Lighter than air technology was very popular at the beginning of the twentieth century, but the Hindenburg disaster in 1937 caused people to lose interest in this type of aircraft.
Since then there has been new research and development for both civilian and military applications. Innovations in materials and other technology has caused a renewed interest in lighter than air devices.
Lighter Than Air Aircraft
All lighter than air vehicles use a lifting gas to provide their lift. The most common types of lifting gas used (since hydrogen was banned after 1937) are helium and hot air. Blimps use helium and large balloons use hot air. One thousand cubic feet of hot air has a lifting capacity of approximately twenty pounds. One thousand cubic feet of helium will lift approximately three times that of hot air or sixty pounds. Hydrogen has a lifting capacity that is approximately ten percent higher than helium.
Blimps and balloons are usually what come to mind when someone mentions lighter than air aircraft. These are unique and large enough to draw attention. They have applications in aerial photography, aerial advertising, surveillance and sports events. Radio controlled
blimps make a very cost effective platform for flying billboards. The retention of seeing an ad on the side of a blimp is much greater than the television, radio and static written ads that we are exposed to all of the time. The radio-controlled blimp is ideal for video photographic needs. They can fly much lower than a fixed wing aircraft and are less expensive to operate than a helicopter.
Near Space Applications
Near space is defined roughly as that region above controlled air space (approximately twelve miles high) to about sixty miles high (lower limit of space.) This region offers advantages for both civilian communications and military applications over the present satellite system in use today.
One advantage would be cost savings. Putting satellites into orbit is very expensive. Another is safety. Think how crippling it would be if one or more of our satellites stopped functioning. It would be much faster to get a vehicle into near space than getting one or more twenty thousand plus mile into space.
Our communications needs for both voice and data are increasing at an exponential rate. Future wars are going to be fought and won by technology. Data to satellites travels at the speed of light, but there is a delay to travel twenty thousand miles up and twenty thousand miles back vs. traveling sixty miles up and sixty back. This delay could be important if you are trying to lock on to a missile pointed in your direction.
There is an increasing need to develop lighter than air platforms that can be parked in this near space region. Tests have shown that line of site communications can be increased from ten miles to over four hundred miles by utilizing near space platforms. This offers a tremendous advantage for both civilian and military communications. Having several of these platforms will provide the ability to cover thousands of square miles areas.
Several companies and universities are doing research on near space vehicles. If you do a search on the web using a poplar search engine you will find over two million entries.
Lighter than air technology has many advantages, however, there are engineering obstacles that have to be solved before it is used in large quantities. The volume required to lift a payload that is practical will limit some applications. There will always be a need for satellites, but lighter than air vehicles will provide increased capabilities for future needs.