Two Galileo Satellites Are Parked In the Wrong Spots

Did a software error in a Soyuz rocket cause their errant placement?

3 min read
Two Galileo Satellites Are Parked In the Wrong Spots
Illustration: ESA

On 22 August, a Soyuz rocket launched the fifth and sixth satellites of Europe's Galileo project, a satellite navigation system that will eventually comprise 30 satellites designed to make Europe independent of U.S., Russian, and other GPS systems. Unlike most Soyuz launches, the rocket did not lift off from Baikonur, Kazakhstan, but from Kourou, Europe's space center in French Guiana.  Apparently the launch went off without incident, but it soon became apparent that the two satellites were injected into the wrong orbits. The upper stage of the Soyuz rocket, the Fregat-MT, injected them into elliptical orbits instead of circular ones, making the satellites unusable for GPS navigation.

Initially, blame fell on the Fregat-MT’s outdated navigation system, or on the possibility that its engine malfunctioned. Kourou ground crews dealing with an unfamiliar launcher was also viewed as a possible cause. But it has since been confirmed that the crew that readied the Soyuz for launch was a Russian team. The Izvestia reported on Thursday that according to Roscosmos, the Russian Space Agency, it was likely that a software error caused the two Galileo satellites to be placed in the wrong spots. If true, it would follow on the heels of a software error earlier this year that left the Russian navigation system GLONASS out of commission for 11 hours. The Izvestia article added that software development is a weak spot for Roscosmos because of chronic underfunding.

The October 2011 launch of the first four Galileo satellites—experimental satellites to validate whether the Galileo technology actually worked in space—by Soyuz launchers was a complete success. But it was also the first time that Soyuz launchers were used outside Russia or Kazakhstan. A 28 August article in Le Monde, takes its headline, "We Would Have Done Better by Launching With Ariane," from a quote attributed to the French Coordinator of Galileo, Jean-Yves Le Gall, president of CNES, the French Space Agency.

European Space Agency spokesperson Dominique Detain disagrees: "For the early launches we needed only a middle-class launcher. The first satellites were light, and it made no sense to launch them with an Ariane 5," he told IEEE Spectrum. And the reliability of the Soyuz launchers is high. "They have the best record ever, with 1800 successful launches; and Fregat has been successful for over four years," says Detain.

There is a lot of speculation about how the project will go forward. The two satellites were intended to be part of the actual operational system of 22 satellites, but being in the wrong orbits makes this now impossible. The hydrogen fuel aboard the satellites allows for small orbit corrections, but is insufficient for the drastic orbit change that would be required to make them fully operational.

Le Gall would prefer to switch to Ariane right away, and he believes that this is what will happen, as reports Le Monde.  However this will require an extensive reorganization of the project. According to current plans, six more Soyuz will launch 12 satellites, and the remaining 12 satellites will be placed in orbit by three Ariane 5 launchers.

ESA set up an international inquiry board to ascertain what went wrong during the launch; the group will issue a report on 8 September, says Detain. "They are discussing how to rescue as much as possible of this mission, in a way to make it a "technology" mission," says Detain.  For example, one of the possibilities would be to reprogram the two satellites so that they can operate from a wrong orbit, but this will also require reprogramming the ground segment.  "It will take weeks before we make a decision," concludes Detain. 

The $7.2 billion Galileo project has now seen six years of delays and it is clear that whatever will be done to fix the latest problem will add substantially to this delay.

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