A cluster of navigation satellites will be the Proton rocket's first payload when Russia's most powerful booster returns to service after two failures last year.

Sergei Gorbunov, the head of the press service at Russia's Aviation and Space Agency (Rosaviacosmos), told space.com that three GLONASS spacecraft are now assembled. But the Russian government still must pay the manufacturer before craft are delivered to the Baikonur launch site in Kazakhstan for integration with the launch vehicle.

GLONASS is designed by NPO PM, based in the Eastern-Siberian town of Zheleznogorsk and built by the Polet Production Association in Omsk. The spacecraft are used by both Russian military and civilian organizations for the highly accurate navigation of ships, planes and other vehicles. GLONASS is the Russian equivalent of the Global Positioning System (GPS) used in the U.S.

According to Vladimir Bartemiev, the NPO PM representative, the GLONASS spacecraft are currently going through final testing at the Polet production facility in Omsk, and the satellites could be delivered to the launch site in Baikonur within a month. Four to five weeks are required for processing and integration of the spacecraft with the launch vehicle, which probably pushes the first launch to the end of February or the beginning of March.

Rosaviacosmos faced a difficult choice when selecting the payload for the Protons post-crash inaugural launch. The owners of the long-delayed Garuda communications satellite, influenced by their insurers, refused to allow their spacecraft to be flown first.

The Garuda spacecraft belongs to Asia Cellular Satellite, or ACeS International, which plans to deliver mobile voice and data communications services in the Asian-Pacific region. The spacecraft is expected to be the world's first geostationary satellite system linking directly to small dual-mode handsets.

The spacecraft's $600 million price tag was considered too high to put it on the first launch, Gorbunov said.

Rosaviacosmos representatives confirmed that there were proposals to launch a weighted mock-up instead of a real payload on Proton -- the common practice for the new types of launch vehicles. However, the expendable Proton rocket alone costs 400 million rubles (about $20 million), which was also too expensive to launch without a payload, Gorbunov said.

Russian space officials said that Garuda would be the second in the long list of the payloads to be launched by Proton. If the February launch of the GLONASS constellation goes smoothly, Garuda could go up in the near future. Facilities in Baikonur can handle parallel processing of multiple vehicles and payloads.

Rhea McGrow, AceS representative in Jakarta, Indonesia, told space.com that there is no official word on Garuda's schedule. She said the spacecraft could be launched in late February.

International Launch Services (ILS), a joint venture between Khrunichev and Lockheed Martin, confirmed that Garuda is first on the list of the ILS launches.

ILS Public Affairs Director Julie Andrews said the actual date of the Garuda launch would depend on the findings of the companys Failure Review Oversight Board (FROB), whose conclusions are expected to come this week.

FROB completed its work in Moscow last week, reviewing the corrective actions planned by the Russian industry in producing Proton engines.

A Russian investigative commission blamed manufacturing flaws in the second-stage engines as the cause of the two most recent Proton launch failures.

Andrews would not say whether FROB would agree with either the Russian commission's findings, or with the corrective actions planned for the engine production.

• CD Radio satellites for Sirius Satellite Radio Inc. A total of three Proton launches are booked by the ILS for this type of satellite
• ICO satellites for the ICO Global Communications, a cellular phone company. A total four Proton launches are committed for ICO launches, but their status has been after ICO declared bankruptcy last year
• three spacecraft for GE American Communications
• three launches of Teledesic satellites
• one launch of an Intelsat 901 satellite and one of a PanAmSat 10 satellite

• An Altair data relay spacecraft has reached the final stage of production. But Rosaviacosmos and the Russian Ministry of Defense, which originally ordered the craft, have yet to pay to the manufacturer. Russian space officials continuously indicated that they want the satellite to be in orbit before the Zvezda module, a crucial element of the International Space Station (ISS), is launched. Altair would provide a data relay support to the Russian mission control during crucial docking maneuvers between the ISS and Zvezda. According to Rosaviacosmos, the space agency and the Russian Ministry of Defense came to an informal agreement to share the price of the spacecraft. But they could not confirm whether or not plans to launch Altair before Zvezda have been finalized. Recently, Rosaviacosmos said that two or three Proton launches would take place before Proton carries Zvezda.

• An Express A communications satellite, the sibling of the spacecraft destroyed in the October Proton failure.

• An Ekran spacecraft for radio and telecommunications across Russia is in production at NPO PM. This craft's launch status is undetermined at this time.