PARIS — Europe’s first two Galileo navigation satellites have reached their final operating orbits in preparation for activating and testing their navigation payloads, the European Space Agency (ESA) announced Nov. 4.
Marking the formal end of their launch and early operations phase, control of the satellites was passed on Nov. 3 from the CNES French space agency center in Toulouse to the Galileo Control Center in Oberpfaffenhofen, Germany. Oberfaffenhofen, operated by the German aerospace center DLR, will manage command and control of the satellites during their 12-year operational life.
Launched Oct. 21 atop a Russian Soyuz rocket from the new European space center in Kourou, French Guiana, the twin Galileo satellites reached their planned 23,222-km (14,430-mi.) orbit about 3 hr. and 49 min. into the mission. ESA says the first signals were heard almost simultaneously, confirming both satellites are in good health, albeit tumbling through space. The satellites’ solar arrays were deployed once the spacecraft were brought under control.
“Once the reaction wheels steadied them, the satellites sought the Sun and began recharging their batteries, around 70 min. after separation,” ESA says. “The thrusters were then tested—an important milestone because the Fregat [space tug] had carried them most of the way into space but they would have to maneuver the last 100 km or so into their planned final orbits by themselves.”
The satellites then shifted to face the Earth, using infrared detectors, and the Toulouse center commanded a series of thruster firings to nudge the satellites into their intended orbits inclined at 56 deg.
With launch and early operations complete, ground controllers began encrypting telemetry and telecommand links to ensure secure satellite control.
“The next few days will see the navigation payload being switched on, marking the start of Galileo’s In-Orbit Test campaign,” the release says, while a rigorous check of the satellites’ navigation signals is being conducted from ESA’s ground station in Redu, Belgium.
Once the navigation payload is fully checked-out and activated, a second Galileo Control Center in Fucino, Italy, that is operated by Telespazio will oversee all navigation services.