SPACE.com -- Proton rocket carrying Express 3A spacecraft to take off from Baikonur Cosmodrome

The artist rendering of the Express-A communications satellite. Credit: Intersputnik. Click to enlarge.

The positions of the active federal Russian communications satellite in the geostationary orbit. Click to enlarge.

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	Proton rocket carrying Express 3A spacecraft to take off from Baikonur Cosmodrome By Anatoly Zak Staff Writer posted: 11:03 am ET 22 June 2000

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Russia is preparing to take another step in rejuvenating its aging fleet of communications satellites.

A Proton rocket carrying the Express 3-A spacecraft is scheduled to take off from Baikonur Cosmodrome Thursday at 8:32 p.m. Eastern Daylight Time (Friday, 00:32 GMT). It will be the third Russian communications bird to go up in four months, and the second since the beginning of June.

The brand-new satellite follows its higher-numbered sibling, Express 6-A, launched in March and an older-generation Gorizont 45 spacecraft, which took off on June 6.

Russia has more than one reason for this surge in communication-satellite launches. It is struggling to meet the growing demand for communications services across its vast territory, which spans 11 time zones. Financial problems in the Russian economy have kept some new-generation spacecraft on the ground for years. Also, several vacant orbital slots Russia registered for its satellites almost a decade ago may expire unless a spacecraft is placed there soon.

Cargo boost

Soon after the Proton places Express 3-A into the initial parking orbit, an upper stage attached to the satellite will fire twice to boost its cargo into the higher orbit 22,300 (35,885 kilometers) over the equator. The satellite is due to be placed 11 degrees west longitude over the Atlantic, where it will replace an older Gorizont 26 spacecraft.

The Express As are built by the NPO PM development center located in the Siberian town of Zheleznogorsk. They are equipped with 17 communications transponders built by Alcatel Espace of France.

The Russian Satellite Communications Company, RSCC, owns the Express-series spacecraft, while Moscow-based Intersputnik is their primary user.

The launch of the Express 3-A comes in the midst of the biggest backlog of Proton launches in years. In addition to the June 6 launch, two Proton missions are competing for a launch window at the end of the month.

Proton scrutiny

All eyes are also on Proton -- on July 12 it is scheduled to launch the Zvezda service module, a crucial element of the International Space Station.

The failure of the Proton booster last October, with the first Express A-series spacecraft, pushed the already delayed service module another six months behind schedule. The Proton booster returned to flight on February 12 and since then it has successfully lofted four missions into orbit.