SAN DIEGO, March 18, 1996 – The first commercial Proton launch has been rescheduled for April 9 (early morning Baikonur time, early evening April 8 US Eastern time), International Launch Services (ILS) announced today. The launch had originally been scheduled for 28 March.

The launch delay provides time for technicians to replace a helium tank in the satellite’s propulsion system. Hughes Space and Communications Company engineers detected a leak in the tank during a pressure test of the tank prior to fueling the propulsion system at Baikonur Cosmodrome in Kazakhstan. The helium is used to pressurize the satellite’s fuel system. The satellite is built by Hughes for Societe Europienne des Satellites (SES), a Luxembourg-based company that is a prime provider of direct-to-home television and radio services to Europe.

ILS, a joint venture company formed by the Lockheed Martin Corporation and Russian companies Khrunichev State Research and Production Space Center and RSC Energia, is providing launch services to SES on the Russian-built Proton. This will be the first US-built satellite launched on a Russian rocket.

The satellite arrived in Baikonur on 14 February after being shipped by Hughes Space and Communications Company from Los Angeles International Airport. A replacement tank has been shipped to the launch site from Hughes in El Segundo, CA. The combined team of ILS, SES, Hughes and Russian technicians are continuing to process the satellite and launch vehicle to be ready for launch.

Regarding the 19 February failure of the Block DM fourth stage during the Proton launch of the Raduga satellite, ILS has met with the Khrunichev failure review teams and concurs with their analyses as well as the Russian government commission’s report. Failure analysis determined that at second ignition of the Block DM, the main engine experienced an emergency commanded shutdown. The probable cause of the failure was a pressure leak in the engine start system. The leak was most likely caused by an inadequate lockwire installation on a start system tube joint nut, which allowed the nut to back off under vibration. Corrective actions include increasing the lockwire diameter and adding a second, redundant lockwire to the affected joint. The corrective actions would have supported the original March 28 launch date for Proton/Astra 1F.

Proton has served as the primary heavy-lift launch vehicle for Russian unmanned space systems since the mid-1960s. Used in more than 200 launches, Proton has an outstanding reliability record – 96 percent for the last 50 launches. Proton is manufactured by Khrunichev at its Moscow-based factory. The Block DM is built by RSC Energia also in Moscow.

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