WASHINGTON (MARCH 16) AP - An American communications satellite that was launched last week has rocketed into geosynchronous orbit and should start operating early in April. The Spacenet III satellite owned by GTE Corp. was launched Friday night by a French Ariane rocket. On Tuesday, the satellite fired its apogee kick motor, a small rocket engine, and moved into orbit 22,300 miles above the equator, GTE officials said. Since the satellite is moving at the same rate of speed as the earth, it will in effect hover over a point on the earth's surface. The 1,562-pound satellite provides a communications link between points in all 50 of the United States. Clients include The Associated Press and the television groups of ABC, CBS, CNN and Gannett. The U.S. satellite and a French communications satellite were launched together Friday from the European Space Agency launch site in Kourou, French Guiana. GTE Spacenet is the first American client of Arianespace, the operating arm of the European Space Agency.