Last time I talked about how successful human colonies would likely need to begin with an existing culture. This time I’d like to talk about one of the places that humans might wish to colonize, and it is the first post in a series about Venus that I have wanted to write for a long time. What would it take to make the surface Earth-like, what would it take to live there before we make it Earth-like? I think Venus deserves more attention than it gets for three simple reasons, gravity, pressure, and temperature.
The series will get to the terraforming engineering eventually, including things like energy budgets, propulsion problems, orbital mechanics, parasols and solettas and electromagnetic spin-up motors. All of that good stuff eventually. But first I want to talk about where humans can actually live, right now, with the engineering capabilities we have or could plausibly develop in the next century.
That place is Venus. Not the hellish surface of course—which is at a temperature of 737K/464C/867F under 95 bars of carbon dioxide—but the cloud layer, at 50 km altitude.
This was an extremely fringe view for a long time, but less and less as people seriously think about it. NASA Langley spent two years on the High Altitude Venus Operational Concept (HAVOC), a phased mission architecture built around floating habitats. Geoffrey Landis published the modern technical case in a 2003 NASA paper that is still the canonical reference. The Soviets were working on atmospheric Venus habitation concepts in the 1970s. Paul Birch’s 1991 paper, which we will spend several posts on later in this series, treats floating colonies as the primary human habitat throughout the centuries-long terraforming process. The case has been in the literature for half a century. The popular conversation just has not caught up to it, so let’s plunge in.
The 50 km altitude
Venus’s atmosphere falls off exponentially with altitude. The scale height depends on local temperature, varying from about 16 km at the surface (where T = 737 K) to about 6 km at the cloud deck (where T ≈ 290 K). The 95 bar surface pressure drops by a factor of about 95 over the first 50 km of altitude, working out to a column-averaged scale height of around 11 km. At 50 km altitude you reach 1 bar of pressure, which is almost exactly Earth sea level, and temperatures between 0 and 50 degrees Celsius depending on local time and latitude. Climb another 5 km and the temperature drops into the 20s. A spring day, in other words.
Gravity at this altitude is essentially Venus’s surface gravity, 8.87 m/s², or 0.904 g. That is meaningfully lower than Earth gravity — about 10% less, which is much larger than the 0.5% variation humans experience between the equator and the poles, or between sea level and the top of Everest. We do not know exactly what 0.904 g does to the human body over decades and generations, because we have no data points between 1 g and zero. But the deficit is small. Mars at 0.379 g and the Moon at 0.166 g are dramatically further from Earth gravity than Venus is. If there exists a habitable gravity range for long-term human life with some lower bound, Venus’s 0.904 g is almost certainly inside it, and Mars and the Moon are almost certainly outside it.
The atmosphere above 50 km provides about 1 kg per square centimeter of mass shielding against cosmic radiation, which is approximately the same column density as Earth’s atmosphere. Dale Arney and Chris Jones, in the HAVOC study, put it bluntly: radiation exposure at the 50 km altitude on Venus is about the same as you would experience in Canada. Call it 0.01 mSv per day above Earth-surface background. Comparable to a high-altitude airline pilot.
Compare those numbers to the alternatives:
Mars surface: 0.64 to 0.7 mSv per day, measured directly by the Curiosity rover’s RAD instrument. About 230 mSv per year.
Lunar surface: roughly 0.4 mSv per day. No atmospheric shielding at all. Habitats require buried construction or regolith berms or water tanks for radiation protection.
Free space, International Space Station, O’Neill habitat: 0.4 to 1.0 mSv per day depending on the solar cycle.
Mars transit: 1.8 mSv per day for the duration of the cruise.
Venus 50 km altitude: approximately equivalent to Earth’s surface.
The cloud layer of Venus is, in radiation terms, the most Earth-like environment in the solar system outside Earth itself. By a factor of 50 to 100 over the Martian surface. By larger factors over the Moon or free space.
