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Unmanned Aerial Telecom Relays
Brussel writes "SkyTower in collaboration with the Japan Ministry of Telecommunications (CRL/TAO) and NASA has successfully completed a series of commercial telecommunications tests -- the world's first from more than 60,000 feet in the stratosphere. The tests, which began three weeks ago, were conducted from Pathfinder-Plus, an unmanned solar-electric aircraft developed by AeroVironment." There's another press release here.
Yes they would; lower fuel consumption, much greater endurance, less risk of a catastrophic failure - and lots of area for solar cells that can help power the relay.
You have to design a special ship, normal airships fly relatively low and their useful load drops off quite rapidly with altitude. You have to think about building BIG for quite a small payload. Then consider things like reliability, redundancy and UV light eating away at the envelope. But it should be doable.
A British company, the Advanced Technology Group is prototyping just such a relay. It's called StratSat and the prototype could fly in the next year or two.
Best wishes,
Mike.
There are a series of amateur radio satellites in orbit sponsored by members of The Radio Amateur Satellite Corporation and other organizations worldwide. They are free to use worldwide by anyone holding an amateur radio license. Most of these satellites are in low earth orbit, which means that they may make several passes a day. It does not take much to get started. You can communicate with other radio amateurs through these satellites with nothing more than a handheld antenna pointed at the sky and a handheld radio clipped to your belt. I use this antenna.
Yes, I know that I can whip out my cellphone and talk to anyone with much less effort. But I am a geek and this is much cooler (and fun!)
If you are in the U.S. check out the American Radio Relay League's web site for more information on getting licensed. If you are outside the U.S., check the above web site for information on getting licensed in your country. It's easy!
A while back I was able to go to Dryden Flight Research Center and see the Helios and talk to one of the head engineers about the project. The plane itself has a huge wingspan, larger than that of a 747. I don't recall the exact figure, but I'm sure you can find it on NASA's website. As several people have commented, it is better structurally for the wing to be very flexible. This allows the plane to absorb shock encountered in flight, with an instantaneous shock resistance of > 30g's. At that time, the idea was to operate the plane at an altitude of 120,000 feet, which would put it above most weather. There is some risk involved with takeoff and landing, but this is true for any aircraft. Besides, a Helios flight may last up to 60 days, which gives leeway to plan takeoffs and landings around weather conditions. The real advantage of the Helios over a satellite is maintenance. If the electronics in a satellite fail, there are few options for fixing or recovering the satellite. At a cost of over $80 million a pop, that's an expensive risk. With a Helios, which may cost around $3 million, servicing the payload is much easier. The plane itself has such a low glide ratio that in the original tests, they shut off the engines at night and let the plane glide. It only lost about 15,000 feet over an 8 hour period. In the morning the engines would come back on and the plane would regain altitude in a couple of hours. I am not sure if they still do that, but it's a great way to conserve electricity for use with a payload. Anyway, should the engines fail there is plenty of time to land the aircraft. I'm excited to see these successful test flights, as there are many benifits the plane could provide. The obvious application is cellular phone coverage, but at a much lower cost. This means extending cellular coverage to areas of the world that are underserviced by current telecommunications satellites (i.e., a large portion of the African continent). It is also possible to transmit power via a microwave radio signal, thus these could also be used to provide electrical power to very remote areas. The Helios won't, and shouldn't, replace current infrastructure but it may be a great tool for meeting the challenges of technological development in underdeveloped parts of the world.