Motorola Inc. plans to develop a network of 77 small satellites that would bring cellular telephone service to any point on the globe.

According to executives familiar with the project, known as Iridium, the $2.3 billion system would be financed and launched in the mid-'90s by an international consortium that Motorola hopes to organize. Announcement of the plan is expected to be made today in New York.

Subscribers would talk into small, hand-held units that would be linked by radio waves to satellites circling 413 miles up -- a relatively low orbit for communications satellites. Calls would be relayed from satellite to satellite and down to the ground to reach the other party, who would have to have compatible equipment.

At about $3 per minute and $3,000 per handset, the talk would be far too costly to compete with the conventional cellular systems in use in American cities today. But Motorola executives expect that the system, with a truly global reach, could still find a ready market.

"The mass use will be in sparsely populated areas or in areas of the world such as underdeveloped countries that do not have good mobile telephone service today," said John Mitchell, vice chairman of the Schaumburg, Ill.-based electronics giant. Governments might use the system to keep in touch with remote villages, he suggested, or companies to communicate with oil rigs.

Three major satellite companies have signed agreements with Motorola for joint study of the concept: Inmarsat, the London-based international consortium that provides satellite links to ships at sea; American Mobile Satellite Consortium of Washington; and Telesat Mobile of Canada.

Industry analysts said major hurdles involving technology, regulation and money stand in the way of a satellite cellular system -- an idea that has been proposed by a number of other companies. Scott Chase, editor of trade publication Via Satellite, questioned whether the system made economic sense. Richard DalBello, head of the Commerce Department's office of space commerce, said that many competitors would fight for the scarce radio frequency the system would need.

"It's a very bold scheme, {but} very demanding," said Olof Lundberg, managing director of Inmarsat.

In view of Motorola's vast financial resources -- its sales last year were almost $10 billion -- and expertise in cellular and space technology, however, the industry is paying close attention.

As described by Motorola, the satellites would weigh only about 700 pounds. They might be launched a half-dozen or more at once, maneuvering to separate orbits after their release in space. Two would go up in 1992 to "prove" the concept, with the full system aloft by the end of 1996.

Since the mid-1960s, large satellites in orbits so high that they seem to float above a single spot on the earth have been used widely to channel communications to and from large dishes at fixed locations on the Earth.

Adapting them to "mobile" callers in cars, airplanes or on foot, however, has proved difficult, in part because the ground units must be large and electrically powerful enough to send out signals that can reach satellites so far up.

Inmarsat has about 1,000 portable phones in use but they are bulky, suitcase-sized things with antennae that must be set up. Two U.S. companies have begun using satellites to let dispatchers keep in touch with long-distance trucks, trains and boats -- but only by keyboard.