comets to provide gas and liquids for the surface of Mars: that's technically demonstrated technology now.
There's almost no plausible way we could add momentum to Venus to give it a more reasonable day night cycle (I have seen some suggestion that shearing asteroids into it might be possible, but just the magnitude of momentum you're trying to add is staggering).
"In this stifling landscape, there is not likely to be anything alive, even creatures very different from us. Organic and other conceivable biological molecules would simply fall to pieces. But, as an indulgence, let us imagine that intelligent life once evolved on such a planet. Would it then invent science? The development of science on Earth was spurred fundamentally by observations of the regularities of the stars and planets. But Venus is completely cloud-covered. The night is pleasingly long - about 59 Earth days long but nothing of the astronomical universe would be visible if you looked up into the night sky of Venus. Even the Sun would be invisible in the daytime; its light would be scattered and diffused over the whole sky - just as scuba divers see only a uniform enveloping radiance beneath the sea. If a radio telescope were built on Venus, it could detect the Sun, the Earth and other distant objects. If astrophysics developed, the existence of stars could eventually be deduced from the principles of physics, but they would be theoretical constructs only. I sometimes wonder what their reaction would be if intelligent beings on Venus one day learned to fly, to sail in the dense air, to penetrate the mysterious cloud veil 45 kilometers above them and eventually to emerge out the top of the clouds, to look up and for the first time witness that glorious universe of Sun and planets and stars."
. . .
Carl Sagan is an amazing author, and I've shared the famous excerpt from his book Pale Blue Dot multiple times before - https://news.ycombinator.com/item?id=47565381
A few mentions of his books in my blog post here - https://www.rxjourney.net/30-things-i-know
Also, if anything goes wrong on Earth and you're in the atmosphere, there's still a chance you might soar to lower altitudes, eject, parachute, and get rescued. On Venus it's a death sentence.
Well, there's the scenario where a Venusian superbug, having evolved in the roughest possible conditions (temp, acidity, etc...) in the upper Venusian atmosphere, will find Earth's conditions warm, balmy, and altogether ideal to reproduce at 1000x the rate it was constrained to back home :D
"The probe's cargo vessel has a really awesome ablative heat shield on it, as well as some extremely reliable parachutes, and Mission Control is projecting a very soft touchdown in the Utah desert within the next 12 hours. If anyone in the Western United States sees a huge fireball going slower than most meteors, it is probably the Venus Sample Return vessel full of dangerous chemicals! Go VSRM!"
I think that's exactly what the article is arguing for. The part about manned airships is just a whimsical aside to the much safer, entirely feasible, and nearly as scientifically valuable prospect of using unmanned balloons.
Sure, why not?
[0] https://en.wikipedia.org/wiki/Atmospheric_super-rotation
How would that work? Averaged over the planet, you get half the year in darkness and half the year in light. There's no other option.
We have that same ecosystem on Earth.
If you're floating you don't have to track the ground.
Not really scientific books at all. He is popular because he was hyped in the media for being accessible.
Those people dumb down science for the masses - it harms society on the long run imo
I don't believe (could be wrong, not an expert) that spectroscopy is sharp enough to tell you about the structure of complex molecules in Venus's upper atmosphere.
like when in matrix revolutions they climb up above the clouds and see the sun for the first time :')
The advantage of Mars is that it is ( hypothetically ) acceptably compatible with persistent surface-based habitation. Not an easy life, certainly not compared to Earth, but more sustainable than balloons floating in sulphuric clouds.
Venus doesn't offer an 'alternative cradle' option unless we invent anti-gravity. Until then the emphasis will be on finding a way to improve human civilisation's resilience.
Carl Sagan significantly influenced Neil deGrasse Tyson (another popular science writer), for example. But I'm not sure if Tyson would have pursued science regardless of Sagan's influence.
Even though I think you are wrong on this, you seem to be saying it like it's a bad thing ? Why ?
What, exactly, is wrong about inspiring high-schoolers ?
Many physicists have written popular articles and books for the general population. Eg Einstein, Stephen Hawking, Brian Cox. Improving accessibility of advanced concepts is nothing to scoff at.
When explaining something to people outside of science, I was ok with 60% accuracy. Even 50% and some technical lies was fine if this would encourage them to learn more. Some came back to say "you lied!!" and these were one of my most cherished victories.