That single fact is almost enough to make the case. But there is more.
Your air is your envelope
Here is the design feature that makes everything else work. The first time you hear it, it sounds like science fiction. It turns out to be elementary atmospheric chemistry.
Venus’s atmosphere is 96.5% carbon dioxide. The molar mass of CO₂ is 44 grams per mole. A breathable nitrogen-oxygen mix — 78% N₂ at 28 grams per mole, 21% O₂ at 32 grams per mole — has an average molar mass of about 29 grams per mole. Gas density scales linearly with molar mass at the same temperature and pressure, so breathable air is about two-thirds the density of the surrounding Venusian atmosphere. The buoyant lift is the difference, about 0.63 kg per cubic meter at cloud-deck conditions.
That means breathable air is a lifting gas on Venus. About 0.6 kilograms of lift per cubic meter, which is around 60% of what helium gives you on Earth.
Think about what this means. On Earth, a balloon requires helium or hot air — something different from the surrounding atmosphere. You have to manufacture or import the lifting gas, contain it in a sealed envelope, and keep it separate from the air your passengers breathe. On Venus, the air your colonists breathe is itself the lifting gas. There is no separate lift envelope. There is no pressure differential to maintain. The inside of your habitat is 1 bar of N₂/O₂, the outside is 1 bar of CO₂, and the structure sits in mechanical equilibrium.
This is the dream of every pressure-vessel engineer. Pressure vessels are hard! They want to burst. They fatigue under thermal cycling. They require thick walls, leak monitoring, double-hull architectures. Every other off-Earth habitat anyone has proposed — Mars surface, lunar surface, O’Neill cylinder, space station — is a pressure vessel holding 1 bar against vacuum. A Venus cloud city is not a pressure vessel at all. It is a containment envelope at zero pressure differential. The walls only need to keep the two atmospheres from mixing across the boundary. They do not need to contain pressure.
The structural mass implications are staggering. Birch estimated his floating colonies at 1000 kg per square meter total areal density, with 200 kg/m² for the base structure and 50 kg/m² for the roof. The rest is soil, water, agriculture, and habitation. By comparison, an O’Neill cylinder requires meters of bulk shielding, plus a pressure-rated hull, plus structural accommodation for rotational stress, and even the lightest designs are orders of magnitude heavier per unit habitable area.
Versus Mars
Mars is the obvious comparison.
Where Mars wins: Mars has water ice in known accessible quantities. Mars has a 24.6-hour day, well within human circadian tolerance. Mars has surface chemistry — Sabatier reactions, perchlorate processing — that produces oxygen and propellant from in-situ resources. Mars is energetically cheap to reach from Earth, with delta-V budgets we know how to handle. Rovers have been operating on the surface for decades and we have a deep operational understanding of the environment.
These are real advantages.
But here is what you trade for those advantages: surface gravity of 0.379 g, which we have no biological evidence is safe for long-term human habitation; atmospheric pressure of 0.006 bar, which means full pressure suits required any time anyone steps outside; mean surface temperature of −63 °C, with excursions to −140 °C at the poles; radiation exposure 50 to 100 times higher than at Earth’s surface; solar power density at 590 W/m² compared to Earth’s 1361 and Venus’s 2620; and global dust storms that bury solar panels and grind into every seal and joint in your equipment.
The dust point is underappreciated. Martian regolith is electrostatically charged, mildly toxic from perchlorates, and gets into everything. Apollo astronauts complained about lunar dust within days of their first surface operations. Mars colonists will be dealing with dust intrusion problems for decades, in habitats, in equipment, in their lungs. Venus cloud habitats face sulfuric acid, which is corrosive but contained. Acid is a chemical engineering problem. Dust is a mechanical infiltration problem. The first is easier.
