IEEE Spectrum has an article on the NASA High Altitude Venus Operational Concept (HAVOC) mission proposals.
Quoting Chris Jones, from the Space Mission Analysis Branch of NASA’s Systems Analysis and Concepts Directorate:
“The vast majority of people, when they hear the idea of going to Venus and exploring, think of the surface, where it’s hot enough to melt lead and the pressure is the same as if you were almost a mile underneath the ocean,” Jones says. “I think that not many people have gone and looked at the relatively much more hospitable atmosphere and how you might tackle operating there for a while.”
...
Put all of these numbers together and as long as you don’t worry about having something under your feet, Jones points out, the upper atmosphere of Venus is “probably the most Earth-like environment that’s out there.”
The article covers the details of the proposed mission, and links to a YouTube animation of the concept: "A way to explore Venus".
Also covered at Geek.com and Extreme Tech.
Related Stories
High Altitude Venus Operational Concept (HAVOC)
The upper atmosphere of Venus, with similar pressure, density, gravity, and radiation protection to that of the surface of the earth, is relatively benign at 50 km. A lighter-than-air vehicle could carry either a host of instruments and probes, or a habitat and ascent vehicle for a crew of two astronauts to explore Venus for up to a month. Such a mission would require less time to complete than a crewed Mars mission.
A recent internal NASA study of a High Altitude Venus Operational Concept (HAVOC) led to the development of an evolutionary program for the exploration of Venus, with focus on the mission architecture and vehicle concept for a 30 day crewed mission into Venus's atmosphere.
Key technical challenges for the mission include performing the aerocapture maneuvers at Venus and Earth, inserting and inflating the airship at Venus, and protecting the solar panels and structure from the sulfuric acid in the atmosphere. With advances in technology and further refinement of the concept, missions to the Venusian atmosphere can expand humanity's future in space.
What is needed?
The first proof of concept identified candidate materials and evaluated them, finding FEP-Teflon (Fluorinated Ethylene Propylene-Teflon) to maintain 90 percent transmittance to relevant spectra even after 30 days of immersion in concentrated sulfuric acid. The second proof of concept developed and verified a packaging algorithm for the airship envelope to inform the entry, descent, and inflation analysis.
Also at The Conversation.
Previously: Cloud Cities on Venus?
(Score: 2) by mhajicek on Friday December 19 2014, @02:44AM
Where's the payoff? At least on the moon you can build stuff for Earth orbit and Earth originating missions.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 3, Insightful) by buswolley on Friday December 19 2014, @02:47AM
That payoff is, i dont give a...
freaking cool. Bubble cities with near Earth gravity...
and sure there are resources.
subicular junctures
(Score: 5, Insightful) by dlb on Friday December 19 2014, @02:51AM
Venus is “probably the most Earth-like environment that’s out there.”
That's more a statement of how inhospitable the rest of the planets are rather than a ringing endorsement of spending one's vacation on Venus.
(Score: 3, Interesting) by Arik on Friday December 19 2014, @02:52AM
Ultimately it seems like a dead end idea to me though. You have to consider not just the feasibility of the project but compare it to possible alternatives, including escaping gravity wells entirely.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by c0lo on Friday December 19 2014, @03:56AM
You either go for solar (and stay in the sunlight constantly) or go for the windpower (and drift with the wind beneath you).
Can't see how you'd have both while riding in an untethered balloon.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 3, Insightful) by frojack on Friday December 19 2014, @05:21AM
If you are drifting with the wind, (which is constantly in excess 400 mph [soylentnews.org]) you aren't going to generate much wind power because it you would have net zero apparent wind. If you could anchor your windmill somehow to the ground you would have a lot of potential, but it would be an engineering nightmare.
Keeping things aloft is hard enough on Earth, doing so on another planet seems overly ambitious for anything but a short visit. And in that kind of wind, even that seems risky in a balloon.
No, you are mistaken. I've always had this sig.
