A review of the data indicates an anomalous event occurred at the time IUS Stage I and Stage II were to separate. Indications are that the IUS and the satellite were placed in the required low earth orbit. Approximately one hour and 15 minutes after lift off, the IUS SRM 1 fired to initiate the transfer orbit. Indications are that SRM 1 performed as expected. At six hours and 30 minutes after lift off, Stage I and Stage II of the IUS were scheduled to separate.
Data shows several anomalous events occurred during the separation sequence.
Specifically, although two separation break wires indicate separation had occurred, a separate connector continued to carry signals, indicating the separation was not complete. Under normal conditions, Stage II extends a compressed nozzle, called the extendable exit cone, after separation. When the extenders reach a certain pressure they swing away, or disengage, and that is taken as a signal that the cone is fully extended. In this case, one of the extenders disengaged within two seconds after receiving its command. Normally, the expected duration for a full extension is seven to eight seconds.