spacetoday.net: Proton cleared to resume launches

Posted: Sat, Dec 11, 2010, 10:30 AM ET (1530 GMT)
Proton launch of Glonass satellites on 2010 Dec 5 (Roskosmos)

A preliminary investigation into this week's failed launch of three GLONASS satellites has ruled out the Proton launch vehicle, allowing the vehicle to resume launches later this month. International Launch Services (ILS), which markets the Proton commercially, said that the preliminary investigation found nothing wrong with the lower three Proton M stages during the December 5 launch. Investigators now believe that the problem may be with the Energia-built Block DM-03 upper stage, making its first flight; reports suggest the upper stage may have been loaded with too much propellant, making it too heavy to achieve orbit. The three GLONASS satellites it carried reentered the atmosphere about 1,500 kilometers northwest of Honolulu shortly after launch. The findings allow ILS and Khrunichev, which manufactures the Proton, to resume launches using Khrunichev's Breeze M upper stage. The next Proton launch, carrying the KA-SAT communications satellite for Eutelsat, was scheduled for December 20, but ILS said Friday it would delay the launch about a week to allow for a thorough review of the preliminary report.