(Score: 2) by Foobar Bazbot on Friday December 19 2014, @06:24AM
I'd tend to skip wind power in lieu of concentrated solar -- you already need a giant balloon for lift, it doesn't seem especially hard to make the top half clear, the bottom half silvered, and a movable target (suspended inside the envelope, sort of like the Arecibo radio-telescope) tracking the focal point. I haven't run the numbers, so I could be way off, but that looks like plenty of energy, and much simpler than wind power.
But if one was to exploit wind power from a floating city, instead of tethering to the ground, one might drop a tether merely to lower altitudes, with somewhat slower winds -- the lower wind differential gives you less power, but also less nightmares, and gives you a convenient control input (at any time, winching the "anchor" in reduces the relative wind -- while the same may be true for a ground anchor, it's not very helpful if shortening the tether pulls you into less hospitable regions of the atmosphere).
And if you wanted to play games with differentials in the atmosphere, I suspect the temperature differential might be a better choice -- again, you drop a weighted line deeper into the atmosphere, but now you minimize drag instead of maximizing it, and the engineers sleep much better.
(Score: 2) by frojack on Friday December 19 2014, @06:52AM
I think the video implied a solar cell covered top on that blimp (or whatever they called it) in the video linked above.
One theory about Venuses rapidly slowing rotation [universetoday.com] is that the atmosphere is imposing a huge drag on the surface, so your idea about a difference in velocity at different levels might actually work.
Also for the exploration mission, the dense atmosphere suggests you would actually need a smaller bag than you would need on earth, no?
For a city, well, that seems a little fanciful to me, so speculation about that is pointless. That same link suggest the atmosphere is mostly sulfuric-acid-laden clouds. Not all that hospitable.
No, you are mistaken. I've always had this sig.
(Score: 2) by Foobar Bazbot on Saturday December 20 2014, @02:35PM
I confess, I did not RTFA/WTFV. But solar cells all over seems like a heavy design, compared with the concentrated solar approach. It does give more freedom in shape -- a blimp-like shape cannot focus to a point -- so may still be a win, depending how much mobility is required.
I've seen the concept discussed several times over the last decade, and I'm sure it was old when I first heard of it. One thing that usually comes up, especially in the context of long-term, large scale presence (whether industrial or colonizing) is leveraging Venus's dense atmosphere by using nitrogen/oxygen breathing air as a lifting gas. If you use Venus's atmospheric density that way, you don't get to use it for reducing envelope volume -- but it's true that a smaller balloon with a more powerful lifting gas may make more sense. (Methane may be a clever choice despite its low weight if one uses it as ascent fuel for the return trip -- a larger fuel tank masses less than a fuel tank + a lifting gas tank. Hydrogen enjoys the same advantage, I guess, though it seems impractical to store it for ascent.)
Full-on cities definitely are quite fanciful, at least for now, but still have a way of inserting themselves in all such discussions regardless. But the argument I was trying (and apparently failing) to make applies equally to any size ground-tethered balloon -- reeling the tether in and out directly affects the balloon's altitude. But with a large-mass balloon attached to a low-mass kite-anchor, reeling the tether in and out moves the anchor, while barely moving the balloon. Thus you can pull the anchor in during high winds, reducing the wind difference to safe levels, or let it out during lower winds, increasing wind difference for more power, without changing altitude (and thus temperature, pressure, etc.).
(Score: 2) by geb on Friday December 19 2014, @12:20PM
You don't need to have the ground involved, as long as there's an exploitable difference in windspeeds somewhere. For example, you might keep a windmill on the blimp part, and dangle a big sail "anchor" into slower winds below.
(Score: 2) by frojack on Friday December 19 2014, @09:15PM
True, almost any method of utilizing a wind speed differential is going to impose some drag on the blimp, which would require a much more rigid structure. You could drag a prop at lower altitude as well. But its the same problem.
At least some portion of that atmosphere is moving at 400mph. Any blimp like structure is pretty much along for the ride.
No, you are mistaken. I've always had this sig.
