The launch of the first two satellites for Europe's Galileo navigation system was on Thursday postponed due to "technical reasons."
Galileo is Europe's 5.4 billion-euro "more precise" rival to the global positioning system in the United States.
Two spacecraft had been due to ride a Soyuz rocket that was to take off from Europe's space base, in French Guiana, in South America, at 10.34 GMT.
But the launch was called off less than 90 minutes beforehand, with an unnamed official from the Russian space agency telling the Interfax news agency that "a problem occurred during the fueling of the third stage of the rocket."
The European Space Agency (ESA) website, which had been streaming the failed launch in real time, said: "Soyuz and its two Galileo IOV satellites, along with the launch facility, have been placed in a safe mode".
The European Commission has set a new launch date for Friday at 10.30 GMT.
Galileo has been described as “a multibillion dollar gamble", and the first two navigation satellites to be sent into orbit are said to mark a significant step forward:
The BBC reports:
"The pair incorporate next-generation technologies that should deliver more precise timing and location data than the current American GPS network."
The European Space Agency describes the project as “Europe's Galileo satellite navigation constellation”, and a further 28 satellites will be required for its completion.
Friday's launch will be particularly historic, reports Agence France Presse, because it will mark the first time the Soviet-era rocket — the world's most successful, with 1776 launches under its belt — has been deployed outside Russia's bases.
Soyuz has always been launched from Plesetsk, in northern Russia, or Baikonur, in Kazakhstan.
Russia agreed to launch Galileo from the European Space Agency's base in Kourou, French Guiana, under a deal signed in 2003.
"By launching its treasured child abroad, Russia gained precious income for its beleaguered space industry.
"In exchange, Arianespace, which markets the ESA's rockets for satellite launches, got a medium-range vehicle to go alongside the heavy Ariane 5, and a future lightweight rocket, the Vega."
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So what's so great about Galileo? Apparently it carries more precise atomic clocks, compared to GPS. Plus data transmitted by Galileo is expected to be more accurate than its American counterpart.
A fixed Galileo signal would have an error margin of about a meter, compared to 10 meters for GPS.
The BBC reports that the Soyuz will put the two Galileo spacecraft at an altitude of 23,222 kilometers. From here, they will orbit the Earth every 14 hours.
Along with two additional platforms set for launch next year, these satellites will “test and validate the Galileo system end-to-end”.
Of the 28 satellites needed to complete the Galileo constellation, and the European Commission has so far only purchased 18. They are set for launch between now and early 2015.
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