What about day length? Venus rotates once every 243 days retrograde — pathologically slow, and we will spend three posts on that problem later in this series. But at the cloud altitude, the super-rotating atmosphere circles the planet much faster than the surface. A floating colony drifting with the cloud layer experiences a solar day of about 4 Earth days at the equator. Not 24 hours. But not 117 days either, which is what surface settlements would face. And cloud cities can choose their drift rate to some extent by altitude selection. Mars wins on day length. But the gap is much smaller than people usually assume.
Mars has water and propellant and a Sun-friendly day. Venus cloud altitude has nearly every other habitability advantage that matters for human bodies and human structures. We have been investing in the harder planet.
Versus the Moon
The Moon is the closest body and the cheapest in delta-V. Three-day transit each way. No atmosphere to complicate landing. Known ice deposits in permanently shadowed polar craters. Working ISRU concepts for regolith oxygen extraction.
The Moon makes sense as an industrial outpost, a science platform, a stepping stone for cislunar infrastructure. It does not make sense as a place where humans live for generations.
Lunar gravity is 0.166 g. That is even further from Earth gravity than Mars is — about 44% of Martian gravity. Whatever speciation pressure 0.379 g produces on Mars, 0.166 g produces faster and more severely on the Moon. The lunar surface is a vacuum environment with temperature swings of 300 °C across the 14-day lunar day. Radiation exposure is in free-space range, with no atmospheric shielding at all. Habitats have to be buried under regolith, built underground, or shielded with water tanks. The whole architecture is constrained by these requirements.
A lunar base is a good idea. A lunar civilization, in the sense of millions of people living their lives there for generations, is a more troubling proposal. The biology does not work, and we have not been honest about that.
Versus O’Neill cylinders
The free-space habitat advocates — Gerard O’Neill’s intellectual descendants in the National Space Society and adjacent groups — have a real case I want to take seriously. O’Neill habitats can be built anywhere there is solar power and raw material. They can be sized for any population. They can rotate to provide any artificial gravity, including exactly 1 g, which puts them in a different biological category from Mars or Moon surfaces. They scale with industrial capacity in ways that planetary surfaces do not.
The problem is the construction cost.
A Stanford torus or Bernal sphere is millions to tens of millions of tonnes of structure. The radiation shielding alone is meters of bulk regolith or water, which is kilotonnes to megatonnes of mass per habitat. The pressure containment is a serious materials problem. The rotational stability and station-keeping require active control. Every single habitat has to be built before anyone can move in. There is no incremental occupation of a half-finished O’Neill colony.
Compare that to a Venus cloud habitat, which can be a single inflated structure deployed from a single lander mission, lifted by the breathable air inside it. Birch’s floating colonies at 1000 kg/m² scale linearly with envelope area. A square-kilometer colony at one million kilograms is comparable in mass to the International Space Station and hosts hundreds of people. Scaling up means inflating more envelope.
O’Neill cylinders are more flexible. You can put them anywhere, size them however you want, give them whatever rotational gravity you choose. Venus cloud cities are more immediate. They can be built with substantially less industrial infrastructure than a free-space colony requires. For the early decades and centuries of off-Earth settlement, cloud cities arrive first.
There is also a deeper distinction. An O’Neill cylinder is a constructed environment. Every cubic meter of air, every kilogram of water, every photon of light is provided by engineering. A Venus cloud city sits inside an environment. The air outside is at breathing pressure (if not breathable composition), the temperature is shirt-sleeve, the gravity is set by the planet. The cloud city is the more forgiving habitat. A pressure leak in an O’Neill cylinder is a hull breach. A pressure leak in a Venus cloud city is a slow exchange between two atmospheres at the same pressure. The failure modes are categorically different.
What a cloud city actually looks like
Let me describe a plausible early Venus cloud habitat, drawing on Birch, Landis, and HAVOC.
