They're alive! Galileo sats 9 and 10 sending valid signals

Two more satellites in Europe's Galileo satellite navigation swarm are up and running, so to speak.

The European Space Agency (ESA) has announced that the ninth and tenth satellites in the planned 30-bird fleet started sending “valid navigation signals” as of January 29th.

Galileo's eleventh and twelfth satellites are also aloft, but are undergoing testing. The ESA says the two satellites have reached their final orbits and that “payload activation is proceeding according to schedule.” Another pair of satellites have completed pre-flight testing and are in storage ahead of launch.

The ESA's plans for Galileo call for a constellation of 30 satellites. Eight birds will be grouped in one of three orbits for a total of 24 operational satellites. Each orbit will also host a pair of backup satellites. Each satellite has an expected working life of a dozen years.

While Galileo has military applications like helping to guide nuclear missiles, it is most-often-mentioned for its civilian navigation applications. While the project has picked orbits that make it fine for European users, it is also interoperable with the United States' GPS and Russia's Glonass systems. ®