A HALO (High Altitude Long Operation) aircraft is an aircraft designed to act as a very high altitude receiving and transmitting tower, circling a metropolitan area and providing Broadband telecommunication service at data rates up to 5 Mbps to homes and up to 25 Mbps to business users with dedicated lines. Angel Technologies plans to launch a HALO-based series of metropolitan area networks ( MAN s). In each city, a single aircraft flying at about 52,000 feet will be able to service home and business users over a 60 mile area. Three aircraft will take turns, each flying an 8-hour shift. Users on the ground will mount a small external antenna outside their home or building. The airplane will link users with each other or with Internet service providers ( ISP s) and telephone company offices for connection to networks outside the metropolitan area. Tens or even hundreds of thousands of users can be serviced. Rates are not yet announced.
The aircraft, called the Proteus, is being built in California by Scaled Composites, a subsidiary of Wyman-Gordon Company. It is powered by twin turbofan engines and is designed to have an "efficient high-altitude loiter," to be easy to maneuver, and to sustain flight at altitudes as high as 60,000 feet for 14 hours with a payload of up to 2,000 pounds. Extendible wings allow it to carry a range of payloads. The first "proof of concept" Proteus has been successful in preliminary flight tests.
Unlike the telecommunication satellite systems now being developed, a HALO system can be launched for one city at a time. (The HALO aircraft flies at about a tenth of the lowest altitude of the LEO satellite.) An advantage of a high-altitude plane over other wireless solutions is that there is almost no interference. Transmitters will be powered with 40 Kilowatts at the 28 and 38 GHz frequency bands. An antenna can receive a signal through trees and during rainstorms. Angel plans to offer three levels of service:
- For home and small business users using dial-up, 1 to 5 Mbps, providing low-cost Internet service, video on demand, and 2-way video conferencing
- For larger businesses using dial-up or dedicated connection, 5 to 12.5 Mbps
- For businesses with dedicated connections, up to 25 Mbps