You arrive in Venus orbit and aerocapture into an entry trajectory aimed at the equatorial day side. Your habitat is packed inside an aeroshell similar in scale to a Mars EDL system — a few tonnes of payload behind a heat shield. At about 70 km altitude you deploy a parachute. At 60 km you jettison the aeroshell and begin inflating the habitat envelope. The same envelope serves as parachute (during inflation) and as the buoyant structure once full. By 55 km altitude the envelope is inflated and your lift is sufficient to halt descent.
You float at 50 to 55 km altitude in equilibrium with the surrounding atmosphere. The envelope is filled with breathable air at 1 bar — the same pressure as outside but about half the density. Your habitat hangs below the envelope, or is integrated into it, shielded from cloud-layer sulfuric acid by an outer skin of fluoropolymer or coated polymer. Your structure is light because there is no pressure differential to contain. Your radiation environment is Earth-equivalent. Your gravity is 0.904 g. Your power comes from solar panels on the upper envelope surface, which receive nearly twice the irradiance of an Earth-surface panel plus significant reflected light from the cloud layer below.
You move horizontally by riding the super-rotation winds, about 95 m/s eastward at cloud tops, slower below. You move vertically by adjusting envelope volume through compression or venting. The super-rotation is a feature, not a problem. It gives you a 4-day day-night cycle and continuously carries you across the planet, exposing you to varying weather and giving you global access without translational propulsion.
You grow food in pressurized greenhouses or in the main envelope itself, since the air is already there. You collect water from cloud humidity or extract it from sulfuric acid, which is, after all, mostly water by molar count. You scrub CO₂ leakage and replenish O₂ through electrolysis or photosynthesis. You communicate with Earth through a relay satellite in Venus orbit, with round-trip light times of 4 to 28 minutes depending on planetary geometry.
This is mission-architecture-compatible with present technology. The HAVOC study laid out a phased approach — robotic precursors, then short-duration crewed flybys, then longer crewed stays in orbit, then atmospheric habitats — using technology that is at TRL 5 or higher today. The hardest unsolved problems are sulfuric acid resistance for long-duration envelope materials, large-scale envelope deployment, and propulsive return from the atmosphere to orbit. None of these requires breakthrough physics. All of them are tractable engineering.
Why this is not the dominant proposal
Why does Mars dominate the human-spaceflight conversation rather than Venus? Several reasons.
First, cultural inertia. Venus became unfashionable after Mariner 2 confirmed the surface temperature in 1962. The popular space-advocacy community moved its attention to Mars and never came back. The cloud city case requires explaining a counterintuitive idea — that you can live in a planet’s atmosphere without being on its surface — which is a conceptual move that surface-bound Mars colonization does not require. Familiar wins over unfamiliar.
Second, surface bias. “Colonize Venus” sounds, to most people, like “colonize the Venusian surface,” which is obviously preposterous given that the surface is 737 K. The cloud city case requires a conceptual move that popular discussions do not make. Mars surface settlement is at least visualizable. Venus cloud settlement requires explanation.
Third, economic geography. Mars has been pitched as a stepping stone outward to the asteroid belt, the outer planets, eventually the stars. Venus is on the inside of Earth’s orbit and leads outward only to Mercury and the Sun. For a settlement strategy organized around outward expansion, Mars is in the right place geographically and Venus is not.
Fourth, ISRU. Mars has accessible water ice, mineral resources, and surface materials usable for construction. Venus has none of those in easily extractable form. Atmospheric mining is harder than regolith mining, and the surface is inaccessible. For mission concepts emphasizing in-situ resource utilization, Mars has the obvious edge.
Fifth, robotic exploration. We have continuous robotic presence on Mars and have for decades. Our intuitions about Mars are rich and our institutional momentum on Mars exploration is enormous. Venus has been visited briefly by Soviet landers (lasting about two hours each) and by atmospheric probes. The robotic exploration gap reinforces the cultural and political gap.
These are real reasons. They are not, however, engineering reasons. They are reasons about which planet we are familiar with, which planet fits an outward-expansion narrative, and which planet has better local resources for an isolated outpost. None of them are reasons that the habitats themselves would be harder to build on Venus than on Mars.
