THE CUTTING EDGE : Data--or Pie?--in the Sky

Teledesic Corp., backed by high-technology investors Craig McCaw and Bill Gates, recently announced grand plans for a $9-billion satellite network to provide high-speed voice, data and video communications worldwide. Skeptics--and competitors--abound, but here’s how the system is supposed to work for users in a city, a major computer site (a business or university), and a rural home.

The Teledesic network would consist of 840 satellites in orbit at just 430 miles above the earth (unlike most communications satellites, which are at 22,500 miles.) Each one would circle the globe vertically, with 40 satellites in each of 21 paths. Each satellite would take 99 minutes to complete an orbit, and would have an estimated life of 10 years.

1. City A user sends audio, video or text through local phone lines to a high-speed terminal, which encrypts the data and fires it up to the nearest satellite. Computers direct the data onward through other satellites until the closest one to the recipient is found. From there, the signal is beamed down to another high-speed terminal, decoded and sent through phone lines to the recipient.

2. Major computer site Using its own dedicated high-speed terminal, the organization would continually send large amounts of data directly to the satellite network, avoiding phone-line bottlenecks in the process.

3. Remote residence A smaller, slower housetop dish would be available to users in rural or undeveloped areas, where it would obviate phone lines. The dish would require so little electricity that it could probably run on solar power.

Source: Teledesic Corp.