MUNICH — The European Space Agency’s decision to order a second navigation satellite from small-satellite specialist Surrey Satellite Technology Ltd. (SSTL) of Britain was done only as a safety measure to assure an unbroken use of radio frequencies in orbit, according to Giuseppe Viriglio, ESA‘s director of telecommunications and navigation.

Viriglio said the Giove-A2 satellite to be built by SSTL will not be launched unless a navigation spacecraft under construction by a competing industry consortium fails at launch. That satellite, called Giove-B, is about two years behind schedule and is now expected to be launched in December.

ESA’s contract with SSTL, announced March 5, calls for the satellite to be ready for launch by mid 2008 and highlights the difficulties encountered by the competing contractor, European Satellite Navigation Industries — formerly called Galileo Industries — in building a more-sophisticated Galileo test satellite.

The Giove-A2 spacecraft will be nearly identical to the SSTL-built Giove-A spacecraft launched in December 2005. ESA said March 5 that the new contract, which needs to be approved by ESA’s Industrial Policy Committee, will be valued at between 25 million and 30 million euros ($33 million-$39.6 million).

In a March 6 interview here at the Munich Satellite Navigation Summit, Viriglio agreed that the new SSTL contract had not been planned when ESA was assembling the budget for Galileo.

Viriglio said the Giove-B satellite, after several technical difficulties requiring payload equipment replacement, is on track for a December launch aboard a Russian Soyuz rocket.

SSTL’s Giove-A2, he said, “will not be launched unless we have a launch failure on Giove-B. We view this as a prudent measure to assure that we continue to use the Galileo frequencies in orbit even if Giove-B fails.”

Phil Davies, SSTL’s senior account manager, said March 5 that Giove-A was designed to operate for 27 months in medium-Earth orbit. Davies said the satellite is working well, and that there is no reason to think it cannot operate for at least another two years.

ESA officials here said Giove-A is operating at about 86 percent availability, which they said is superior to expectations given the way they are using the satellite, including multiple switch-ons and switch-offs.

Giove-A has already secured Europe’s right to use the radio frequencies assigned Galileo. But should Giove-A fail, a replacement satellite would need to be in orbit within two years or the reserved frequencies could be confiscated under the rules established by the International Telecommunication Union of Geneva, a United Nations affiliate.

The SSTL contract is the latest example of the difficulties of European Satellite Navigation Industries. This consortium, assembled especially for the Galileo work, began building Giove-B at the same time as SSTL started work on Giove-A.

Fifteen months after the SSTL-built Giove-A was launched, Giove-B is still on the ground following component glitches and what ESA and industry officials agree were difficulties inherent in getting large contractors — Alcatel Alenia Space, Finmeccanica, Astrium GmbH, Astrium Ltd., Thales and a group of Spanish companies — to work together with clear lines of authority.

ESA Director-General Jean-Jacques Dordain has ordered Viriglio to come up with concrete recommendations to improve the consortium’s operations by the end of March. The consortium was formed mainly because of political considerations — assuring a balance of French, German, Italian, British and Spanish companies — and not because ESA could not find industrial expertise elsewhere. This political dimension limits ESA’s ability to make radical changes to the consortium, Viriglio agreed.

Didier Faivre, head of ESA’s navigation programs, said here March 7 that the consortium has failed to pay about one-half of its subcontractors despite the fact that the 1-billion-euro contract with ESA was signed in December 2005.

“This is becoming a real threat to the program,” Faivre said. “There is the possibility that some contractors will quit the work because they have not been paid.”