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19th Century Airship Technology for Port Security
fenimor writes "Airships - known today mainly for advertising flyovers at football games - are the core of a new coastal surveillance system in development for the the U.S. Department of Defense. These
stationary platforms 25 times the size of a Goodyear blimp will be equipped with an array of cutting-edge equipment for remote sensing, communications, and risk analysis, providing surveillance coverage over a surface area of 500,000 square miles from an altitude of 70,000 feet."
Currently the USCG employes a pair of blimps "Fat Albert" on Cudjoe Key to watch for dope smugglers, air traffic, etc.
Ob: SovietRussia: For Soviet Russia YOU spy on the blimp!
A feeling of having made the same mistake before: Deja Foobar
Conventional arms can't easily hit a target a few thousand feet above you, let alone SEVENTY thousand feet.
Even fighter jets have trouble exceeding 50-60 thousand feet IIRC. Only specialized aircraft (Scaled's White Knight is one such example) can reach these altitudes.
retrorocket.o not found, launch anyway?
Yes, sir! I'll get right on it.
Blimps are go, sir.
Even a 50 caliber (12.7mm) or the old Russian heavy-machine gun the 14.5mm can't come close to this altitude.
g ro und/m2-50cal.htm
g ro und/m82.htm
.300, 30.06, 7.62, 7 Magnum, and so forth)
http://www.globalsecurity.org/military/systems/
http://www.globalsecurity.org/military/systems/
Maximum effective range on equipment-sized targets: 1800 meters
Now, in the United States, a 50 caliber sniper rifle isn't a "conventional arm". It's a special application rifle used in the military and by a very small special core of long distance shooters.
In the United States, the most common rounds are 5.56mm and a wide variety of 7 to 8mm rounds. (.30,
There are much cheaper alternatives in the works, such as the High Frequency Surface Wave Radar being developed by Raytheon Canada and Defence Research Development Canada.
The big problem with conventional radar is that it only works in line-of-site, but Raytheon's SWR-503 Surface Wave Radar uses high-frequency radar waves that "wrap" around the curvature of the earth. The system has been proven to detect and track aircraft, surface vessels and icebergs out to 500 km from the shore in a sector of up to 120 degrees. Suspicious objects can be investigated by satellite, surface ship, patrol aircraft or very cheaply & covertly via unmanned drone.
Canada plans to install an array of radar installations along the East Coast in order to provide a seamless picture of all maritime activity occuring in the country's economic zone. Similar research is being carried out in the US, Australia and other countries. This seems like a much more effective use of resources than a massive blimp installation
When you have nothing left to burn you must set yourself on fire
Weather tops out at the Tropopause, this would be above it as the Tropopause most of the time. Wikipedia has it at 6 km (4 miles) at the poles to 17 km (11 miles) at the equator.
Your big thunderheads in the Midwest "anvil" out at about 40-50,000 feet.
http://en.wikipedia.org/wiki/Tropopause
Do a blimp search at http://www.ntsb.gov/NTSB/query.asp and you can see that since 1962, there have only been 23 accidents in the US and only 2 of them have been fatal. These things are well nigh indestructible.
...But I digress. TREMBLE PUNY HUMANS!ONE DAY MY SPECIES WILL DESTROY YOU ALL!
You're right that helium escapes into space, at the surface temperature of the Earth, helium atoms have escape velocity (or close enough to it, accounting for the Maxwellian velocity distribution). So unearthed helium eventually escapes away from the planet. Hydrogen does as well, but I believe all other gases are heavy enough to remain bound.
I work in cryogenics here in the USA, and we routinely let helium gas escape into the air (eg, when inserting a room-temperature insert into a dewar of liquid helium). In Europe, from what I understand, most labs collect this boiled-off helium gas, and somewhere else they can re-liquefy it. Don't know what Canada, South America, Asia, or other places do, though.
One of my professors was explaining why we don't recycle the helium here in the USA. He said this is because helium is typically 'mined' at the same time as companies dig for oil and natural gas. Thats where the large helium deposits are found. The market for helium is so small that petroleum companies want to just let the helium gas escape, it's not worth their time to collect/purify/sell it.
The NSF, however, doesn't want this to happen (environmental issues and maybe to capture more of the rare He3 too), and was able to influence American-based petrol companies to collect and sell the helium instead of wasting it. In exchange the oil companies need to have enough of a helium market to do this, so that's why Helium gas is typically not recycled in the USA, so the oil companies will sell it instead of let it go.
As one side note - you need to use alot of He gas to make recycling it cost effective, so only a few institutions in the USA recycle He. In Europe the density of such labs is much higher, so it's easier for Europeans to recycle this. Not sure if He is recycled in South America or Asia, though.
So unless my professor is entirely bullshitting, the problem stems not only from many labs not recycling He, but from global petrol companies letting the He gas free instead of capturing it themselves. But as to your original question, there shouldn't be significant amounts of helium used in the airships compared to global supply.
make world, not war
Problem with satellites is, they move really fast relative to the ground, so it's hard to use them to track movements of people or vehicles over time. Spy satelites aren't put in geosynchronous orbit because that's really far away and it would be impossible to see stuff from that altitude.
I would guess that blimps could loiter overn an area for a really long time compared to sats. Plus, you could upgrade them over time, something you can't do with satellites.