Go Helios! (Score 2, Informative)

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.