A 2011 file photo of an Ariane 5 rocket rolling out to the launch pad. Credit: Arianespace

PARIS — Officials with the Arianespace launch consortium said July 6 that oil contamination concerns that postponed the launch of a European weather satellite and a Brazilian telecommunications satellite aboard an Ariane 5 rocket had been resolved and that the mission is now scheduled for July 15.

The launch of the MSG-4 and Star One C4 satellites had been scheduled for July 8 but was postponed after oil was spotted on the rocket’s fairing.

Evry, France-based Arianespace initially declined to specify the cause of the delay, saying only that “additional checks as part of the preparation of [the] mission” were needed before proceeding with the launch.

Industry officials said oil was found on the rocket’s fairing after it had been placed onto the vehicle. The oil had dripped from an overhead rail bridge that maneuvers both the fairing and the satellites onto the rocket in the final assembly building at Europe’s Guiana Space Center spaceport on the northeast coast of South America.

The previous use of the rail bridge was to carry the Star One C4 telecommunications satellite, owned by Star One of Brazil, into its place on the Ariane 5 rocket’s upper berth.

While oil on the outer surface of the rocket fairing would not by itself have caused a launch delay, the possibility that oil may have dripped onto Star One C4 was enough to force a re-inspection of the satellite.

Star One C4 was built by Space Systems/Loral of Palo Alto, California. Riding in the Ariane 5 lower berth for the mission will be the MSG-4 geostationary-orbiting meteorological satellite, owned by Europe’s Eumetsat organization of Darmstadt, Germany, and built by Thales Alenia Space of France and Italy.

Most Ariane 5 launches carry two commercial telecommunications satellites. Commercial fleet operators are especially sensitive to delays at the moment because the two other vehicles with substantial commercial backlog – Russia’s Proton and California-based SpaceX’s Falcon 9 – are both grounded following launch failures in May and June, respectively.

Industry officials said a mid-July meeting is planned in Moscow with Proton customers, insurers, the Russian government and Proton builder Khrunichev Space Center to review the cause of the May failure and proposed corrective action.

Early indications are that Proton could return to flight in September, and perhaps as early as late August.

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