Globalstar Inc. is anticipating a May 21 launch window for the first of its four first-generation ground spare satellites to be lofted, the company announced April 18.

The four satellites, combined with four others due to be launched later in 2007, will be used to bolster the company’s current first-generation LEO (low earth orbit) satellite constellation.

Globalstar is investing more than $110 million in the two launches, to be conducted by the Russian-European launch services company Starsem (Arianespace, Astrium, Roscosmos, Samara Space Center) from the Baikonur Cosmodrome in Kazakhstan. The satellites are to be lofted in Soyuz launches 7 and 8; the Soyuz vehicle successfully launched 24 Globalstar satellites from Baikonur in 1999.

Globalstar plans to use its current constellation plus these additional eight first-generation satellites as it manages the transition through to the launch of the Globalstar 2 second-generation constellation, expected to begin in late 2009.

In February, degraded performance from Globalstar’s constellation of 40 satellites led the company to warn its customers that they may lose two-way voice and data service as early as next year.