Mobile satellite services provider Globalstar launched its fourth and final batch of six second-generation telecommunications satellites Feb. 6 atop a Russian Soyuz launch vehicle from the Baikonur Cosmodrome in Kazakhstan.

Evry, France-based Arianespace and its Russian Starsem affiliate said the launcher’s Fregat orbital stage accurately injected the six spacecraft into their target orbit shortly after liftoff at 10:04 p.m. local time.

“Two successive firings of the Fregat stage were needed to carry out this mission,” Arianespace said in a Feb. 6 statement. “After stabilization of the stage, the dispenser released one hour and 38 minutes after liftoff the two satellites positioned in its upper section; one minute and 40 seconds later, the four satellites in the lower part of the dispenser were released simultaneously.”

The Thales Alenia Space-built Globalstar satellites weighed roughly 650 kg (1,430 lb.) each at launch. The first 18 satellites of the Globalstar second-generation constellation were orbited successfully by Arianespace and Starsem in 2010 and 2011.

Since 2007, when the bulk of Globalstar’s first-generation satellites launched in the late 1990s began degrading in orbit, the fleet operator has lost customers in droves — first to chief competitors Iridium Communications and United Arab Emirates-based Thuraya, and ultimately to Inmarsat, which in 2010 brought its first hand-held satellite phone to the small but growing global market for two-way satellite voice communications.

After repeated delays in putting a new constellation into orbit, the company is poised to rebound in 2013 with all 24 spacecraft now in orbit, and with eight first-generation satellites launched in 2007 that continue to function nominally.