A problem with the steering system on a Proton rocket has forced an indefinitely delay in the launch of the SES 5 communications satellite, which had been set to take off Monday from Kazakhstan, according to the launcher's Russian contractor.

The Proton rocket was rolled to the launch pad Sunday. Credit: Khrunichev
 
The Proton rocket rocked was already installed on the launch pad at the Baikonur Cosmodrome in Kazakhstan for liftoff Monday. But after initially announcing a 24-hour delay, the Proton rocket's builder - Khrunichev - issued a statement Tuesday saying there would be a further launch slip.

A new launch date has not been announced.

A statement posted on Khrunichev's website said testing revealed a "disruption" in the steering system on the first stage of the Proton rocket. The Proton's first stage is powered by six RD-276 engines generating up to 2.5 million pounds of thrust.

International Launch Services, a U.S.-based firm which manages commercial sales of Proton rocket launches, said the 191-foot-tall booster would be returned to a processing facility for corrective action.

"On June 18, Khrunichev engineers at the launch site received an out of tolerance telemetry reading on a first stage subsystem during pre-flight testing," ILS said in a statement. "However, based on additional pre-flight testing performed on June 19, it was determined that further investigation is necessary, requiring the launch vehicle be returned to the processing hall for additional testing. The vehicle and satellite remain in a safe configuration at the launch site."

The launch of the SES 5 payload will be the fifth commercial Proton flight of the year under the auspices of International Launch Services. Including launches for the Russian government, it will be the sixth Proton mission of the year.

The SES 5 communications satellite's Ku-band payload will support direct-to-home television services over Africa and the Nordic and Baltic countries of Europe. C-band transponders will enable maritime communications, mobile services and video distribution.

The spacecraft, built by Space Systems/Loral, will be stationed in geosynchronous orbit at 5 degrees east longitude during a 15-year mission for SES, a world-leading communications satellite operator based in Luxembourg.

SES 5 also carries a European Geostationary Navigation Overlay Service, or EGNOS, L-band hosted payload to supplement positioning data over Europe from the U.S. Air Force's GPS satellite network, Russia's Glonass system, and Europe's Galileo navigation satellite constellation.

The EGNOS program is managed by the the European Commission, the European Space Agency and Eurocontrol, the European organization for the safety of air navigation.