One Galileo Back on Track

A European Space Agency (ESA) Galileo satellite that had slipped into an erroneous orbit soon after deployment last August is reportedly back on its feet, so to speak. The unmanned craft sent its first navigation signal in space on Saturday 29 November 2014 after reaching a new target orbit.

This is the fifth of six satellites to start contributing to the ESA's Galileo global positioning (GPS) network. However the sixth satellite remains unaligned and incapable of inter-satellite communication.

Still, this first repositioning is a good start, the ESA reports, as the two wayward satellites were initially in an unpredictable and elongated orbit travelling up to 16,000 miles (25,900 km) above Earth and back down to a mere 8520 miles (13,713 km) - a distance that brings the craft dangerously close to slipping into a gravity-induced spiral back to earth.

Thankfully, despite their poor deployment, the satellite pair are undamaged and fully functional, allowing the fifth Galileo to conduct a total of 11 maneuvers over 17 days that nudged it back up to an safe and circular orbit.

"The manoeuvres were all normal, with excellent performance both in terms of thrust and direction," Daniel Navarro-Reyes, ESA Galileo mission analyst, said in a statement. "The final orbit is as we targeted and is a tribute to the great professionalism of all the teams involved." (Scroll to read on...)

The repositioning commands were a success thanks to the collaborative efforts of the German and French space agencies, and were uploaded to the satellite via an extended network of Galileo ground stations.

Still, it should be noted that this wasn't a perfect recovery. As opposed to the ideal obit that the other four satellites are in,  the fifth Galileo will now fly over the same ground location every 20 days. This compares to a normal Galileo repeat pattern of every 10 days. Now we wait for the ESA to attempt to recover their sixth.

Galileo is no stranger to delays. The project has faced years of delays while sat-nav technologies improved and planning was adjusted. The ESA, which is building the orbital network on behalf of the European Union, expects to have 26 satellites in orbit by 2017.

To date, the project has cost the EU nearly $8 billion (USD).

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