Europe's Galileo space-based navigation system took another step toward fruition with the launch of a second prototype satellite Saturday night, less than a week after the European Parliament approved plans to finance the network with public funds.

The second Galileo In-Orbit Validation Element, or GIOVE, satellite will test flight hardware for engineers developing the system's operational constellation for launches beginning in 2010.

GIOVE B rode into orbit on a Soyuz rocket topped with a Fregat upper stage. Liftoff of the four-stage rocket was at 2216 GMT (6:16 p.m. EDT), or in the predawn hours of Sunday at the Baikonur Cosmodrome launch site.

The Soyuz flew into a star-filled night sky, shedding its four liquid-fueled boosters and two core stages during the first eight minutes of flight. Fueled by storable propellants, the Fregat fired its engine for about 20 seconds to park the stage and the GIOVE B payload in a temporary low-altitude orbit at about 2226 GMT (6:26 p.m. EDT).

Two more Fregat engine firings are on tap during the next few hours to guide GIOVE B to a circular 14,429-mile-high orbit with an inclination of 56 degrees.

Separation of the 1,104-pound satellite from the Fregat upper stage is scheduled for 0201 GMT Sunday (10:01 p.m. EDT Saturday), followed by deployment of the spacecraft's two solar panels about 30 minutes later.

"We are all looking forward to a successful trajectory of this Soyuz and Fregat, and we are preparing actually for the real operations that will start only a few hours from now," said Javier Benedicto, the European Space Agency's Galileo program manager.

The GIOVE B satellite launched Saturday will pave the way for the 2010 launch of the first four members of Galileo's operational fleet. Subsequent launches through the end of 2013 will fill out the final constellation, which will consist of 27 active satellites and three spacecraft in reserve.

The satellites will be spread among three orbital planes inclined 56 degrees to the equator. The design will ensure full coverage of Europe and nearly all of the world's population.

The system will provide a free service open to all users, plus additional encrypted channels for commercial and government customers.

After a public-private partnership designed to split Galileo's costs between European governments and a private syndicate fell apart last year, the European Commission revamped the program in September to build the satellite network using public funding.

The overhauled program includes a new security oversight authority and procurement rules. The guidelines requires officials to split the network's contracts into six packages for engineering support, satellites, launchers, operations, ground control, and ground infrastructure.

The European Parliament voted Wednesday to overwhelmingly approve the new plan, which will cost European taxpayers more than $5 billion through 2013. The vote was one of the final obstacles standing in the way of full-scale development of the Galileo system.

But first engineers must use GIOVE B and a precursor satellite launched in 2005 to demonstrate the navigation payload before the instruments are launched aboard operational Galileo spacecraft.

European officials selected competing contractors for the two testbed satellites. U.K.-based Surrey Satellite Technology Ltd. was the lead contractor for the GIOVE A satellite, and a team of EADS Astrium, Thales Alenia Space and Telespazio won the spacecraft, payload and operations contracts for GIOVE B.

Now operating nearly four months beyond its two-year design lifetime, GIOVE A has transmitted Galileo navigation signals in two channels since early 2006 to preserve European rights to radio frequencies planned for use by Galileo. GIOVE B will improve that capability to three channels and maintain European access to Galileo frequencies until operational satellites begin launching in 2010.

GIOVE B carries the most accurate clock ever flown in space, using the predictable activity of hydrogen atoms to keep time a billion times more accurately than a digital wristwatch. Galileo satellites need to know the exact time to provide correct position data to users.

The hydrogen maser clock will keep time within one nanosecond per day, or about one second every 2.7 million years, according to ESA.

The launch of GIOVE B was postponed nearly two years due to a serious technical glitch that occurred during ground testing, damaging the satellite's computer. The mission was pushed back again from December because Soyuz rocket parts were not available, according to ESA officials.

The delays forced ESA to sign a contract in March 2007 with SSTL, the builder of GIOVE A, to manufacture a nearly identical spacecraft to fill a potential operations void between the two previously planned Galileo demonstration satellites.

Named GIOVE A2, the replacement satellite was primarily a backup in case GIOVE B was delayed further or suffered a launch failure. ESA's future plans for the satellite are unclear, and attempts to reach agency officials on the matter were unsuccessful.

Engineers used the extra time to install equipment on GIOVE B to transmit a collaborative signal to be employed by the Galileo program and the future U.S. GPS 3A satellite system. The craft will test the signal - called MBOC - to make sure it works as expected.

Plans call for civilian terminals to receive the MBOC signal, allowing users to receive signals from the Galileo and GPS satellites using a single handheld receiver. The cooperative signal will improve accuracy, especially in environments with radio noise and interference.

The U.S. GPS constellation is the only satellite navigation system currently available worldwide. Russia's Glonass network, now only covering domestic users, could be restored to global service by the end of next year, according to Russian officials.

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