Last week, the European Space Agency (ESA) announced that two more satellites for Europe’s Galileo
satellite navigation will be launched on 27 March 2015. Galileo satellites 7
and 8 are scheduled to lift off from Europe’s Spaceport in French Guiana on top
of a Soyuz rocket and they are expected to become operational by mid-2015. This
launch, scheduled for late last year, was delayed due to the Soyuz launch anomaly
of Galileo satellites 5 and 6 which took place in August 2014.
Following the launch anomaly, an Independent Enquiry Committee
(IEC) was established by Arianespace to investigate the
exact causes that led to the orbital injection anomaly. On 7 October 2014, the IEC provided its final
conclusions and a set of recommendations.
The Security Accreditation Board of the European GNSS
Agency (GSA), in October 2014, provided its authorization for the repositioning
of the Galileo satellites 5 and 6 in view of their detailed testing.The
repositioning proceeded first with satellite 5, which entered its corrected orbit
at the end of November 2014. This involved raising the lowest point of the
satellite’s orbit more than 3500 km as well as making it more circular. The
test results from Galileo satellite 5 proved positive and the satellite is now
stable and operating in nominal mode.
In March 2015 the sixth satellite reached the
same orbit too. According to ESA, the corrected orbit means that the satellites will
overfly the same location on the ground every 20 days. This compares with a
standard Galileo repeat pattern of every 10 days, helping to synchronize their
grounds tracks with the rest of the constellation.
The European Commission has now to decide what would
be the future use of Galileo satellites 5 and 6 in the operational system.
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