(Score: 2) by c0lo on Friday December 19 2014, @02:22PM
Not necessarily. Assuming the upper atmosphere - where your balloon is supposed to be - is calm (otherwise your balloon won't resist turbulence for too long), you can drop an "inverted kite" into the 400 mph wind below and harvest some of its energy. Sure, you'll experience a drag (this is why sooner or later you'll get out of the sunlight, so goodbye Sun irradiation as an energy source), but you aren't going to have a zero apparent wind.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by frojack on Friday December 19 2014, @09:34PM
Calm is relative...
TFA says that at the 50km altitude they expect to operate at the wind is only 223.6 mph.
At that speed, they are planning purely drift circumnavigation in 110 hours, so 55 hour days and nights.
Without engines running, or inducing some drag, you will indeed have zero apparent wind (Ask a hot air balloonist). But a steerable kite generator might allow not only power generation, but some degree of cross flow navigation, tacking north/south at will.
No, you are mistaken. I've always had this sig.
(Score: 2) by el_oscuro on Saturday December 20 2014, @07:24PM
Same for a sailboats. I was a noob in a sailboat class and our instructor was having us set the sails in various ways to tack in to the wind. It was a warm July day and the stiff breeze felt good, the boat leaning as we tacked each way, the sails close hauled in to the boat. As we turned around, he had us jibing with the wind, the sails at more of an angle from the boat. During your jibs you could still feel the stiff wind, though it was coming from the stern. We practised this all morning, and just at the end of the session, he had us do a downwind run to get us back top the doc. With the wind at our backs, we set the sails fully extended and sailed directly with the wind. It was the strangest sensation. For the first time all day, there was literally no wind. Everything was completely still and July heat suddenly became oppressive. Looking astern, I could see a substantial wake, and the dock was rapidly approaching. We were definitely moving at a good clip but the sensation was of being utterly still on a windless day. It is an experience I have never had on any other ship.
SoylentNews is Bacon! [nueskes.com]
(Score: 2) by urza9814 on Friday December 19 2014, @02:59PM
Well, not necessarily. Depends on how the winds move and how frequently and rapidly they change. A giant city-sized bubble is going to have a hell of a lot of inertia. If the winds are a constant, uniform 400MPH, you'll get no wind energy. If they *average* 400MPH but are constantly alternating between 350 and 450, then you'll get a hell of a lot. Because the city will stay near 400MPH, and the relative wind speed will be up to 50MPH in either direction.
There's also the possibility of stratified airflow. Could be moving at 400MPH where your balloon is, but 450MPH a few hundred feet below. So you build the turbines on a separate floating island attached to a weighted tether and let them hang below you. Certainly there's some serious engineering challenges there, that'd be one hell of a tether, but if you can build a bubble city on Venus you can probably handle those.
I doubt the winds are uniform enough to make wind power *impossible*. Of course they could be and you might be right, I don't have a clue. There's got to be some variation though, simply because solar energy isn't hitting the planet uniformly.
Given the density of the atmosphere on Venus, I wonder if these bubble cities could be *actual* lead zeppelins... ;)
(Score: 2) by frojack on Friday December 19 2014, @09:41PM
You are right about the stratification.
They are expecting about 236mph constant (more or less) winds at the altitude they were planning to use according to TFA.
The winds drift north, so they were going to power their way back south during the day when they had solar power.
What ever power you harvest by utilizing stratification of wind speed will obviously apply some (probably forward) drag to the vehicle so it will in effect be traveling faster than the prevailing wind at altitude.
No, you are mistaken. I've always had this sig.
(Score: 2) by HiThere on Friday December 19 2014, @08:58PM
The real problem is "What's the payoff?". You can't access non-gaseous raw materials. You can't see much more than a satellite could. I can't see the sense even as exploration. Since you're untethered you can't stay over the same area. If you plan to control robots on the surface, a satellite is a better choice, since it will be over the same area at predictable times.
