A Boeing Delta 3 rocket's failure last May resulted from a combustion chamber breach, due at least in part to poor manufacturing, according to an interim report by a Boeing investigation panel. The rocket's premature shutdown resulted in a communications satellite being placed into a useless orbit.

The board's findings are similar to their preliminary analysis announced in June. However, the new report goes into greater detail about the possible causes of the combustion chamber breach. The panel is continuing its analysis in order to prepare the Delta 3 program for a return to flight.

The Boeing panel asserted that the combustion chamber had structural flaws due to inadequate brazing, or soldering, of a reinforcement strip, and that these defects were not detected due to "poor manufacturing process controls." The panel said the structural flaws caused the failure, possibly combined with unexpectedly high pressures or other "transient conditions" during launch.