The second trailblazer in Europe's sat-nav system, Galileo, is set for launch in the autumn, following the success of the first spacecraft.
Mission managers are confident they now have enough data from the first satellite, Giove-A, to secure the network's allocated frequencies.
This means there is now no urgency to fly Giove-B, which was originally set for lift-off this spring.
By 2010, the 3.4bn-euro (£2.3bn; $4bn) project will comprise 30 satellites.
It will deliver precise navigation and timing data across the globe.
Analysts expect the new constellation to drive a multi-billion-euro industry, creating perhaps 140,000 jobs.
Sat-nav has countless applications in the daily lives of consumers, from car guidance systems to feature-packed mobile phones.
While public signals from the Global Positioning System (GPS) are already widely used by the likes of sailors, mountaineers and motorists, the US military reserves the right to limit their use or switch them off for security reasons.
In building Galileo, European states are seeking a system over which they have independent control.
'Experimental scope'
Giove-A was built in the UK by Surrey Satellite Technology Ltd (SSTL). It was launched on 28 December from the Baikonur Cosmodrome in Kazakhstan.
The spacecraft's primary task was to secure the frequencies allocated to Galileo by the International Telecommunications Union (ITU).
Giuliano Gatti, of the European Space Agency, said the experiments needed to satisfy the ITU had been completed, and the data would now be submitted for scrutiny.
This means there is a period of grace for Giove-B.
"The (Giove-A) satellite is performing very well and therefore there is no urgency to launch immediately Giove-B," Mr Gatti told the BBC News website.
He said the second test satellite would now be launched some time between September and November.
"At that time, we will have the result of experiments with Giove-A," he added.
"By launching two satellites, we can extend the experimental scope."
Hi-tech clock
The contract to build Giove-B was awarded to Galileo Industries, a consortium that includes UK-based EADS-Astrium. It will demonstrate key technologies not on the first satellite.
THE SAT-NAV FUTURE
These include a hydrogen maser clock, one of the key components of the Galileo set-up that should allow users to pinpoint their position on the planet down to a few centimetres.
"It is a new space-based technology," commented John Paffett of SSTL.
"It will give the Galileo system high-precision accuracy for satellite-navigation position determination."
Winning the contract to build Giove-A was regarded as a major coup for the small Guildford-based company SSTL, a spin-off from the University of Surrey.
The success of the mission was marked on Friday at a ceremony organised by the European Space Agency.
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