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Lockheed's High Altitude Airship
swordboy writes "Lockheed Martin has just awarded a contract to UniSolar Ovonic regarding development and delivery of flexible, lightweight solar cells for the U.S. government's High Altitude Airship security project. The proposed 500-foot-long dirigible is to fly at a stratospheric 70,000 foot altitude - above both jet stream and severe weather. The thin-film solar technology, although low in peak conversion efficiency, can potentially deliver a whopping 2500 watts/kilogram. This is the same technology as the previously discussed GE organic LED project - just with the physics in reverse. Broadband communication blimp, anyone?"
The organic LED based technologies (polymeric / organic /nanostructured / Titania / Gratzel / Graetzel) cells are not yet ready for prime time, though they have huge promise. Check out Konarka or Nanosolar. GE and HItachi are also fooling around with this. The idea is that you can make solar cells out of TiO2, which is almost infinitely cheap in industrial quantities (see here toothpaste or white paint.)
Uni-Solar's product is in fact based on conventional silicon, just like 90%+ of the market today. The difference is that instead of slicing it out of crystals, they sputter it onto a backing, enabling them to make, e.g. peel-and-stick solar panels for commercial raised seam roofs, a conventional shingle for residential roofing, as well as, here, a flexible backing product for airships. Many are working in this area; it's sort of the next generation for solar cell cost decreases (which have come down by more than half in the last ten years; world production doubled between 2000 and 2003 - however, we're going to run out of tricks with conventional silicon within about 5 years at this pace.)
I find everyone's obsession with conversion efficiencies touching; what sense does it make when your fuel source is infinite and free? Area - related costs are subtle, so focus on this: with solar, efficiency matters not at all - the be all and end all is cost per watt.
Just so somebody else doesn't have to look this up, geosynchronous orbit is at 19,323 nautical miles, while the various radar and broadband blimps are proposed to be at around 12 miles up. So satellites have an inherent 100ms delay each way, the blimp version would only have a one-way delay of 0.06 ms.
They are a heavy engineering company. But they do indeed have a new ship which is flying now, the Zeppelin-NT:
http://www.zeppelinflug.de/pages/E/haupt.htm
Cargolifter were going to create a f*cking *huge* ship which with a cargo capacity of 160 tonnes but ran out of money. When I say "f*cking huge", imagine an ocean liner floating in the air in front of you.
http://www.cargolifter.com/
It seems that military spending is needed for these kinds of projects to succeed.
Government of the people, by corporate executives, for corporate profits.
My initial thought was that hyrdogen being a smaller molecule would leak out more rapidly, though perhaps not at a significantly higher rate. A quick googling reveals this to be false. Helium actually sneaks through mylar faster than hydrogen. At very low temperatures it looks to be about 50% faster. Dupont data, see page 3 I don't know what film they are using, but the others I checked were similar.
Given that the limiting factor for staying on station is gas leakage, hydrogen would seem to be a winner.
> If it gets shot or blown up...
I don't think gas type will be much of an issue. Either way the blimp will be a loss. The spectacular combustion of the hydrogen will happen well away from anything else that can burn.
The safety issues of hydrogen are probably only an issue on the ground. You probably would not want to put an inflated hydrogen blimp in the hangar for maintanence, so if the life cycle of the blimp involves hangar work like leak detection and repair helium looks better.
The final reason may be what Lockheed harps on a couple of times... Lockheed has the expertise in getting FAA certification for blimbs. The FAA is a variable that could effectivly kill the project, so project risk management probably dictates that they deviate as little as possible from the previous designs.
logical uses I can see are as replacements for cell towers
Not a chance, go read up how cellphone networks operate and you will see why this will not work.
cell towers need to be low, and lots of them in an area there are a very small number of frequencies and therefore you need to keep that number of calls in a cell area so that you can carry more calls in a geographical area...
cellular requires many small low towers to cover a metro area. you see taller towers in rural areas as the chance of saturating that cell site are much smaller in hickville compared to manhattan.
Do not look at laser with remaining good eye.
A few years ago, I was military, and in Space Command, but nowhere where I could make policy. But we discussed things like this since I was in space launch. I predicted that, if satellite makers were smart, that balloons/dirigibles/flying wings would replace many, but not all, satellites. And this includes military satellites as well, if the USAF gets smarter.
Specifically, one of the things Air Force likes to talk about is operationalizing space, i.e., launching a satellite like it was a sortie of a fighter or bomber aircraft. That's not going to happen anytime soon, at least with the rocket types. But a squadron of high flyers with interchangeable electronics packages could easily be 'operational'.
However, for communications satellite, especially regional broadband communications (think army operations in Iraq), such a 'satellite', deployed when necessary, could be highly useful. Operations over, comm needed in Korea, send it there. It breaks, bring it down, repair and send it back up. Out of fuel/power send up the spare or just send up two. How many satellites can that be done for? When they are done (Hubble) the expense is enormous
Comm is not the only thing it could use a low-sat. Optics and Radar are prime candidates. Science, both looking up and looking down are possible. Even consider the GPS satellites. You do need your base system in space. However, if you needed increased accuracy in an area, put a high flying balloon/dirigible, flying wing, with the GPS innards and fly it in the general area. If done correctly, it could give receivers an additional satellite, improve the solution.
Our founding fathers removed the guys in charge. Be American. Vote incumbents out.
The way I see it, the final product is going to have a payload capacity in excess of 20,000 lbs.
According to the linked articles the payload will be a mere 4000 lb, despite the dirigible's massive size. It makes sense, since an airship's bouyancy is created by the difference in density betwen the airship and the air around it. At sea level this large airship would have much greater lifting capability, but way up there the lifting gas won't be that much lighter than the thin atmosphere.
By the way, some back of the envelope calculations show that this thing would have about 70% of the volume of the LZ-129 , the famous Hindenburg. The Hindenburg was considerably sleaker too, at 804 feet long vs 500. The Hindeburg carried 50 passengers and 50 crew, which alone without luggage or cargo would amount to something like 15,000 lb; in addition, the ship could carry 11 tons of cargo.
So we're talkiing very neary 40,000 lb of payload capacity for the LZ-129 vs. 4000 for this beast. In part this is because of LZ-129's 40% greater volume (lifting gas only - overall it had 4x the volume), possibly the use of hydrogen gas (doesn't say whether the ship in question will use H or He). But mostly it is due to the fact the LZ-129's normal operating altitude was on the order of 200m.
An airship to lift 20,000 lb to the altitude this one will would, all other things being equal, have to have five times the volume. Conservatively, we are talking about something on the order of 850 feet long; possibly a bit less because of increased volume to surface ration. Undoubtedly it would be the largest flying machine every built.
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Nice try, but no.
If you were doing this in a sensible way you'd actually "fire" the space craft from the launch platform somehow (e.g. drop it).
The craft then lights its rocket and off it goes. It doesn't have to push _against_ anything.
Think about what happens in a vacuum...