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The Blok DM-03 ((ロシア語:Блок ДМ-03) meaning ''Block DM-03''), GRAU index ''11S861-03'', is a Russian upper stage used as an optional fourth stage on the Proton-M carrier rocket. Two have been launched, the first in December 2010,〔 however as of July 2013 the stage is yet to be demonstrated in flight as both launches failed before fourth stage ignition, the first as a result of a problem with the Blok DM's fuel load.〔 Initial versions of the Blok DM-03 are powered by a single RD-58M engine, fueled by RG-1 and oxidised by liquid oxygen. The last evolution is powered by the improved RD-58MF a less powerful but more efficient evolution of the venerable engine. It can carry 25% more propellant than the Blok DM-2, which it replaced as a Proton upper stage for some government launches.〔 However most government launches and all commercial missions use the Briz-M instead. The payloads for the first two Blok DM-03 launches were groups of three Uragan-M satellites for the GLONASS programme, with further missions slated to carry three more Uragan-M satellites, and two Ekspress satellites on separate launches. The Blok DM can inject payloads into orbit more accurately than the Briz-M,〔 making it better suited for launching satellites such as the Uragan-M which lack apogee motors. When production ended in 2012, five Blok DM-03 stages had been produced by RKK Energia, for use on Proton and potentially Zenit rockets.〔 A new version of the upper stage is expected to be introduced once the five launches are complete;〔 all five DM-03s have been slated for Proton launches between 2010 and 2015. During a November 2014 interview, Vladimir Kolmykov, the Deputy General Director of the Chemical Division of Krasnoyarsk Machine-Building Plant, stated that the production of Block-DM was suspended during that year, but work on the stage and development of the RD-58MF will resume during 2015.〔 ==Versions== The development for the 11S861-03 stage is covered under the Dvina-DM (Russian: ) program. The specifications of this program (''Technical requirements on development work «Modernization of the upper stage «DM» for the carrier rocket heavy class»'') defines three different evolutions of the 11S861-03 stage:〔 *11C861-03 Phase I Version 1: This version main task is the enlargement of the propellant tank with minimum modificaitons. The target performance metric is to GEO and to a GTO. Its improvements is: * *Increase of tank size to . *11C861-03 Phase I Version 2: This version will introduce general performance improvements. The target performance metric is to GEO and to a GTO. Its improvements are: * *Replacement of the avionics and instrumentation enclosures. * *The use of advanced control unit. * *Replacement of the Navigation and Telemetry systems Chezara Kvant-VD (Russian: ).〔 * *Adapted for using the Proton-M's fairing type 14S75 of . * *Structural improvements to reduce the dry weight. *11C861-03 Phase II: This change will finally apply the new propulsion unit: The target performance metric is to GEO and to a GTO. Its improvements are: * *Switch engines to the 11D58MF. * *Use the main engine for RCS and ullage. * *Structural weight reduction. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Blok DM-03」の詳細全文を読む スポンサード リンク
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