PARIS — Australia’s two national Ka-band broadband satellites will be launched on European Ariane 5 rockets in 2015 following a contract signed March 4 between NBN Co. of Australia and Europe’s Arianespace launch consortium, both companies announced.

Under the contract, which NBN said is valued at up to 300 million Australian dollars ($306 million), the 6,000-kilogram satellites will be launched in early 2015 and late 2015, the companies said.

The two spacecraft are under construction by Space Systems/Loral of Palo Alto, Calif., and are part of what is perhaps the world’s most extensive government broadband deployment program. NBN is using a mix of cable, terrestrial wireless and satellite technologies to assure that every Australian has broadband access by 2021.

The satellite service has already begun on an interim basis using Ku-band capacity.

Peter B. de Selding was the Paris Bureau Chief for SpaceNews.