The Reagan administration sent an impartial observer to Intelsat's board meeting last week to make sure the U.S. signatory to the global telecommunications consortium, Communications Satellite Corp., represents the interests of the U.S. government.

This is the first time a U.S. observer has been sent to a "board of governors" meeting where 27 governors representing 90 out of the consortium's 109 member nations meet to discuss business, the paper Communications Daily reported.

The Washington-based, 21-year-old International Telecommunications Satellite Organization provides telephone, telex, and television services to most of the world. Comsat, the U.S. signatory to the organization, represents the U.S. government's interests and acts as the gatekeeper to Intelsat for U.S. companies like American Telephone & Telegraph Co., reselling the services Intelsat provides.

A few months ago, President Reagan challenged the virtual monopoly Intelsat has excercised over global satellite services by authorizing separate international satellite systems. The Commerce Department has also asked the Federal Communications Commission to grant companies direct access to Intelsat, bypassing Comsat altogether, in an effort to bring down prices for satellite services and keep the consortium competitive.

Until now, the U.S. government has been pleased with Comsat's "pretty good job of representing the government's views," said David J. Markey, assistant secretary of commerce for telecommunications and information policy.

But, "as competition has raised its ugly head and more parties have become interested in what happens to Intelsat, it has become clear Comsat would have trouble representing its own interests and the interests of the U.S. government," said Markey.

A Comsat spokeswoman said the company has no problem with the FCC, Commerce and State department decision to send an observer to the Intelsat meetings. "Comsat is working in a constructive and cooperative manner with the U.S. government . . . we have worked out an arrangement for this procedure that is acceptable to both Comsat and the three interested government agencies," she said.

Some would-be competitors to Intelsat have said Comsat should not continue representing U.S. views since they conflict with the interests of the company, and congressmen have asked that an observer be sent to make sure President Reagan's directives are followed.

Markey said it has become increasingly difficult for Comsat to represent U.S. interests since President Reagan's decision to authorize separate satellite systems.

The meetings that took place this week discussed how alternative systems would be coordinated with the Intelsat system and whether there would be any guidelines on how the systems would be coordinated.

In the past Intelsat has coordinated other smaller international satellite systems such as Arabsat, the Indonesian Palapa system, and Eutelsat, a regional European satellite system.

"But, several years ago Richard Colino Intelsat director general was instructed by the board of governors to come up with guidelines and they were very restrictive and would have assured that the U.S. would have had no successful coordination" of competitive U.S. systems, said Markey.