Tim Furniss/LONDON

The maiden flight of the uprated Russian Proton M booster will be made from the Baikonur Cosmodrome on 16 March.

The booster will carry the Ekran M24 television satellite, which will be the last in the series of this 2t spacecraft developed in the 1970s. It will be positioned at 99°E in geostationary transfer orbit (GTO) and will replace the Ekran M18.

The Proton M features several upgrades over its Proton K predecessor, including a digital flight control system and new engines.

The first stage will operate using a new version of the RD-253 hypergolic engines, with sea-level thrust increased by 19,800lb (88kN) to 360,000lb. Six RD-23s power the first stage.

With the standard second and third stages, the Proton M will be able to carry 22t payloads into low Earth orbit, including International Space Station modules, compared with the 21t capability of the Proton K.

A four-stage Proton M features the new multiple restart single hypergolic engine-powered Breeze M upper stage.

Proton K-Breeze M made its inaugural flight aboard a Proton K in July 1999, but the launch failed after a second-stage malfunction, according to the Molniya Space Consultancy.

The second Proton K-Breeze M launch last May was a success, and carried the final Gorizont series communications satellite.

The Proton K-Breeze M can carry a maximum of 3,200kg directly into geostationary orbit (GEO) compared with the Proton K's maximum demonstrated capability of 2,600kg, equipped with the cryogenic DM stage.

Molniya says comparative figures for GTO flights are 5,500kg and 4,940kg respectively.

The Proton M will be added to International Launch Services' inventory of Proton and Atlas launchers.

Builder Khrunichev plans further upgrades to the Proton, equipping it with the KB Salyut-KVRB cryogenic upper stage, which could place 4,500kg into GEO. "This will be the first Russian liquid-oxygen liquid-hydrogen cryogenic upper stage to be used," says Molniya.

Source: Flight International