PARIS — Satellite fleet operator SES of Luxembourg on May 2 said its service providing high-definition satellite television channels to German viewers for a monthly fee after a year’s free trial has converted two-thirds of all initial users into paying customers.

In an early test of what SES is counting on as a new revenue stream, SES Astra’s HD Plus has won over 113,500 subscribers, each paying an annual fee of 50 euros ($74). That is 66 percent of the total number of customers who, between November 2009 and March 2010, signed up for a year of free HD Plus service once they purchased HD Plus cards from retail outlets.

Another 655,000 German customers have purchased the cards and are in the middle of their 12-month free trials. While no guarantee can be made as to how many of these customers will convert to paid subscriptions, SES Astra spokesman Marcus Payer said May 2 that the company believes a two-thirds conversion rate is likely to hold for the future.

HD Plus provides eight free HDTV channels that these SES Astra satellite customers would not ordinarily receive. HD Plus customers do not need to sign a contract, and the service cuts off automatically after 12 months if it is not renewed.

SES Astra plans to extend the HD Plus program lineup this summer by adding Sky Deutschland HDTV channels, which can be received by Sky customers’ existing HD receiver.

Germany has long been known in Europe as a nation that resists pay TV service. SES officials say HD Plus may mean things are changing.

“In a country where the question of whether people are willing to pay for television has been discussed for more than 20 years, the first figures of HD Plus are certainly remarkable,” HD Plus Chief Executive Wilfried Urner said in a May 2 statement. “A conversion rate of 66 percent is clearly above the expectations.”

Industry officials say SES Astra has ordered more than 2 million HD Plus cards from manufacturers, including the 769,000 already sold, in anticipation of future demand.