KOUROU, French Guiana (AP) _ A West German telecommunications satellite failed to deploy one of its two solar panels Saturday, hours after being placed into orbit in a perfect launch by Europe's Ariane rocket, officials said.

French Premier Jacques Chirac praised the performance of the 20th Ariane mission as ''a symbol of European efficacy'' while a West German official said the solar panel problem on the TV-SAT1 satellite was ''not dramatic.''

TV-SAT1 was placed in transfer orbit Friday night 19 minutes after the late night liftoff of the Ariane 2 rocket from its South American jungle base.

It was the Ariane program's second successful launch following a 16-month hiatus in which all rockets were grounded due to technical problems.

The launch appeared to confirm Ariane as the West's only regular satellite launcher in the lucrative market of putting commercial satellites into space.

West German technicians in Kourou did not appear upset by the satellite's performance.

Andreas Langemeyer, head of the TV-SAT project for the West German government, told reporters maneuvers could be attempted in space to get the panel into place.

''The situation is not dramatic at all,'' said Langemeyer. ''It is simply abnormal. A team of engineers is studying the problem. Nothing is lost.''

He noted that the two solar panels are not to be completely deployed until the satellite reaches its definitive orbit at 22,500 miles - in about 24 days.

Technicians, therefore, have time to right the faulty panel, he said.

Gerhard Korner, director of the French-German consortium Eurosatellite which built the TV-SAT1, said a similar problem years ago was straightened out in about two weeks.

''At worst, if we do not succeed in deploying the panel, the satellite could still function, but with half its power, therefore with half of its television channels,'' Korner said.

TV-SAT1, which will serve four television channels, is to provide what is being billed as the highest quality image to up to 300 million viewers around Europe. It is to go on line early next year.

The cost of launching the $108 million TV-SAT1 was $97 million. The satellite is expected to last for 10 years.

''We have here one more proof that man is not master of everything,'' Korner said.

Frederic d'Allest, president of Arianespace, the commercial arm of the European Space Agency, said the launch itself went perfectly.

''It's a great satisfaction,'' he added.

The Ariane program was restarted Sept. 16 when the 19th launch placed European and Australian communications satellites into orbit. The National Aeronautics and Space Administration program in the United States, Ariane's chief competitor, was halted after the January 1986 explosion of the space shuttle Challenger. The United States has reverted to conventional rocket launchers like Ariane, but has not been launching satellites regularly.

Both the Soviet Union and China have satellite launchers and both countries have expressed an interest in launching Western satellites. A Houston-based firm is negotiating with the Soviet Union on behalf of some American companies for the Soviets to launch American satellites. China's Long March rocket has launched some Western satellites over the past two years.

Arianespace announced Saturday that its next launch, using the more powerful Ariane 3 rocket with a two-satellite payload, would be early next year but it did not set a date. It said the rocket would place in orbit the American Spacenet III R/Geostar RO1 satellite and the French Telecom IC.

A launch originally scheduled for December was recently postponed. Nine launches are planned for 1988 and nine more for 1989.

Arianespace said it has 43 more firm satellite launch orders worth an estimated $2.37 billion.