The engineering case is straightforward. Venus has a layer where humans can live in shirt sleeves at 1 g with Earth-equivalent radiation shielding. Mars does not. The Moon does not. Free space does not. The settlement strategy that takes biology seriously settles where biology wants to live.
What this means
Venus is the easiest place humans can live off Earth. Not the easiest place to land. Not the easiest place to extract resources. Not the easiest place to reach. But the easiest place where, once you have a habitat in place, humans actually live in a way that does not constantly fight their biology and their engineering.
Habitability is not a surface property. Earth’s surface is not habitable for most of life that we care about. Most of Earth’s biosphere lives in oceans, not on land. Our own habitable zone is a thin layer at the bottom of an atmosphere. The lesson of Venus is that habitability is about finding the right layer in a planetary system, not about finding the right planet.
That lesson generalizes. Jupiter has a 1-bar layer. So does Saturn, Uranus, Neptune. The radiation environments at most gas giants are hostile, especially Jupiter’s, but the atmospheric pressure and temperature of the right layer of any gas giant is closer to Earth-like than the surface of any rocky world except Venus and possibly an early-period Mars. Cloud-layer habitation may be the normal way humans will eventually live on most worlds in the solar system. Rocky-surface settlement of the Earth kind may turn out to be the exception, obtaining only on the small minority of bodies where the geology cooperates.
That is a different vision of human expansion than the one we have inherited. I think it is the one the engineering favors.
The next post in this series will make the case that beginning a serious cloud-city presence on Venus makes terraforming the surface inevitable. Not as an aspiration. As a consequence of biology, economics, and what people want from a planet they have committed to live on. The argument turns on something I have come to think is the deepest constraint on off-world human settlement, which has nothing to do with engineering and everything to do with what we are.
I hope these thoughts help you see why Venus deserves more serious attention than it has been getting, and why the conversation we have been having about Mars for the last forty years has been, in important ways, the wrong conversation.
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I am not sure I understand one aspect of scale height mentioned in the early article. From 95 atmospheres at the surface to 1 atmosphere would seem to be between 6 and 7 scale heights, which 50 km would divide into scale height being around 8 km. You say that the scale height is 16 km which would put the habitable layer at around 100 km.
Also that CO2 at 44 is somewhat less than double breathable at 28. More like 2/3 if I understand correctly.
These are nitpicks that may be more my understanding than real and do not detract from the meat in the article. I am interested in the economic case in upcoming articles, as that is my primary concern about Mars colonization as well.
Very good catch, John. I’ve applied corrections to the original post to address the points you’ve made. Keep up the good work!
Kirk,
Always good to see articles about Venus cloud settlements. I started a series on the topic, including looking at some ISRU aspects probably about 10yrs ago (see the Venus category on the blog), but never got around to finishing it. One of the biggest challenges I had was coming up with a credible (to me) solution for fully-reusable round-trip rocket transportation from orbit to the cloud colony and back. There are ways to do it expendably, but ideally you want a reusable solution that has a high probability of working, and graceful and survivable abort modes. If we can solve and convey that piece, I think people will take Venus settlement more seriously. I’m looking forward to the rest of what you’re planning to write on the topic!
~Jon
Another nice property of everything being at ambient pressure: the colony is repairable and maintainable.
Have an H2SO4 corrosion spot? Just replace it, with a temporary barrier to keep the nasty air out. Same thing for planned maintenance.
An interesting question is whether you can expand a colony this way. Presumably, you’re adding lots of weight without buoyancy before you make things marginally airtight and can reduce the density. But you can deploy a nitrox balloon inside the addition, then build over it.
Another advantage over Mars: better orbital mechanics:
1) Shorter synodic period, with (I think) wider departure windows.
2) Shorter times of flight from/to Earth. Using a dumb, circular, in-plane model, I can get a v4 Starship-sized vehicle from Earth to Venus in about 2 months, with enough extra delta-v to scrub off the arrival v∞ down to 11km/s.
