PARIS — A telemetry failure during the otherwise successful Dec. 18 launch of a Europeanized Soyuz rocket — the second consecutive malfunction of the rocket’s upper stage during launch — raises questions about whether European governments will trust the vehicle to launch Europe’s Galileo positioning, navigation and timing constellation, European government and industry officials said.

A Europeanized Soyuz placed two Galileo satellites into a bad orbit in August, a glitch that was later traced to insufficient precision in the Fregat upper stage’s design manual that led its builders to place helium and hydrazine fuel lines too close together.

The rocket returned to flight Dec. 18 with the launch of four satellites for O3b Networks’ Ka-band Internet trunking service.

In this case, the satellites were placed into the correct orbit and are healthy. But sometime after the second of two ignitions of the Fregat upper stage, the stage stopped sending telemetry to ground controllers.

As is habitual with the Europeanized Soyuz, data are sent from ground stations — in this case, in Hawaii — directly to Fregat manufacturer Lavochkin of Moscow and then relayed to ground controllers at Europe’s Guiana Space Center in French Guiana, on South America’s northeast coast.

The final 40 minutes of the O3b mission were spent in the dark, with the broadcast produced by launch service provider Arianespace of Evry, France, relying on mission simulation videos to explain where Fregat was thought to be, and what it was supposed to be doing, without confirmation that the stage was performing as expected.

The tension ended when the first two O3b satellites were released, apparently at the expected time and place, and began sending information on their own. The two other satellites followed several minutes later and they, too, confirmed their health.

Arianespace officials, who had been embarrassed in August when they and their customer broke out Champagne to toast a launch success that turned out otherwise, waited for a couple of hours before confirming that the O3b satellites were healthy and in the right location.

Arianespace is managing the review of the December anomaly with Lavochkin.

The 20-nation European Space Agency and the European Commission, which is the executive arm of the 28-nation European Union, are in charge of the Galileo program, with the commission having final say as Galileo’s owner.

The independent board of inquiry established after the August failure produced a Fregat to-do list that Arianespace Chief Executive Stephane Israel said was divided into two parts. The first covered Fregat procedures deemed necessary for the vehicle to return to flight. This, he said, was accomplished and paved the way for the Dec. 18 mission.

The second part of the inquiry board’s recommendations deals with longer-term Fregat quality assurance procedures. Israel said these corrective measures would be put into place in time for a March launch of two Galileo satellites.

But ESA and the European Commission have not yet signaled their readiness to return to Soyuz. They have the option of using a heavy-lift Ariane 5 rocket, carrying four Galileo satellites per launch, in late 2015.

Israel said it will take until then to qualify the Galileo satellites, built by OHB AG of Bremen, Germany, for the environment they will encounter under the Ariane 5 fairing at launch.

ESA Director-General Jean-Jacques Dordain on Jan. 16 said the agency was still sifting through information about the December Fregat anomaly and because of that had not given the European Commission the ESA view on whether the next Galileo mission should be aboard a Soyuz in March.

Dordain said ESA, as the commission’s technical adviser, would deliver its conclusions to the commission the week of Jan. 19, and the commission would then decide its Galileo launch strategy by the end of the month.

Speaking at a space policy conference here two days earlier, Dordain said the OHB team has two Galileo satellites that are ready to launch — those that Arianespace has penciled in for March. Two others would be ready in short order and another pair will be ready toward the end of the year, Dordain said.

Arianespace has a full manifest of Ariane 5 launches this year, with six or seven missions planned in addition to two Soyuz launches and three missions of Europe’s Vega small-satellite launcher. But Israel, in a Jan. 6 briefing, said Arianespace was ready to do whatever the commission asked of it to assure timely in-orbit delivery of Galileo.

Even before the Dec. 18 anomaly, industry and government officials had described the commission as deeply shaken by the August failure. But scrapping Soyuz would mean incurring near-term costs of qualifying the satellites for the Ariane 5, a process that would require that two Galileo satellites be taken out of the launch queue for vibration and other testing. For that to happen, contracts must be let with industry to perform the qualification work. One industry official said this has not yet happened.