scope:

Description of Driving Event:

While pressurizing the oxidizer propellant tank, a change in ullage pressure of 8 psi occurred and caused the computer program to indicate that the interface and supply valves were closed. At this point, the engineer felt it was safe to close the dome load valve, in reality opening it. He then opened the interface valve, the pressure online with the module was 190 psig, the supply valve was then opened and the pressure spiked to approximately 400 psig, which ruptured the burst disk. The computer program indicated the incorrect status of the system because the control logic limits were not adjusted/reset prior to starting the operation.