In lectures for 1st year students, I would have here and there an asterisk with "almost true", to which we would come back a semesters or two later.
Dumbing down science to dumb up people is wonderful.
Your view is just a snobbish and rigid one, Sagan made science topics interesting for more people, from those people very likely many got inspired enough to pursue deeper science training.
Dumbing down is necessary to make it interesting for people who feel it's unapproachable, it breaks a barrier, I have no idea how you look at this and think "this is harming society"...
The difference is in air pressure and gravity.
Gravity means comfort for astronauts. It also makes, I suspect, science and industry a bit easier.
I don’t know what air pressure means. Spacewalks probably get easier. But now your structures have to deal with aerodynamic forces, which is annoying. Making up for that, you’re suspended in a soup of precursors and reagents—that opens up ISRU possibilities. And you should be getting less radiation in atmosphere.
On the whole, if you’re doing planetary science, I think being in the atmosphere is hard to beat. If you’re doing any industry, being near raw materials beats shipping anything unprocessed out of a gravity well. So if you’re staying for a while, you dip in. If, on the other hand, you’re just visiting for a few days, yeah, take a lander and then get back out again.
One reason an expedition to Mars is forever two decades away is because of the leap in difficulty between landing to the Moon and going to Mars.
There’s not a big difference in energy between the two destinations. Any rocket that can land on the moon can easily put a crew in Martian orbit. The issue is time.
As we saw recently with Artemis II, a spaceship can get human cargo to the Moon and back in about ten days. But orbital mechanics makes it hard to complete a trip to Mars in less than two years, and rigid launch windows further constrain options for abort or rescue. Bridging the gap between the two weeks we’ve spent on the Moon and the long, committal journey we’d have to make to Mars runs us into a thicket of difficulties.
In other words, the ladder to the stars is missing some rungs.
It would be nice if there was a class of mission intermediate in difficulty between the Moon and Mars, one that didn’t take us so far out of our experience base and had better abort options than ‘press the red button and wait two years’. Even better if the mission had a milder radiation environment, shorter communications delay, and a high potential for scientific discovery.
This class of mission exists, but no one likes to talk about it:
An orbital trip to Venus is like one of those gorgeous high-rise apartments in Jersey City. Everything about it is perfect except the location.
And I understand the reluctance! Venus is the biggest heartbreak in the Solar System. The planet could have been Earth’s twin, but instead became an acid-washed nightmare and climatological horror story. People have never recovered from the big reveal in the early Space Age that the clouds enveloping our beautiful planetary neighbor covered a hell world.
But with Venus, you have to adopt a ‘glass half full’ approach, even if the thing the glass is half full of is concentrated sulfuric acid.
To get the bad stuff out of the way, the surface temperature on Venus is around 470°C, about as hot as a pizza oven, and the pressure is 92 times what we enjoy here on Earth. The high cloud layers, while temperate, are mostly sulfuric acid. And because volcanic activity has reworked the planet’s surface within the last billion years, there is little hope of finding Mars-like relics of the planet’s habitable past, even if we could build the rovers to look for them. If young Venus had temperate oceans or harbored life, the evidence for it has been buried about as thoroughly as anything in this solar system can be buried.
So that’s the bad part. But once you move past it, you start to notice that everything gets easier on Venus. The atmosphere is great at blocking radiation. Solar panels can be small, and the pressure and temperature in the high clouds are so Earthlike that, if not for the acid, an astronaut could sit in the gondola of a Venusian blimp wearing only an oxygen mask and a swimsuit.
Launch windows to the planet recur every 19 months, compared to 26 months for Mars, and the round trip communications delay is about half of what a Mars-bound crew will face. Abort trajectories still aren’t great, but are about twice as fast as trying to make it home from Mars. And everything goes faster: the orbital mission I cited would get the crew home just three days past the absolute duration record for human spaceflight.
Even the gravity on Venus (0.91g) is homelike, which means that airship habitats, sensors, smoke detectors, toilets, and all the rest can be developed on Earth instead of forcing us to build a space station that can simulate Martian gravity. An entire class of hard problems around physical deconditioning just goes away. Astronauts flying the friendly Venusian skies could recover from the short transit from Earth in a sunny, homelike environment, and if they ever wanted to roast a turkey, they would only have to lower it a few kilometers through the atmosphere on a fishing pole.
