PARIS — British satellite operator Avanti Communications has scored a second major coup with the European Space Agency (ESA) by contracting for the launch of a Ka-band broadband payload aboard an ESA data-relay satellite, according to Avanti and ESA officials.

A contract is scheduled for signing by early March confirming that London-based Avanti will spend some 73.8 million British pounds ($114 million) to place its Hylas 3 payload aboard ESA’s European Data Relay Satellite, EDRS, which is scheduled for launch in 2015.

EDRS’ main payload is a data-relay terminal to forward imagery from low-orbiting Earth observation satellites to their owners and customers without the need to first be sent to an Earth station. EDRS is being developed by the 19-nation ESA as a partnership with Astrium Services, which is managing the project in hopes of creating a business of providing the service to European governments.

On the strength of ESA’s promise to sign the agreement, Avanti raised a net 73.8 million pounds on the London stock market on Feb. 6.

Sean Watherston, Avanti’s director of investor relations, said in a Feb. 10 interview that Avanti will use the proceeds to pay ESA an “embarkation fee” to cover Avanti’s Ka-band Hylas 3 payload and a pro rata share of the satellite’s launch.

An ESA official said Feb. 9 the agency would decline comment on the Hylas 3 contract until it was signed. The official said the orbital slot for EDRS had yet to be determined.

Watherston also declined to say at which orbital position it would operate beyond repeating the company’s earlier statement that it would be an Avanti-provided position.

For Avanti, the Hylas 3 agreement follows its Hylas 1 satellite development contract with ESA. Hylas 1, launched in November 2010, was developed by ESA to test a new flexible payload. ESA was happy to have a private-sector operator take ownership of the satellite, and Avanti was able to take advantage of substantial research and development investment by ESA.

Similarly, Avanti will be piggybacking its commercial payload on an ESA-financed satellite platform. The agency is promoting these kinds of public-private partnerships and has undertaken similar investments with satellite operators Inmarsat of London and Hispasat of Spain.

Avanti’s Hylas 2 satellite, which was financed with backing from the U.S. Export-Import Bank and its French equivalent, Coface, is in final production at Orbital Sciences Corp. of Dulles, Va., and is scheduled for a July launch aboard a European Ariane 5 rocket.

Watherston also declined to specify the orbital slot intended for Hylas 2.

Speculation about Avanti’s orbital positions — the company says it has multiple filings with the British and other governments — mounted the week of Feb. 6 when the British delegation to the World Radiocommunication Conference (WRC) in Geneva abruptly changed its position on orbital slot registration rules.

More than 150 governments are represented at the WRC, a quadrennial conference that regulates satellite orbital positions and wireless broadcast frequencies.

According to three people attending the conference, including a representative in the British delegation, Britain’s longstanding support for clarifying rules on satellite-slot registration did an about-face.

As a leading member of the Conference of European Posts and Telecommunications agencies, Britain had helped coordinate a common European position that a satellite would need to stay at its intended slot for up to three months before being declared “brought into use,” in the language of the International Telecommunication Union, under whose auspices the WRC conferences are held.

“The British delegation has turned 180 degrees on this point, apparently on behalf of Avanti,” said one official attending WRC. “Many delegations [at WRC] are confused about why.”

Another WRC attendee said: “The U.K. delegation is now pushing for a ‘bringing into use’ limit of just 15 days. This was a surprise, to say the least.”

Britain’s telecommunications regulator, the Office of Communications, agreed on Feb. 8 that the delegation’s position had changed, but declined to disclose its reasoning until the WRC conference ends on Feb. 17.

Avanti’s Hylas 1 operates at 33.5 degrees west in geostationary orbit. But two officials familiar with the satellite’s launch said that before being stationed there, Hylas 1 spent one month for in-orbit testing at 61.5 degrees east, and then 16 days at 31 degrees east.

These two orbital slots — 61.5 degrees east and 31 degrees east — figure in British ITU filings for satellites.

Each orbital slot and associated frequencies must be brought into use within seven years from the date it was registered. According to the ITU data, one of the four British registrations for 31 degrees east expires this May.

One of the four registrations for 61.5 degrees east also expires in May.

The other six registrations, three at each position, have later deadlines because they were registered later, meaning the British filing may not have priority at the slot compared to others who filed earlier. ITU registrations are run on a first-come, first-served basis.

Avanti’s Watherston said the company’s planned orbital slots are not those with a May 2012 deadline.

“This company has been subjected to more due diligence than any other satellite operator,” Watherston said. “We have raised some $330 million from the Ex-Im Bank and Coface and Barclays, and their lawyers have pored over our documents. They would not have overlooked this. It would be unconscionable that you would undertake a project like this with just a month or two, or even six months, of margin. We have no concerns about orbital-slot deadlines.”

Peter B. de Selding was the Paris bureau chief for SpaceNews.