Proton Returns To Duty with Launch of Three Navigation Satellites

PARIS —


A Russian Proton-K rocket




successfully placed three Glonass-M navigation satellites into orbit in an Oct. 26 launch that returned Russia’s Proton vehicle to service for the first time since




a Sept. 6 launch failure, according to the Russian space agency, Roskosmos.

The launch from the Russian-run BaikonurCosmodrome in Kazakhstan paved the way for the return to service of the commercial version of Proton, called Proton-M, which uses a different upper stage.

Roskosmos
and International Launch Services of McLean, Va., the company that markets commercial launches of Proton-M,




have said they plan to place the Sirius-4 telecommunications satellite, owned by SES Sirius, into geostationary-transfer orbit




Nov. 18.

It was a commercial Proton-M vehicle that failed shortly after launch




Sept. 6, destroying Japan’s JCSAT-11 telecommunications satellite, which was insured for $185 million.

A Russian government failure review concluded that a defective cable prevented Proton’s first and second stages from separating, causing the vehicle to crash onto the Kazakh steppe. The lower stages of the Proton are common to both the Proton-K and Proton-M rockets, meaning the commercial version has, in effect, reflown as well.

Satellite underwriters often assign different insurance premiums depending on a rocket’s recent flight history, and they prefer to cover vehicles that




already have demonstrated a successful flight after a failure.

Once they enter service, the three 1,415-kilogram Glonass-M satellites launched Oct. 26 will bring to 10 the number of modernized Glonass vehicles in the current Glonass satellite constellation.

Glonass
-M spacecraft, built by the same Russian company, NPO-PM, that manufactured the previous-generation satellites, are designed to operate for seven years, compared to four years for the previous generation. Glonass-M spacecraft also include a second civil signal, improved on




board clocks and an upgraded solar panel pointing system.

A further evolution of the Glonass satellites, called Glonass-K, is expected to be in service starting in 2009. These satellites will have a 10-year service life, and a third civil signal.

The Russian government has said returning the Glonass system to full operational health, with 24 in-service satellites, is a priority and for the past two years it has made good on its promise to invest in system upgrades.

But there is still a long way to go before Glonass, like the U.S. GPS system, has sufficient operational and in-orbit reserve capacity to be considered as fully functional for global users.

Before the Oct. 26 launch, 11 Glonass satellites were considered as operational, but only nine of them were classed as healthy enough for full service, according to a Sept. 25 presentation by Sergey G. Revnivykh, a Glonass specialist with Roskosmos, during a meeting of the U.S. Civil Global Positioning System Service Interface Committee in Ft. Worth, Texas.

Revnivykh
said the Glonass upgrade program, which has been endorsed on several occasions by Russian President Vladimir Putin, is likely to reach 18 operational satellites by early 2009 before dipping to 16 active spacecraft as older models are taken out of service.

New launches, and the addition of the higher-performance Glonass-K and Glonass-KM satellites, are expected to bring the constellation to 24 operational spacecraft by early 2011.