A European navigation spacecraft was shot into space this morning, signaling the birth of the continent's Galileo satellite system that will give millions of users access to the most precise positioning data on the public market.

Called GIOVE-A, the first of two test platforms for the project was launched by a Soyuz rocket at 0519 GMT (12:19 a.m. EST) from pad six at snowy Baikonur Cosmodrome in Kazakhstan.

The Fregat upper stage fitted atop the Soyuz three-stage core fired three times to reach a circular orbit -- targeted to be 14,429 miles high with an expected inclination of 56 degrees. The 1,327-pound payload was deployed into space three hours and 42 minutes after liftoff.

An artist's impression of GIOVE A orbiting in space. Credit: ESA

As the first member of the Galileo In-Orbit Validation Element, the satellite launched today will pave the way for the constellation that will one day include 30 satellites regularly flying over most parts of the populated world. The more than $4 billion Galileo system will be operated by civilians for civilians, a significant change from the other two heavyweights in space navigation -- the U.S. Global Positioning System and Russian GLONASS fleet -- both of which are controlled by each nation's military.

The spacecraft was built by Surrey Space Technology Limited of the United Kingdom, and will carry out a two-year mission to test the navigation signals and atomic clock that are at the heart of the Galileo system, and also to secure frequencies assigned to Europe by the International Telecommunications Union to avoid possible interference with the radio waves from the American and Russian systems.

Data from the testbed will also be fed into user receivers to test their capabilities, while sensors aboard the spacecraft will study the high radiation environment the fleet will encounter in their orbits around Earth.

An arrangement of L-band antennas on the Earth-facing panel of the satellite bus and the signal-generation units comprise the navigation payload of GIOVE-A. A pair of rubidium atomic clocks works to ensure precise timing information is relayed to users.

Development of GIOVE-A by Surrey began in July 2003 as the definition phase of the Galileo program was being concluded by the joint team of European Space Agency and European Commission officials managing the project. Teams outlined a space-based navigation system that included a total of 30 operational satellites spread equally among three orbital planes that will ensure all parts of the globe inside of 75 degrees North and South latitude will be adequately covered by the new system.

An artist's concpet depicts the Galileo satellite constellation. Credit: ESA-J. Huart

GIOVE-A will be followed next year by the launch of a second experimental craft called GIOVE-B, manufactured by the Galileo Industries consortium made up of Alcatel Space, Alenia Spazio and Astrium. The second satellite will be able to transmit signals through three channels simultaneously, while the pioneer of the group has the ability to use two channels at once.

Next, the first four operational members of the fleet will be put into space by 2008 to examine the system as a whole group before moving on with the launch of the final 26 satellites, a process due to be complete by about 2010.

Although Galileo and the U.S. Global Positioning System have a formal cooperative agreement to guarantee full compatibility between the two structures, European officials tout the care taken in the design of Galileo to cater to private sector that was unavailable in the military operating scheme the American GPS works in. The European counterpart also broadcasts signals to higher latitudes than the GPS satellites can reach.

Despite this competitive rhetoric, it is well understood that the two groups will offer a similar product, and alternative sources for this critical information provides both Americans and Europeans with greater flexibility. Users should be able to obtain signals from both systems with a single receiver, further exemplifying that the systems are in step with one another.

The U.S. government pressured European leaders during the early stages of development of the system due to worries the new satellites would interfere with frequencies from GPS spacecraft being used by American military forces. A deal between the United States and the European Union was struck in 2004, ending the dispute and clearing the final potential hurdle before full-scale construction and operations could get underway.

The agreement also made the difference between the two fleets almost non-existent from the eyes of a civilian user.

An artist's impression of GIOVE A orbiting in space. Credit: ESA

Galileo will offer four different types of service packages, including an open service that is provided at no cost to users, a safety-of-life service that alerts users when accuracy or integrity is compromised, a commercial service using encrypted signals, and a public regulated service that is aimed at government users.

The cutting edge satellites will collectively pinpoint ground receivers within three feet of their actual location, with some modes able to reach an unprecedented accuracy of just four inches at times.