3) Higher allowable entry speeds. Mars is limited to about 7.8km/s, because of the amount of negative lift you need to keep the vehicle in the atmosphere. Venus is pretty much Earth-sized, so it can use Earth-sized entry speeds of about 11km/s. Weasel words: It’s a CO2 atmosphere so you still need to deal with the free oxygen problem, same as Mars. That may reduce the entry speed a bit.
Better logistics goes a long way to mitigate the inability to do immediate ISRU for metals and trace elements.
“””One of the biggest challenges I had was coming up with a credible solution for fully-reusable round-trip rocket transportation from orbit to the cloud colony and back. There are ways to do it expendably, but ideally you want a reusable solution that has a high probability of working, and graceful and survivable abort modes. If we can solve and convey that piece, I think people will take Venus settlement more seriously. “””
This bothers me too.
On Earth, a SSTO has to go from zero speed, solid ground; to orbital velocity (7.8 km/s) – except it is 9.3 km/s with all three ascent losses – gravity, drag, steering.
On Venus a SSTO has to go from “floating cloud city 50 km high” to orbital velocity. How much delta-v is that ?
1-Venus is 10% smaller and also lighter and less dense than Earth; so its orbital velocity must be less than 7.8 km/s (is it less than 7 km/s ?)
2-What about the three ascent losses ? gravity, drag, steering ? How much do they add to the tally, on Venus ?
3-Thinking about it, a rocket dropped from a Venus floating city is akin to a Zeppelin dropping a rocket on Earth; kind of air-launch, which often helps a little with the delta-v. See below: 600 m/s ?
[I have on my HD a tech paper about air-launch from Purdue University which says
“A study by Marti Sarigul-Klijn et al. concluded that at an altitude of 15250m, a rocket launch with the carrier vehicle having a zero launch velocity at an angle of attack of 0° to the horizontal experienced a Δv benefit of approximately *600m/s* The zero launch velocity situations can be used to represent the launch from a balloon as it has no horizontal velocity.”]
Drats, forgot something. Quick Internet search says Venus escape velocity (from its surface) is 10.4 km/s. On Earth, it is 11.2 km/s. Make sense, Venus is a touch easier to escape because it is a touch smaller than Earth.
The ratio between the two escape velocities is 89% – and if applied to Earth 7.8 km/s, that’s a 6.96 km/s orbital velocity for Venus.
With all three losses: 9.3 km/s by 89% is 8.277, let’s round that to 8.3 km/s.
Total WAGs of course ! But those small delta-v “bonus” for Venus should help a local SSTO, albeit not by much. Probably a few percents of mass fraction shaved of an hydrolox SSTO (needs 0.89 on Earth as a bare minimum).
@Archibald:
Using vis-viva, I get 7209m/s as orbital speed for a 200km x 200km low Venus orbit.
I suspect the short answer is that SSTOs for Venus have pretty much all the disadvantages of SSTOs for Earth, for the same reasons. If you’re launching from a 1bar location, atmospheric drag will be roughly the same, mod slight differences in scale height. Similarly, gravity drag will be roughly the same, mod slight differences in local gravitational acceleration.
That brings up an interesting question: Suppose you wanted to use an existing launcher on Venus? How would you get the lower stages there? For example, if you wanted to use Starship, you’d need to get a small fleet of SuperHeavies to your cloud colony. Is there a way to do that?
Even though SuperHeavy has less delta-v available than a Starship, even when it’s only moving itself, it has enough to depart LEO and propulsively enter a low Venus orbit. So with refueling gear added to a SuperHeavy, it should be possible to do the following:
1) Launch the SuperHeavy to LEO on its own. (Requires a nosecone; shouldn’t be a big deal.)
2) Refuel it.
3) Depart LEO for a near-Hohmann transfer to Venus.
