TIM FURNISS / LONDON
Conversion of launch pad under way to prepare for operation of Zenit 3SL vehicle
Russia has started to convert a launch pad at the Baikonur Cosmodrome in Kazakhstan to operate the international Sea Launch Zenit 3SL vehicle for commercial missions.
The 3SLuses a standard Zenit 2 booster - which have been operating from Baikonur since 1985 - with a DM upper stage from the Proton rocket of the type used on the failed launch of the Astra 1K satellite in November 2002.
Previous Sea Launch missions have been made from the Odyssey offshore platform on the equator in the mid-Pacific Ocean, enabling fuel-efficient launches of 6,000kg (13,200lb) payloads to geostationary transfer orbit. Launches from the higher latitude of Baikonur would reduce this payload capability significantly, but would be cheaper.
The so-called "Land Launch" project began in 2001 to address the high costs of operating the Odyssey system, despite the advantages of its equatorial launch location. The commercial quandary has been exacerbated by the downturn in the communications satellite market and consequent fall in forecast commercial launches and increased competition among launch service providers.
The Baikonur option for Sea Launch was part of the agreement with the venture's Ukrainian and Russian partners when the Boeing-led company was established in 1994.
Meanwhile, the failure of a Proton K on 26 November 2002 during an International Launch Service mission - which resulted in the loss of the Astra 1K satellite - was caused by excess propellant in the Block DM upper stage engine's gas generator caused by a blocked fuel line, says an inquiry board.
This led to overheating and an explosion during ignition of the second burn of the stage, causing the satellite to separate in a low transfer orbit from which it could not be recovered.
The excess fuel resulted from "occasional plugging of the fuel drainage pipelines" after the first engine burn, says the report, which implies poor workmanship was responsible. The DM stage has been used 246 times with 236 successes and 10 failures.
Sea Launch has flown seven successful launches with one failed flight from Odyssey since 1999 and was originally scheduled to make four commercial launches this year.
Source: Flight International
