Iridium Satellite, which uses low-orbiting satellites to offer global mobile phone coverage, also hopes to go public sometime next year.

Professor Negroponte believes that if plans to launch low-orbiting satellites are realized, "my communications reach is worldwide, with or without national phone systems."

An eavesdropping craft remains in such a geostationary orbit, unlike low-orbiting photographic satellites that move over much of the earth's surface.

For instance, he said that because of the low-orbiting satellites, Iridium "is the only system that can provide service to a small handset."

They do not rely on equipment on the ground because they beam their signals to low-orbiting satellites.

But one of the big innovations of recent years has been the low-orbiting satellite.

The Navy also is asking for $94.6 million in 1990 to see if a laser could be mounted on shipboard to knock out low-orbiting satellites.

An agreement that would allocate global radio frequencies for fleets of low-orbiting satellites serving portable telephone and message services has been reached.

Globalstar plans to provide telephone service by bouncing signals off 48 low-orbiting satellites.

An additional risk is posed by (unmanned) low-orbiting satellites whose orbits eventually decay due to friction with the extremely thin atmosphere.