4) Using remaining prop in the SuperHeavy (requires prop boiloff management!), propulsively brake into an LVO (low Venus orbit). By my calculations, there’s enough prop in a v4 SuperHeavy to do this, if it’s completely full at LEO departure.
5) Completely refuel the SuperHeavy, using depots pre-positioned in LVO.
6) Now comes the fun part: We need to execute a deorbit burn that reduces the SuperHeavy’s speed to about 5300m/s at entry interface, to make its current thermal protection adequate to complete the rest of the “landing”. The problem here isn’t the delta-v budget, which is more than adequate. However, burn time is crucial. If you’re in an orbit with a viable periapsis and you deorbit, you’ll drop the periapsis well below the surface of the planet to get to the target speed, and your SuperHeavy will drop like a stone. The trick is to figure out how to expend enough delta-v quickly enough that speed reduction happens faster than the time it takes the SuperHeavy to lose the altitude from LVO to entry interface. I think this is doable, but it’s a computation beyond my capabilities to perform.
7) After this, you basically have a regular SuperHeavy RTLS. Enter, kill off the 5000m/s of speed, then fire the engines to land on chopsticks attached to the cloud colony.
8 ) To launch Starships back to Earth, fill up the SuperHeavy, using your cloud colony ISRU water distillation / electrolysis / Sabatier plant, and do an ordinary SuperHeavy / Starship launch. SuperHeavy will do a regular RTLS.
This requires an almost unimaginable amount of prop to orbit to pull off, but it gets amortized over the life of the SuperHeavy. And it means that you don’t have to manufacture first stages on Venus.
This recent article may be pertinent:
https://aviationweek.com/space/space-exploration/spacexs-mars-mission-based-unproven-dangerous-premise
Dropping a large mass, like a rocket, from a floating habitat would have an adverse effect on the floating habitat. As soon as it lost the mass, it would rise suddenly, maybe catastrophically. The rapidly rising floating habitat would obtain an immediate and increasing positive pressure, and might rupture. This is not a problem, if the habitat is considered disposable; but for a permanent colony, this would be an engineering challenge to be solved.
I don’t think that the length of the day on other celestial bodies will affect the ability of humans to live there. For biological reasons, they will have to follow Earth-like 24-hour cycles of sleep and waking regardless of local conditions.
Therefore, they will rely on artificial lighting to regulate life inside their habitats and will only use natural daylight as a supplement when it is available at the right times. There would probably be psychological benefits in regular exposure to natural light, and it would reduce the amount of power required for artificial lighting over the course of the local day-night cycle.
However, the length of the local day does determine how much of the time a settlement can rely on solar power. This in turn determines what energy storage capacity and/or alternative power sources it will need to survive the night.
A free-space habitat can be placed in an orbit where solar power is always available. A habitat on the Moon or Mars could use local resources to generate power through chemical processes. It would also be surrounded by empty land on which large, heavy, or hazardous, machinery could be installed, including nuclear reactors shipped from Earth.
But a floating Venus habitat would have few or no local resources to exploit, and would have much more limited space and carrying capacity than a surface settlement. Therefore, it would need to rely on solar power as much as possible. Backup systems would have to be kept to a minimum, and it would need to float at an altitude where its local day-night cycle didn’t last more than a few Earth days.
This means that the work/leisure cycle for the inhabitants would be determined by the availability of solar power. The local day would form the “working week”, when there was enough power to run all the onboard systems, and the local night would be the “weekend” with many non-essential systems shut down.
So, for a cloud settlement with a solar day of about 4 Earth days, that might mean 2 Earth days of work followed by 2 Earth days of rest, or maybe 3 and 1 if the habitat has sufficient energy storage capacity to continue normal work into the dark period. In the long term, this pattern might well survive as a cultural norm long after technological advances had rendered it unnecessary.
“Dropping a large mass, like a rocket, from a floating habitat would have an adverse effect on the floating habitat. As soon as it lost the mass, it would rise suddenly, maybe catastrophically.”