So it's a neat idea as a tour-de-force, but seems of no real value. The Moon, orbital factories (requires either Lunar lauchers or asteroid capture), Mars, the Asteroids, the moons of Jupiter, even Mercury make more sense. Each have their difficulties to overcome, but each also has some real value.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by richtopia on Friday December 19 2014, @04:23AM
The same argument can be said for all heavenly bodies. The debate is more likely Venus or Mars.
Some benefits of Venus:
1. Closer to sun. This means more solar irradiation, and shorter year. The shorter year means more and easier launch windows
2. Closer to earth. Less time traveling between the two planets is less radiation (still a bitch though)
3. Near Earth gravity
4. An atmosphere. Both Mars and Venus lack a magnetosphere, and the atmosphere of Venus actually protects from solar radiation (although not as good as a Martian bunker)
5. 1ATM atmosphere available, where this mission occurs
The video was a little too flashy for my taste. However I'm totally on board with exploring Venus, particularly a balloon drone. And saying we should explore Venus does not say ignore Mars, as many of the challenges faced are the same for both planets, particularly with humans traveling.
Moral of the story though, more money needs to go to space exploration.
(Score: 2) by c0lo on Friday December 19 2014, @04:39AM
2. Closer to the Sun means not only more solar irradiation, but more solar wind (flux increasing with the square of inverse distance. I'm too lazy to integrate 1/x^2 for a trip between Earth and Venus/Mars and compare the two, but there may be something with your point 2).
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by frojack on Friday December 19 2014, @05:30AM
1. Close to the Sun means a deeper (solar) gravity well - return mission will need more fuel than for Mars.
Do you spoze you could sling shot slightly closer to the sun, and get that ride for free?
No, you are mistaken. I've always had this sig.
(Score: 2) by c0lo on Friday December 19 2014, @02:14PM
Mercury may be used for a slingshot (coming from behind Mercury, getting "dragged" while falling into the grav-well of Mercury, letting Mercury just a bit slower on its orbit around the Sun and the ship with an extra speed).
No matter what you do, the time to get back to Earth will be longer than a Hohmann transfer.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by GreatAuntAnesthesia on Friday December 19 2014, @11:17AM
Build floating city. Make it big. Get it as close to self-sustaining as possible. Maybe even get it to the point where it is producing things that are useful for the construction of the next one. Build another one joined on to it, bigger than before. Bear in mind that these things are potentially huge, being just bags of air they cover a lot of area without using a lot of material. Build another, and another, all clustered together, above the clouds, all on the sunny side of the planet.
Eventually, you will have enough of them to seriously affect the planet's albedo. Assuming a decent amount of the cities' waste heat is radiated back into space, you might ultimately be able to slow down Venus' runaway greenhouse and lower the temperature/ pressure to a point where you can put things on the surface. Of course, as the atmosphere cools down, it will get denser and you cities will gradually sink, but their buoyancy is such that they will always be at the altitude where the atmospheric pressure is comfortable. Maybe the cities will eventually land.
Import a little it of water (Perhaps Ceres =-) and who knows, maybe one day terraforming "Earth's Twin" might one day be a possibility.
(Score: 2) by TK on Friday December 19 2014, @08:29PM
That's the coolest premise to a science fiction novel I've read all day.
The fleas have smaller fleas, upon their backs to bite them, and those fleas have lesser fleas, and so ad infinitum
(Score: 2) by HiThere on Friday December 19 2014, @09:05PM
IIUC, the materials for building water are still present on Venus, just improperly combined. With enough energy you could synthesize it (until you run out of Hydrogen). So no need to import water. Just don't let it escape after you make it. (One of the problems is UV splitting of water into 2H2 + O2.) I don't think you can roof the planet, so any water you add to Venus will be even more temporary than water you add to Mars. On Mars it will tend to freeze out of the atmosphere, so it will resist being split. And the radiation that splits it is a lot weaker anyway. (The same inverse square law that means you need more solar cells on Mars.)
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 3, Interesting) by d(++)b on Friday December 19 2014, @07:34AM
A lovely Larry Niven tale about life in an atmosphere.