Post Tue Jul 19, 2011 9:46 am

Globalstar network moves to phase two

Starsem Company, part of Arianespace, which operates the Soyuz 2-1A rocket from Kazahstan, managed to simultaneously launch six satellites for the U.S. telecom operator Globalstar.
Soyuz 2 is the same rocket that will be operated by the French Guyana, besides Ariane 5 and Vega.
Launched on 19 October, at 17:10 UTC from Baikonur, the rocket managed to inject all of the six satellites onto a transfer orbit with the altitude of 920 km and an inclination of 52 degrees, after a 100 minute flight. From this point, the orbital motors aboard will increase the orbit's height until it reaches the operational orbit – circular orbit 1410 km x 1410 km x 52 degrees.
Placed inside the protective capsule on two levels, two satellites at the top and four at the bottom, the new Globalstar platforms left the launcher one by one, all their signals being received successfully by the Russian ground stations.
The satellites are part of the new generation Globalstar 2 and are built by the Franco-Italian company Thales Alenia Space that signed a contract in 2006, which included 48 platforms and which had a value of 660 million euro, with an average price below 15 million euro per satellite.
Weighting 700 kg, they are equipped with 32 transponders, being able to communicate in L,S and C bands. With the life expectancy of 15 years, the two solar panels generate a minimum of 1.7 kW enough to cover the consumption of energy.
It’s a change from the first generation of Globalstar satellites, which were almost half the weight, i.e. 450 kg. The lightweight allowed the launch of 4 satellites simultaneously with the Soyuz classic board, between 1999 and 2007, Starsem performing 8 flights for Globalstar. These satellites were built by Space Systems and had a life expectancy of 7.5 years.
The flight we’re talking about now is only the first of the four planned for Globalstar 2, a total of 24 satellites will join the network and ensure the continuity of voice and data services until at least 2025.
Repairing the constellation was imperative because communication services have recently suffered from the physical wear of the satellites. Since 2007, because of a decrease in performance of the S-band antennas, the 400,000 users were unable to use voice services and duplex data communication and had to use as an alternative the tools available on the website, in order to calculate the communication windows.
This is clearly an improvisation and a weak point for the American operator, especially because many of the users from the country-side have no other option but satellite communication.
By this time, the constellation covers about 80% of the Earth's territory (excepting remote areas like the poles) and uses CDMA (Code Division Multiple Access) signal technology, any one of the satellites being able to receive calls from its instantaneous coverage area and transmit it over from satellite to satellite until one of the platforms is in the vicinity of a gateway (avoiding in this way ground obstacles; transmission is made possible in remote areas via the spatial segment). Terrestrial transmission points are connected with local voice and data networks, which take the signal and finish the operation.
Unlike the case when geostationary satellites are used, the use of a LEO orbit eliminates the echo effect and the delay of telephone conversations and allows use of smaller handsets.
Globalstar Inc. is a company with customers in over 120 countries, with centers in Covington, Louisiana and Milpitas, California, incorporating Globalstar Mobile Satellite System and Globalstar Gateway Earth Stations as subsidiaries. Beside the spatial segment, the American company also holds a spatial operations command center, SOCC (Satellite Operations Control Center), a network of ground antennas, GDN (Globalstar Data Network), and antenna command center, GOCC (Ground Operations Control Center).
Globalstar Inc. is the successor of Globalstar LLC since March 2006, when the shareholders decided to change the company's name. Globalstar LLC had taken the assets of Globalstar LP, which had declared its financial problems back in 2003 and came under bankruptcy protection, in April 2004. New investments that began in 2006 with an order of 48 satellites are therefore part of a management plan that should boost the company's market value and its long term income.