ROME — Mobile satellite services provider Globalstar expects its first six second-generation satellites to be launched aboard a Russian Soyuz rocket in September, with a second six-satellite launch to occur in December or early in 2011, officials from Globalstar and its satellite and rocket providers said here Jan. 27.
Milpitas, Calif.-based Globalstar, whose current 46-satellite constellation is suffering from suspected radiation-caused degradation to its two-way voice service, said two more six-satellite launches of Soyuz rockets from Russia’s Baikonur Cosmodrome in Kazakhstan are scheduled for 2011.
These four launches will complete the set of 24 second-generation satellites for which Globalstar has secured financing. Officials said the company’s banking consortium will await initial revenue results from these spacecraft before agreeing to finance construction of the remaining 24 satellites.
Globalstar and its satellite prime contractor, Thales Alenia Space of France and Italy, have negotiated contract terms for the full 48-satellite constellation.
Addressing a press briefing here, Anthony J. Navarra, president of the company’s global operations, said the full suite of second-generation Globalstar features, including data-transmission speeds of up to 256 kilobits per second compared with the 9.6 kilobits available today, will await further upgrades to the network’s ground infrastructure in 2012.
The second-generation satellites are taking shape at Thales Alenia Space’s satellite-assembly facility here. The first batch of six satellites is scheduled to be shipped to the Baikonur launch site in July.
Once they are launched, Globalstar will take several weeks to test the spacecraft in orbit. Globalstar’s insurance underwriters are insisting on proof that the spacecraft — which represent a substantial design change from the first-generation satellites — function as planned before more are launched.
Navarra and Rene Serret, Thales Alenia Space’s Globalstar project manager, said the new satellites feature radiation-hardened components and a design that places sensitive gear well inside the satellite’s frame to help shield it from the radiation environment in Globalstar’s operating orbit of 1,414 kilometers.
“Almost all the satellites’ vital functions are redundant,” Serret said, meaning each satellite carries backup units of the critical components. He said that the company has designed the radiation-sensitive parts with sufficient safety margin to ensure they will function under exposure to radiation substantially higher than that expected in orbit.
These and other improvements have doubled the contracted service life of the second-generation satellites to 15 years compared with 7.5 years for the first generation. The improvements have also sharply increased the launch weight, from 550 kilograms for the first-generation satellites to 700 kilograms for the second generation.
Navarra said 20 of Globalstar’s satellites currently in orbit, including eight that were launched in 2007 — the rest were launched between 1998 and 2000 —continue to make use of their two-way communications capability.
By placing the first 24 second-generation satellites in areas needed to fill gaps in voice communications, Globalstar expects to be able to return to full two-way capability well before the second batch of 24 satellites is launched sometime after 2011.
Globalstar’s nominal 48-satellite constellation consists of six satellites in each of eight orbital planes.
Alex Mademba-Sy, Globalstar project manager at the Arianespace launch consortium of Evry, France — which, through its Starsem affiliate, commercializes Soyuz rockets from Baikonur — said a newly designed dispenser will carry the six second-generation Globalstar spacecraft into orbit under the payload fairing of the Soyuz-Fregat rocket.
The dispenser, built by Astrium Space Transportation of Les Mureaux, France, completed testing in December. A final flight-qualification review is scheduled for February, Mademba-Sy said. The Baikonur launch pad that will host the Globalstar launches rarely has been used in the past couple of years and will require maintenance work scheduled between April and June, he said.
Navarra said an upgrade of Globalstar’s seven gateway Earth stations that control the constellation is expected to be completed by June.
