Test craft for Europe's navigation system blasts off
BY STEPHEN CLARK
Posted: April 26, 2008;
Updated after satellite deployed from rocket
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 Russian Soyuz rocket topped with a Fregat upper stage. Liftoff of the four-stage rocket was at 2216 GMT (6:16 p.m. EDT) Saturday, or in the predawn hours 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 about 10 minutes after liftoff.
Two more Fregat engine firings guided 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 occurred at 0201 GMT Sunday (10:01 p.m. EDT Saturday). Deployment of the spacecraft's two solar panels was expected about 30 minutes later.
"We've acquired the signal when it was expected," said Javier Benedicto, the European Space Agency's Galileo program manager. "This is very promising. This means that the orbital parameters of the injection from Soyuz-Fregat are probably nominal."
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.
The early demonstration phase of the program, including GIOVE B, was paid for by ESA and the European Union.
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.
"It's a change of role for ESA because we are no longer the customer," said Jean-Jacques Dordain, ESA director general. "We're the prime contractor, so we're now responsible to our customer, the European Commission, for the development of this constellation with European industry.
The overhauled program includes a new security oversight authority and procurement rules. The guidelines require officials to split the network's contracts into six packages for engineering support, satellites, launchers, operations, ground control, and ground infrastructure.
"We hope that by the end of this year all the procurement contracts will be signed, and European enterprises will be able to develop their capacity to build these satellites, to construct the ground equipment, and to make the system functional," said Jacques Barrot, EU transport commissioner.
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.
"Galileo will give the European Union a necessary independence in the field of satellite navigation. Imagining a Europe dependent one day on an American system, and the next day on a Russian or a Chinese one, is just unthinkable."
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.
With a planned life of more than two years, 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. The Galileo operational fleet will use the same clock to determine the exact time to provide correct position data for 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.
"With the technologies we have developed, we have full confidence that the Galileo system can be deployed on time, meeting the expectations of users and meeting also a very high level of performance and range of services," Benedicto said.
ESA also manages a program to sharpen the accuracy of signals from the U.S. Global Positioning System for improved air and sea traffic safety. The EGNOS program uses information on the reliability of navigation signals to increase the accuracy of the GPS network tenfold.
"Although we're only at the start of the deployment of the constellation, we have been working on satellite navigation with the EGNOS system for 10 years," Dordain said. "EGNOS offers an improvement of the GPS system over Europe and works very well."
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 to transmit a collaborative signal to be employed by the Galileo program and the future U.S. GPS 3A satellite system. GIOVE B 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.
"We're not building Galileo as some sort of competition to American GPS, but as its twin brother, allowing Europe to have its own signal, which is also to the advantage of our friends on the other side of the Atlantic," Barrot said.
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.