The issue was identified as a faulty “oxygen relief valve” on the Centaur upper stage of the United Launch Alliance (ULA) Atlas V rocket. The valve was “buzzing,” opening and closing rapidly, during the launch countdown, causing the delay.
Analyzing Data and Determining Next Steps
The delay will enable teams to analyze data on the pressure regulation valve of the liquid oxygen tank in the Centaur upper stage and determine if a replacement is necessary.