Boeing says that a guidance system failure caused the $225 million loss of the first Delta III booster and its PanAmSat Galaxy X communications satellite on 26 August. The system apparently "overcompensated" after the booster experienced an oscillating roll beginning at T+55s and then was "overwhelmed" as the vehicle eventually went out of control, pitching 35° to the right and breaking apart at about T+72s. The cause of the initial abnormal roll has not yet been identified. The next Delta III launch is not expected to take place until February 1999. PanAmSat is reported to be looking for an alternative launcher for its Galaxy XI, which had been scheduled to fly on the first Boeing-led Sea Launch vehicle. The Delta III booster now has 17 satellites on its manifest.
Source: Flight International