who wish to reduce the number of devices they must carry with them in order to stay connected. ORBCOMM ORBCOMM is a partnership jointly owned by Orbital Sciences Corpora- tion and Teleglobe Canada. Their satellites are nothing more than extraterrestrial routers which interconnect vehicles and Earth stations to facilitate deployment of such packet-based applications as two-way short messaging, e-mail, and vehicle tracking. Their constellation has a total of 35 satellites. Angel Technologies Angel Technologies uses a different technique, flying airplanes above metropolitan areas that provide 10 Mbps symmetrical Internet access. In the United States, Angel's services operate in the LMDS microwave ranges of 24 GHz, 28 GHz, and 38 GHz. In other countries, the 3 to 20GHz range will be employed. The airplane is similar to a corporate jet; it flies 10 miles above the target area in a 2.5-mile-diameter circle, offer- ing a service footprint of up to 75 miles. The planes fly three shifts of eight hours each; the 40-kilowatt signal they generate is powered by the aircraft's engines and can penetrate weather conditions that are nor- mally bad for microwaves. Angel is working closely with Raytheon Corporation to develop the communication link, and with a variety of companies that have pio- neered high-flying, long-duration aircraft. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Access Technologies Access Technologies Satellite Services: What's the Catch? As a service provisioning technology, satellites may seem so far out (no pun intended) that they may not appear to pose a threat to more tradi- tional telecommunications solutions. At one time, that is, before the advent of LEO technology, this was largely true. Geosynchronous satel- lites were extremely expensive, offered low bit rates, and suffered from serious latency that was unacceptable for many 