There are anomalies in the Venusian atmosphere that are consistent with the presence of life. Unlike on Mars, where any living microbes are presumably deep underground, life on Venus can only exist in the clouds and should be easy to observe (or rule out) with cheap balloons and aerostats.1
Maybe the strongest piece of circumstantial evidence is the detection of phosphine, a gas that has no business being in the atmosphere and should degrade rapidly (within days or weeks) in sunlight. The phosphine detection was controversial when it was first announced in 2022, but it has since been corroborated by multiple measurements. Like the detection of methane on Mars, the pattern of occurrence of the gas remains puzzling.
But the presence of phosphine is just part of a larger pattern of anomalies:
The lower part of the Venusian atmosphere contains an ‘unknown absorber’ that captures about half of the incident ultraviolet light. Its changing large-scale patterns and absorption characteristics are reminiscent of phytoplankton blooms on Earth.
There is an unexpectedly high proportion of water vapor to sulfur dioxide in the high atmosphere. The two gases share a common volcanic origin and should have a similar abundance profile, but SO2 is significantly depleted.
Ammonia exists in the cloud layers, although it should not be possible for it to be there.
There is molecular oxygen in the clouds with no identifiable source.
The clouds at around the 45 km level contain a population of particles called the ‘Mode 3 haze’ . The composition of this haze is unknown, but the particles that comprise it are not spherical, and so cannot be droplets of liquid.
The atmosphere in general is not in chemical equilibrium.
I wrote a few weeks ago that the key constraints for life on Earth are temperature and water activity. For all that the climate in the Venusian clouds is balmy, it’s insanely dry, a hundred times drier than the Atacama Desert. Any life that existed there would have to fight for each molecule of water against sulfuric acid, which is desperately hygroscopic. While complex organic chemistry can exist in acid droplets, it would not resemble anything like the biochemistry we know on Earth.
This is why the detection of ammonia in the otherwise hyperacidic atmosphere is so intriguing. If there’s a mechanism that raises the pH in at least some droplets to around ~1, then Earth-like extremophiles could thrive and be able to photosynthesize in the clouds of Venus2.
Venus researchers Janusz Petkowski and Sara Seager have made an intriguing case that all the anomalies I list can be explained by the presence of microorganisms that produce ammonia from nitrogen and water. The ammonia would react with sulfuric acid to create a kind of slurry, accounting for both the depletion of SO2 and the Mode 3 haze. The pH in such a neutralized droplet would be close to 1, a perfectly livable environment for acidophiles we find on Earth. And a byproduct of their metabolism would be molecular oxygen.
The appeal of this theory is that it’s ridiculously easy to test. Unlike Mars, where we have to delve deep underground to hope to find relic life, we can just go look at the clouds on Venus with a party balloon. The mission is simple enough that Petkowski and Seager are flying a private version of it with RocketLab as a side project, funded by an anonymous benefactor.
The way I like to think about this question is that we can’t lose. Missions to the clouds of Venus are either going to find life or some kind of brand new chemistry, either of which will be a breakthrough discovery in planetary science. There’s basically a guaranteed Nobel prize waiting in the skies of Venus for whoever wants to collect it.
A more sober case for exploring the planet is that we only have three terrestrial worlds to work with. We should learn all we can about how they formed, how they function, and why their fates diverged if we want to better understand exoplanets that humanity won’t be able to physically visit for millennia. Right there is no way to distinguish Earth-like from Venus-like worlds in exoplanet surveys, or even to identify meteorites on Earth that have a Venusian origin. What we learn on Venus will compound our understanding of planets across the sky, not to mention our own planet’s climate.
As a NASA paper points out, humanity has accumulated 31 years of surface time on Mars and 49 years in Martian orbit, but we’ve spent just 4.5 days spent exploring the Venusian atmosphere, and 9.4 hours on the surface. When you consider that every mission to Mars has brought fundamental shifts in our understanding of the solar system, it would be strange if Venus didn’t have surprises waiting for us as well.
