First Galileo navigation satellite begins broadcasting
BY STEPHEN CLARK
Posted: December 18, 2011
Engineers are analyzing the first signals from a Galileo navigation satellite after its payload began switching on last week for testing, according to the European Space Agency.
Both satellites launched Oct. 21 from French Guiana aboard a Soyuz rocket.
The test signals were transmitted to Earth for technical evaluation as the European Commision, the EU's executive body, and the European Space Agency sort out how to construct and launch the rest of the 30-satellite Galileo fleet.
The first satellite's E1 navigation signal, one of 10 bands each craft will broadcast, was turned on Dec. 10 and received at ESA's Redu ground station in Belgium, the space agency announced.
The E1 signal will be used for Galileo's open service, which will be available to provide precise positioning and timing data to global users beginning in 2014, according to the European Commission, which oversees the program.
The satellite's E5a and E5b signals were activated Dec. 15.
The rest of the craft's L-band signals will be switched on through the end of 2011, then attention will turn to the identical second satellite in early 2012, ESA officials said.
Other Galileo signals will enable highly-precise encrypted public regulated services, geared for government and military users, commercial services for authenticated professional customers, and a signal to relay distress messages for search-and-rescue missions.
The navigation system activation came slightly ahead of schedule. At the time of the satellites' launch in October, officials said the first signals would be transmitted in January.
The satellites were assembled by Thales Alenia Space of Italy, and EADS Astrium of the United Kingdom provided the navigation payloads.
The first two spacecraft are now in position 14,400 miles high after a series of maneuvers following their launch.
The satellites are part of Galileo's in-orbit validation, or IOV, program to prepare for operational service. Two more IOV satellites are due for liftoff in mid-2012.
Fourteen operational satellites are under construction by OHB System AG of Germany. Those spacecraft are scheduled to begin launching in 2013.
The European Commission is accepting bids from OHB and Astrium Satellites to build six or eight more satellites. Officials expect to select a contractor for the next batch of spacecraft in the first quarter of 2012.