Posted: Mon, Jan 20, 2003, 8:57 PM ET (0157 GMT)
A commission reviewing the failure of a Proton launch last November has concluded that some kind of particle contamination led to the failure of the vehicle's upper stage. International Launch Services (ILS), the company that markets the Proton commercially, said Monday that it had received a final report from the Russian state commission that investigated the November 26 failure, when the Proton's Block DM upper stage stranded the Astra 1K satellite in low Earth orbit. A preliminary report announced last month pinned the failure on excessive propellant in the engine at the beginning of the second of four planned burns, destroying the engine. The final report could not find a root cause for the failure, but believed that some kind of particulate contamination led to the failure. The commission concluded that either stray particles clogged manifolds through which propellant is drained after the first burn, or particles prevented a valve from sealing properly, allowing propellant to leak into the engine. ILS noted that this failure was similar to three other Block DM failures since 1996. ILS's own Failure Review Oversight Board plans to conduct an independent review of the failure, and officials said they do not plan to use the Block DM "until we are certain it is flight-worthy." A press release issued last week by RSC Energia, the Russian company that produces the Block DM, claimed that the failure was "an isolated case" and noted that the Block DM was used successfully last month on the Proton launch of three Glonass spacecraft.

Related Links:

•  ILS press release
•  Energia press release