PARIS — Europe’s Ariane 5 ECA heavy-lift rocket on Nov. 26 successfully placed U.S.- and European-built telecommunications satellites into orbit, one of which represents the first public-private partnership in satellite building undertaken by the 18-nation European Space Agency (ESA).

The launch was the fifth of six Ariane 5 flights planned for 2010 by Evry, France-based Arianespace, the vehicle’s operator.

Operating from Europe’s Guiana Space Center spaceport in French Guiana, the Ariane 5 placed into transfer orbit the Intelsat 17 satellite for Luxembourg-and Washington-based Intelsat, and the Hylas-1 broadband satellite owned by start-up operator Avanti Communications of London.

Intelsat said its satellite was healthy in its transfer orbit and sending signals. Avanti officials could not be reached immediately for comment.

Weighing 5,540 kilograms at launch, Intelsat 17 was built by Space Systems/Loral of Palo Alto, Calif. It carries 25 Ku- and 24 C-band transponders and will replace the aging Intelsat 702 at 66 degrees east. Intelsat uses the slot to provide a broad swath of Asia and the Pacific with television programming.

Hylas-1 was built by a joint venture of Astrium Satellites of Europe, which provided the payload electronics, and the Indian Space Research Organisation’s Antrix commercial arm of Bangalore, India. It is the second commercial satellite produced by the joint venture, after Eutelsat’s W2M. W2M suffered a power-system failure soon after its launch in early 2009, but it still provides partial service.

Astrium built Hylas-1’s flexible payload in part with financing from ESA’s telecommunications research program, which in this case was backed mainly by the U.K. Space Agency. The satellite weighed 2,570 kilograms at launch and will operate at 33.5 degrees east longitude. It carries eight Ka-band channels and two in Ku-band.

The payload was more difficult for Astrium to complete than expected, resulting in several months of Hylas-1 delays. The two Ka-band antennas, each responsible for different regions, generate eight spot beams. Bandwidth allocated to each beam can be adjusted from the ground based on demand for Ka-band consumer broadband links in Europe.

Similar features are being integrated into several new broadband satellites to avoid the problem encountered by consumer broadband provider WildBlue Communications of the United States. The WildBlue-1 satellite’s beams are fixed and cannot allocate resources to meet evolving demand, resulting in WildBlue-1 having some beams that are sold out and must turn away customers, while other beams are nearly empty and serve low-demand regions.

ESA is co-financing development of two other satellites — the large AlphaSat platform to be used by Inmarsat of London for mobile communications, and the Small-Geo satellite platform that will be first used by Hispasat of Spain. Both satellites are completing development. Similar projects, including one to provide satellite data-relay services, are planned.

Hylas-1 is the first telecommunications satellite for ESA since 2001. The agency in recent years has decided to return to the sector.

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