They have been considered. Well - mainly balloons, so they just move with the atmosphere, but airships also for Venus. And a couple of balloons have actually flown already on Venus, the two Vega program probes
Vega balloon probe, Udvar-Hazy Center of the Smithsonian Institution. Photo Geoffrey A. Landis.
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This artist's impression shows the European Venus Explorer - a proposed ESA mission to Venus (submitted but not approved). The Russian Vega probes in 1985 would have looked similar.
The Russians had ideas for cloud colonies in the Venus upper atmosphere in the early 1970s:
Geoffrey Landis is a proponent of setting up these colonies. The fast winds in the Venus upper atmosphere are no problem for floating balloons or airships that move with them, indeed they help, they mean you have a “day” of only four Earth days. Will We Build Colonies That Float Over Venus Like Buckminster Fuller's "Cloud Nine"?
Then there’s also the idea of the Havoc Mission, a study from NASA
HAVOC mission. Proposal to send robotic missions to Venus followed by airships as shown. At the same "above the cloud tops" level as the cloud colonies.
In the case of Mars, the atmosphere is a near vacuum, but still, light gases such as hydrogen, helium provide buoyancy, no matter how thin the air is - just means you need a larger balloon for the same mass of hydrogen or helium, indeed for the same payload too, which is why weather balloons start off only partially inflated and get larger and larger as they go up into the upper atmosphere.
The CO2 there is denser than our atmosphere so the balloons on Mars provide more lift than you’d get if you went to a height in Earth’s atmosphere with similar pressure.
The Mars storms are not a hazard because though the winds are fast, in the thin atmosphere, there’s not much momentum - it’s similar to a gentle breeze on Earth that can just barely move an autumn leaf. An autumn leaf on Mars would perhaps be moved a bit, anything heavier and reasonably dense won’t be. The dust moves around in the wind because it is as fine as cigarette dust.
This is project Archimedes from the German Mars society originally planned for 2009 but never flown
This is the idea of the Solar Montgolfiere Balloons for Mars
A montgolfier balloon is open underneath so relies on heating to stay aloft.
This is about the idea of a Mars balloon considered by NASA
And just to mention as well, there’s the idea of orbital airships as well, from JP Aerospace.
DIRIGIBLES IN SATURN’S ATMOSPHERE
Also you can use airships even in gas giants, for instance for exploring Saturn’s atmosphere. You might think “how is that possible as what can float in an atmosphere of hydrogen and helium?” Well hot hydrogen and helium can do the trick. It’s just like a hot air balloon on Earth. So yes you could have dirigibles in the Saturn atmosphere for instance. Jupiter too. I’ve heard it talked about for Saturn in the context of rather far out ideas of colonizing Saturn with floating cities in its atmosphere, while Jupiter’s gravity is a bit too high for that to be comfortable. But for robotic spacecraft both would be possible in theory. Don’t know of any worked out missions for either though. Just discussions.
AIRSHIPS TO ORBIT
A balloon filled with hydrogen or helium could rise almost indefinitely - if the skin is light enough, even close to the boundaries of low Earth orbit. This is a very low cost method because no fuel needs to be expended to do the lifting itself.
JP Aerospace plan to make airships that would rise to orbital platforms at 200,000 feet - so that's 60 km, in the mesosphere - above the stratosphere, near vacuum conditions.
They have the current altitude record for an airship for an unmanned but manoeuvrable airship of 95,085 feet, or 29 km
JP Aerospace Airship Flies to the Edge of Space, Smashing the Existing World Altitude Record
The maximum height achieved with any ground launched balloon so far is 56 km with a NASA experiment Bu60-1
This is the highest flying balloon ever at 56 km, on the edge of space
ISAS | BALLOONS:Research on Balloons to Float Over 50km Altitude / Special Feature
JP Aerospace plan to build airships that set off at a level higher than the highest flying balloon ever - huge airships made of such light materials that they couldn't be inflated at ground level. They would be constructed in the “dark sky” platform high up in the atmosphere, which would also be a tourist destination in its own right.
These would be truly orbital airships - slowly accelerating to Mach 20 and greater.
When they set off from their base station at 200,000 feet (60 kms), they would be just floating. It's almost a vacuum inside the ship, yet still, because it is filled with hydrogen or helium, contained by the skin, then the lighter atoms of hydrogen or helium will float on the denser almost vacuum of oxygen / nitrogen outside it. LEO starts at around 160 km Low Earth orbit
They would accelerate to orbit slowly over several days, by using ion thrusters. The V shape gives it aerodynamic lift. It has several phases, subsonic, then they break the sound barrier, and then as they get faster they reach hypersonic speeds, which means that it’s traveling so fast that the air gets pushed back along the side of the airship.
First they use a combination of lift and velocity - and eventually travel at orbital velocity at levels too high to get noticeable lift.
This idea of Mach 20+ airships accelerating to reach orbital velocity may seem absurd at first, it did to me when I first read it. But the more you think about it, the more it begins to make sense. We launched several balloons to LEO in the Echo program, so there is no problem with balloons once they reach LEO. The problem is the transition between high altitude and LEO. For that, we want to find out about suborbital balloon flights. Those are rare.
An early experiment sent one of these balloons into a sub orbital hop which it survived for most of the hop and disintegrated eventually. When it did explode, this was mainly because they made a mistake and left too much gas in it. That isn't much by way of experimental data, as this seems to be the only example of a suborbital balloon flight to date. Also that's with a small balloon not the huge kilometer scale airships of JP Aerospace.
Still, what data there is, is reasonably promising that the high speeds of the balloons won't be a problem so long as they are well above most of the atmosphere in close to LEO vacuum conditions by the time they approach orbital velocities. At any rate, JP Aerospace don't consider this to be their main challenge. You can hear John Powell, the man himself talk about it in a recent Spaceshow talk, and decide for yourself. They have a very interesting philosophy also, it's a company that does its development in the slow lane. They've been working towards this for decades and finance their development by the discoveries they make along the way.
If this works out, then we’d have a way to go by airship to orbit from Earth, then to the Venus upper cloud decks, and they would also be able to land on Mars too.
Find out more here: Guest: John Powell. Topics: Updates on JP Aerospace and the Airship To Orbit program.
So there’s actually a fair bit of interest in this idea which is certainly a good one, but we have only sent two balloons to another planet so far, the two Russian ones to Venus.
There’s a strong tendency for space agencies to continue to use tried and tested methods, not surprising when each mission costs hundreds of millions of dollars, or more. Despite many ideas for balloons, gliders, hopping robots, and so on, most of the missions have followed the more conventional idea of a wheeled rover. They haven’t even explored “whegs” yet - wheels with legs which are better for traversing rough terrain.
Perhaps once costs to launch to Venus or Mars are reduced, and also with the possibility of miniaturized spacecraft, interplanetary cubesats, and such like, maybe we’ll see missions like this, proposed so many times, actually sent to the other planets?
And JP Aerospace are moving slowly but steadily towards their goal of an orbital airship, who knows, maybe some day they will achieve their goal and that would be a gamechanger if they did.
See their blog. JP Aerospace Blog
And they have just released a new book
See also
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