I was thinking about putting a pipelauncher into the Venus atmosphere.
A pipelauncher is something like a spar buoy.
“A spar buoy is a tall, thin buoy that floats upright in the water and is characterized by a small water plane area and a large mass. ”
https://en.wikipedia.org/wiki/Spar_buoy
So was going use a pipelauncher launch from Earth’s ocean to put something like a pipelauncher in Venus atmosphere.
So a pipelauncher, launches rockets, and pipelauncher could catch a rocket.
But it is mainly about an assisted launch and getting rocket going to around 100 mph.
So, for Venus pipelauncher to get off Earth, it needs rockets, and was thinking of using quite a few of small rockets to do this.
Or I was thinking of using Minotaur IV rockets which use solid fuel rockets:
https://en.wikipedia.org/wiki/Minotaur_IV
–Height 23.88 m (78.3 ft)
Diameter 2.34 m (7 ft 8 in)
Mass 86,300 kg (190,300 lb)
Stages 4 —
But it seems one launch these small rockets attached on the sides of Venus pipelauncher. And the launch from the Earth pipelauncher would assist the Minotaur rocket get payload to orbit, but also have Minotaur use their rocket power to get the Venus pipelauncher to Earth orbit. So one might have 3 Minotaur get twice their normal payload [or more] to orbit, and 3 another Minotaurs not delivering any payload to orbit, or just using the rocket power lift the Venus pipelauncher to orbit.
Similarly, one could drop rockets from a Venus airship, and then they fire engines go somewhere. And that lost weight make Venus airship go up with some velocity, and then one use that upward velocity to launch another rocket to orbit.
So, what I call a pipelauncher, is a spar buoy, a cylinder or something which is tall and narrow diameter, such as 100 meters tall and 10 meters wide. And one might not think 10 meters isn’t narrow, but RP FLIP, the largest spar buoy is roughly those dimensions,
and in terms of pipelauncher used on Earth to lift the Venus “pipelauncher” could have dimension of 24 meter diameters and 400 meter tall- and because it’s tall, 24 meters in diameter is narrow, and it floats vertical stable in the ocean, and it’s 24 meter diameter wall thickness could be about 1 cm thick of marine alloy. And it would be what I call a multistage pipelauncher and is also a zero stage for the Venus pipelauncher,
And Venus pipelauncher is quite a bit bigger, with it’s pipe walls made of strongest titanium alloy [about 3 times stronger than the marine aluminum alloy] and it would have thinner wall, 2 mm or less thick, and could also use inflatable balloons [mostly on for a temporary use- so deploy them and then later stow them],
Now to get to Earth orbit, one will use rockets, and one accelerate the venus pipelauncher at about 1/2 gee acceleration until one is about 10 km high, starting with Earth pipelauncher, and expending rocket stages to get around 10 km- and they wouldn’t be going very fast, and one could fairly easily recover and re-use these rockets. And some of rocket could then add some velocity to the Venus pipelauncher, then separate from it, and go orbit [perhaps with most payload then compared to launching from the ground.
So, Earth and Venus pipelauncher are spar buoys and they launch and can recovery or have rockets, land on them. And both point constantly to the center of gravity- though one could also rotate them in space for artificial gravity uses.
“A single rotation on Venus’s axis takes 243 Earth days, making it the longest rotation of any planet in the solar system.”
So, on Venus rocky surface, there are very long days and nights, but if living in the Venus sky, it said the days are about 4 to 5 Earth days. So Venus has fast moving winds and wind speed vary- particularly in regards to different elevations.
So to travel in Venus atmosphere one should go with the wind, and if going up and down in the atmosphere, one could control the speed in which you travel [and likely the direction of you are traveling.
And I would guess one would spend a lot of the time in Venus polar regions, and one travel in Venus atmosphere so the one spends less time in the night, and more time flying during the day.