Airships

[Kerbface]

I was just looking at the JP Aerospace site and reading a little about how balloons have been used to reach space and it got me thinking about airships/zeppellins/balloons. It seems there is a project at the moment designing a new type of airship. http://www.businessweek.com/videos/2013-01-22/a-giant-floating-airship-could-be-future-of-flight

I was wondering, since I don't know much, what some of the more knowledgeable folks here thought about the possibility of using airships terrestrially and even for orbit (as planned by JP aerospace) in the future.

And I had a thought, but it may be unfeasible. If you had a hull with enough structural integrity resisting implosion, wouldn't a depressurised airship creating a near vaccuum be very efficient?

[Eric S]

And I had a thought, but it may be unfeasible. If you had a hull with enough structural integrity resisting implosion, wouldn't a depressurised airship creating a near vaccuum be very efficient?

In general, a hull with that much integrity tends to outweigh the air it would displace, especially at high altitudes.

On the other hand, I have experimented in KSP with balloon-based launches (using a balloon to lift the craft out of the thickest part of the atmosphere) and landings (taking the place of parachutes).

[Kerbface]

In general, a hull with that much integrity tends to outweigh the air it would displace, especially at high altitudes.

On the other hand, I have experimented in KSP with balloon-based launches (using a balloon to lift the craft out of the thickest part of the atmosphere) and landings (taking the place of parachutes).

Yeah, I was thinking the weight of such a strong hull would probably be the factor that stopped it from working. Still, maybe one day there will be a way to make a strong, rigid, lightweight hull that can hold a vacuum.

And what you mentioned was another thing I was thinking of, balloons to get vehicles to a certain height before they launch. I would imagine it would be much easier to make a SSTO vehicle with that method, assuming you don't count the balloon as a stage.

[Pyotor Gagarin]

Wikipedia has a decent overview of the "vacuum airship" idea.

The main problem is that structural integrity to resist implosion weighs a lot more than the small amount of lighter-than-air gas it would take to provide the same support from the inside. It's one of those cool ideas that has just never been practical in reality:|

[Moach]

sounds like a lot of trouble for the 14% relative buoyancy cost of using good ole' helium

[Kerbface]

I know hydrogen has been the cause of many firey problems in the past, but is helium really a plausible fuel for airships anymore? It's becoming so rare and scientists need it.

Could hydrogen be used again in the future? I mean surely we've advanced our structural technology and safety standards since the 30's.

[Kryten]

Science has advanced. People haven't. It's going to be almost impossible to get people onto a hydrogen airship if all that that makes them think of is hindenburg, regardless of how safe it actually is.

[Kerbface]

...Well, that's a bit annoying. I mean I wouldn't use them in a war or something, but if it's safe for regular use, why not? People didn't stop using big ships after the Titanic sank.

[Eric S]

And what you mentioned was another thing I was thinking of, balloons to get vehicles to a certain height before they launch. I would imagine it would be much easier to make a SSTO vehicle with that method, assuming you don't count the balloon as a stage.

If the Hooligan Airships parts are realistically balanced, it wouldn't make enough of a difference to a rocket capable of achieving LEO to make the complications worth it (and the Hooligan parts definitely have fewer complications than a real life equivalent would have), but for a sample return from the surface of Venus, it could make the mission drastically more feasible. In KSP at least, balloons also work well with landers/rovers. They're the best uprighting mechanism going if there's an atmosphere, and on my first Laythe landing, I even used a balloon in place of parachutes so that my normal not-so-precise landings would still allow me to set down on an island instead of in the water.

[Caldari Navy]

The titanic didn't explode in a big fireball also the titanic went down slowly the hindenburg happened in a few seconds.

I wish we still had airships though.

[satcharna]

Airships would make quite decent transports, but only within an atmosphere. They can carry more weight than a comparable plane, making it possible to have both cheap budget flights with lots of people packed into a single airship, or luxury "air-cruising" for those with a bit more money to spend. They're not practical for space launches though, as the envelope needed to encompass the lifting agent (or lack thereof) would have to weigh more to not rupture, but that would make it too heavy to get far enough away. They could have a lot of potential for probes and landers going to places with a thick enough atmosphere, working essentially as very low-flying satellites, potentially avoiding surface problems a conventional lander would have (such as cold geysers). One idea would be a probe suspended below a balloon, which could explore gas giants up close, bypassing some of the magnetic field effects that make it difficult to examine gas giants from a distance.

The Hooligan Airships parts are not particularly realistic, by the way. I still like having a blimp-probe on Laythe.

Edited May 2, 2013 by satcharna

[PIRATEONTHERUN]

I wonder if they could make something like areogel with a non-flammable membrane (meaning the solid that forms the bubbles) and fill it with hydrogen to use as a lifting "gas".

[satcharna]

From NASA's Stardust FAQ:

Would it be possible to create aerogel lighter than air by using helium instead of air?

Aerogel cannot be made less dense than air by filling it with helium. You might be able to make it less dense than the surrounding atmosphere by filling the aerogel with helium and then placing it in an atmosphere of radon or possibly xenon.

Helium isn't much heavier than Hydrogen, so, while it might be possible, it still wouldn't be practical, especially not for getting high enough to where it is cheaper to launch with aerogel than with rockets.

[drakesdoom]

The structural issue with a vacuum balloon comes from the pressure gradient from outside to inside. What if we made a hydrogen balloon that is only slightly resistant to implosion and as it rose through the atmosphere pumped the hydrogen from the balloon thru a compressor into the rocket for use as propellant. The pressure gradient would be maintained so as not to crush the balloon and once the rocket is released and in flight merely open the seals and let the balloon slowly fill with some air as it descends for reuse.

Crazy maybe, but if it is crazy is what you wanted.

[Kerbface]

The structural issue with a vacuum balloon comes from the pressure gradient from outside to inside. What if we made a hydrogen balloon that is only slightly resistant to implosion and as it rose through the atmosphere pumped the hydrogen from the balloon thru a compressor into the rocket for use as propellant. The pressure gradient would be maintained so as not to crush the balloon and once the rocket is released and in flight merely open the seals and let the balloon slowly fill with some air as it descends for reuse.

Crazy maybe, but if it is crazy is what you wanted.

That sounds like a really clever idea.

[shadowmane]

The hydrogen is not the reason the Hindenburg burned up. Look it up. It was the fact that the outer shell material was highly flammable. Most of the hydrogen escaped unburned.

[Domfluff]

The hydrogen is not the reason the Hindenburg burned up. Look it up. It was the fact that the outer shell material was highly flammable. Most of the hydrogen escaped unburned.

That is one theory, but it's hotly contested - the main argument against it is that many other hydrogen airships went down in flames - this kind of fate wasn't especially uncommon (particularly in WW1 when the fighters started using incendiary bullets), it's just that the Hindenburg was very famous, in America and caught on camera.

Personally, I'm not sure. I certainly don't think the hydrogen helped, but if the theory is correct it wouldn't have mattered either way.

[falofonos]

If I want to make my airship out of magnesium foil, match heads, aluminum powder and iron oxide then I shall!

What do you mean fire risk? Almost all of the candles will be in the passenger gondola!

Edited May 9, 2013 by falofonos