ESA to launch two navigation satellites this week
The European Space Agency (ESA) says the satellites will blast off on a Russian-made Soyuz rocket from Kourou in French Guiana and should reach orbit at an altitude of about 23,500km in just under four hours. They are expected to be fully operational sometime between September and November.
The Galileo satellite constellation, a rival to the US Global Positioning System and Russia's Glonass, will eventually comprise 27 satellites and three reserves.
The network seeks to provide an alternative in case of signal failure on the existing GPS and Glonass systems.
The first pair of orbiters were launched in October 2011 and the second a year later.
According to ESA, this week's launch, of the first operationally-capable satellites dubbed SAT 5 and SAT 6, had been delayed because of technical difficulties in the setting up of the production line and test tools.
Launch and system delayed
Four satellites were supposed to have been launched last year.
When this did not happen, ESA Director-General Jean-Jacques Dordain said that six satellites would be launched this year, paving the way for initial satellite navigation services to start by the end of the year.
However, ESA now expects to send just one more satellite pair into space before the end of the year.
"Then the constellation will be gradually deployed with six to eight satellites launched per year," it claimed.
According to ESA's website, 18 satellites should be able to provide initial services to users next year, with full services from the 30-part constellation only scheduled for 2019.
In March last year, ESA said Galileo's first four test satellites had pinpointed their first ground location with an accuracy of between 10 and 15 metres.
For its ninth lift-off from the Guiana Space Centre, the Soyuz rocket will carry a total load of 1.6 tons, including the two satellites weighing 730kg each.
Galileo, has budgeted €5.4bn for the project, which is fully financed by the European Commission.
Source: AFP via I-Net Bridge
