It's Hard Out There for a Wayward Navigation Satellite

Back in August, the European Space Agency launched two satellites intended to make up part of a global navigation system—but, ironically, they got lost on the way.

The satellites were destined for the Galileo constellation, a European project to create a GPS-style navigation system, but things ​didn't go exactly as planned. They found themselves lower than planned, and in an elliptical rather than circular orbit. It was all a bit of a facepalm moment as far as space launches go.

But today, ESA announced that one of the satellites has now been nudged into a better position and has transmitted its first navigational system. All may not be lost.

The point of the Galile​o mission is to launch a series of satellites to provide a European navigation system comparable to the US's Global Positioning System (GPS) or Russia's Glonass. There were four operational satellites of the planned constellation of 30 already up there when numbers five and six went askew, ending up around 10,000 km below the intended orbit of 23,000 km due to the failur​e of thrusters on the Fregat stage of the Soyuz launcher carrying the satellites up.

"It was impossible to work from this orbit," an ESA official told me over the phone. He explained that the altitude control wouldn't work in such a low orbit as the sensors weren't designed for it, and that the environment posed a risk as the satellite had landed in the Van Allen radiation belt.

But in the past couple of weeks, ESA has carefully nudged satellite number 5 into a better orbit through 11​ manoeuvres. Its perigee—the lowest point of its orbit—is now about 3,500 km higher, and its orbit less elongated.

"We can now implement the in-orbit test that helps us to demonstrate that the new series of satellites is working well for the payload part," the ESA official told me, adding that the recovery gives them confidence for future stages in the mission.

The satellite still won't work exactly as planned—it didn't have enough energy to reach the intended orbit—but at least the payload can be used. "From this orbit we are confident we could use this satellite for operational use," he said. It would be down to the system to manage the satellite in its orbit so users on the ground wouldn't notice the difference.

ESA explains that the satellite will now fly over the same spot on Earth every 20 days. "This compares to a normal Galileo repeat pattern of every 10 days, effectively synchronising its ground track with the rest of the Galileo constellation," the agen​cy said in a release.

If tests go well, ESA will turn its attention to the sixth satellite, which was number five's travel buddy and is still in the original wrong orbit, and do the same for it.

The anomaly has set the Galileo mission back a bit, and the next two satellites, which were planned to lau​nch this month, will have to wait until 2015.

The ESA spokesperson said the agency was confident the same problem would not happen again, as the anomaly was analysed by an independe​nt inquiry board and the issues carefully checked in collaboration with Arianespace, which launched the satellites. There will be other Soyuz-Fregat launches before the next Galileo satellites.

At least the last two satellites will, fingers crossed, be operational in their new home—that would have been some very expensive space junk.