PARIS — Satellite fleet operator SES’s struggles with its Ariane 5 launch co-passengers continued Nov. 13 with the announcement that the Amazonas 4A satellite, scheduled to share an Ariane 5 launch with SES’s Astra 5B, would not be ready for an early-December liftoff.

Amazonas 4A is owned by Hispasat of Spain. Hispasat issued a statement saying “a number of adjustments … need to be made to boost the satellite’s reliability … stemming from an anomaly detected during one of the last tests of the Amazonas 4A before being transported to the launch pad. 

“Although tests show that any risk is remote, Hispasat prefers to resolve any problems affecting a satellite’s performance, however small, before launch given that it considers the robustness and reliability of its satellites to be of paramount importance.” 

Amazonas 4A was built by Orbital Sciences Corp. of Dulles, Va., in what Hispasat described in late October as “record time.”

The Evry, France-based Arianespace launch consortium and Luxembourg-based SES announced the launch delay separately Nov. 13.

SES said it is now counting on a January launch.

The Ariane 5 flight had been moved up to early December from mid-December following the approval of Hispasat and SES in order to leave enough time for the launch service provider to redeploy its ground tracking antennas to support a Dec. 20 flight of Europe’s Gaia star-mapping satellite.

Gaia will be launched on a Europeanized Soyuz rocket, which operates from a separate launch installation near the Ariane 5 facilities at Europe’s Guiana Space Center spaceport on the northeast coast of South America. The Gaia launch campaign, which was delayed by a last-minute satellite issue of its own, will not be affected by the Ariane 5 delay, an Arianespace official said.

SES said its Astra 5B telecommunications satellite, built by Astrium Satellites of Europe, will be stored at the Guiana site in anticipation that Amazonas 4A will be ready for a January liftoff.

For SES, it is the second time this year that Astra 5B’s launch has been delayed because of a last-minute problem with a co-passenger. The scheduled launch this summer with the Optus 10 satellite owned by Australia’s Optus was scrubbed when Optus 10 was pulled from the manifest pending a possible sale of Optus.

Arianespace, which occasionally struggles to find lighter-weight passengers to accompany heavier satellites on Ariane 5, scrambled to find a replacement and settled on Amazonas 4A.

SES, along with the French space agency, CNES, has said Arianespace’s second-passenger problem with Ariane 5 is one argument on behalf of an immediate program to build an Ariane 6 successor that would be modular in nature and carry one satellite at a time. European governments are expected to decide in December 2014 whether to proceed with full development of Ariane 6. A positive decision would mean the next-generation rocket would be available around the end of the decade.

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