There is no planet friendlier to the extraterrestrial balloonist than Venus. Since the gravity, pressure, and temperature in the high atmosphere are all close to Earth, all you need is to apply a little acid protection to your aerostat, and you’re good to go.
And in fact, balloons on Venus were the first aircraft to fly off Earth. Two Soviet Vega probes in 1985 each delivered a French-made helium balloon to the atmosphere. The balloons cruised around at 54 kilometers for about two days before their batteries ran down, covering about 10,000 kilometers in the process.
There are different balloon designs, from easy to hard. The easiest type to fly is a fixed-altitude balloon, which is just a weatherproofed version of the Chinese spy balloon that terrorized America back in 2024. Such a balloon would drift around with the wind and could take advantage of the fact that solar panels in the reflective clouds can point in any direction, with no need to track the Sun.
The next step up from this design is a variable altitude balloon. These balloons use pumps, reservoirs of boiling/condensing water, or just brute force to compress the lifting gas in their envelope, allowing them to vary their altitude by several kilometers. Such a balloon could dip down into the lower cloud layers that are too hot for sustained operations, as well as explore conditions through the full putative habitable zone (45-65 km).
The most ambitious balloon design is a hybrid balloon/flying wing that looks like a B2 bomber that really let itself go. The flying wing would be buoyant, but also sufficiently plane-like to move freely around the atmosphere. The hard part about getting one to Venus is the atmospheric entry. The behemoth would have to serve as its own heat shield, which means it would probably take several practice attempts to stick the initial landing.
And finally, there is the solar-powered airplane. A large enough model could outfly the winds and linger on the sunlit side of the planet for weeks or months. The difficulty here again is delivery. A plane would have to fold up tightly to fit into an aeroshell, and how to get it unfolded and flying in midair is the big technical challenge.
But these are fun problems to have! The science return on any airship design with 2026 sensor technology would be phenomenal, and they could all be rigged to drop a series of sondes or mini-landers down to the surface.
Colorized images of the surface of Venus taken by a Soviet Venera lander in 1981
There are three approaches to handling the problem of heat on the surface of Venus.
The simplest one is denial. You send down a chilled probe wrapped in all the insulation you can manage, and try to arrange a high-bandwidth conversation with an orbiter to maximize the amount of data the lander sends before it cooks. The Soviet Venera landers, the only spacecraft ever to take pictures of the surface, followed this approach. They kept their instruments in near-vacuum inside a titanium sphere and likely survived for several hours after landing (their useful transmission time was limited by line of sight to the orbiter).
A second approach is to put the more sensitive electronics in a refrigerated box. Refrigeration on Venus is a relative term—the cold box on a chilled lander will still be at around 200°C, enough to beautifully roast a chicken. And running a fridge on Venus means having a hot-side radiator at some frightening temperature like 1200°C. But the overall concept is simple: you use electrical power to keep an insulated compartment significantly below ambient temperature, and maybe put in some sapphire windows for the cameras to look through. Such a hybrid design extends the lifetime of a lander from hours to several days or more.
The final and most metal approach is to dispense with refrigeration entirely. NASA has been experimenting with integrated circuits made from silicon carbide that can take a thermal beating. The Glenn research lab has kept chips running at temperatures over 500°C for a year, and even built prototypes that function at 900°C. These electronics are primitive, but more than capable of handling signal processing, amplification, basic imaging, and many of the other tasks you want in a Venus lander. There are even motors strong enough to turn the wheels on a rover. The technology level of this stuff is early 1970’s, but when you consider what kind of data we got from Viking and Voyager, the prospect of doing sustained red-hot science on the surface is thrilling.
Powering a long-duration surface probe is a challenge. Because the surface is so hot and dim, solar panels are impractical. One study estimates solar panels on the surface of Venus would generate about 8 watts per square meter, compared to ~500 watts at an altitude of 60 kilometers, and ~2000 watts in low orbit.3 Industrial batteries exist that work at temperatures near 400°C, but there is still some work to be done to get them functioning at the ambient temperatures on Venus. Nuclear RTGs could work, but have to run extremely hot.
On the plus side, because the atmosphere at ground level is thick, a small wind turbine might be enough to keep a battery topped up indefinitely. As long as we can live with low data rates, a next-generation lander could stay alive on the surface for several months.