Two Washington public relations men are about to launch an out-of-this-world plan that for the first time will use earth satellites to distribute press releases to broadcasters throughout the country.

Called PubSat--for Public Relations Satellite System Inc.--the venture is scheduled to go on the air Jan. 19, piggybacking on a satellite serving the 236 radio stations in the National Public Radio network.

Negotiations are underway to expand the service to at least 1,100 other radio stations and then to television, said Tom Tucker of Tucker-Roberts Associates in Washington.

The plan was developed by Tucker and John Sullivan of Falls Church, who produces and distributes public service announcements to radio stations.

Their PubSat plan is patterned after Western Union's Public Relations News wire service, which distributes news releases to about 150 newspapers.

Instead of printed statements, however, the new system will distribute prerecorded radio material, ranging from 55-second spots to longer features, Sullivan explained.

"If General Motors has somebody testifying on the Hill about pollution controls and they want to get the word out, we can do it," said Tucker.

At present, Sullivan added, corporations, trade associations and political groups trying to get material to radio stations use either the telephone or the mail. "The mail takes forever and telephones cost a bundle."

To offer radio stations a recorded comment or statement now, Sullivan said, it's necessary to call stations individually, explain what's available, then play the tape.

The two said their recently organized venture has signed an agreement with National Public Radio to sublease, in effect, 15 minutes of time on the Westar satellite that distributes NPR programs. NPR will provide the "uplink" sending messages to the satellite.

Tucker said one major public relations firm, Burson-Marsteller, has agreed to try the service for its clients, and others are interested, including Gray & Co.

Sullivan stressed that the service will offer stations public affairs material with news value, not routine announcements of thinly-disguised plugs for a particular firm.

Tucker said the initial charge for the service will be $300 for a one-minute spot.