The Boeing Delta IV Launch Vehicle – Pulse Settling Approach for Second Stage Hydrogen Propellant Management
- Paper number
IAC-06-D2.1.05
- Author
Mr. Michael Berglund, The Boeing Company, United States
- Coauthor
Mr. Mark Wilkins, Boeing Integrated Defense Systems, United States
- Year
2006
- Abstract
For each mission, the Delta IV launch vehicle is subjected to a rigorous flight readiness review process to ensure mission success. This process was derived from the flight-proven Delta II launch readiness review process. This disciplined process integrates functions from quality assurance, manufacturing, launch site processing, and engineering. The process consists of a series of reviews scheduled to validate and establish with a high degree of confidence that the launch vehicle and ground support equipment will perform reliably and meet mission objectives. Reviews are linked to key Delta IV launch milestones. The process progresses from production through post-launch data reviews and includes customers and independent assessment teams. During the flight readiness review process of a recent Delta IV mission, an independent review team Analex presented results from simulations of the behavior of the second stage cryogenic propellants. Their results were considerably different than what Boeing and the Aerospace Corporation were showing at the time. Boeing recommended that launch team stand down until the discrepancy between analysis results was resolved. A team, consisting of Boeing, the Air Force, the Aerospace Corporation, Flow Sciences, and Analex, together investigated this sloshing behavior. During the investigation, it was found that the sloshing behavior of the liquid hydrogen, during the second stage coast phase of flight, was not constrained in the aft end of the tank and presented an increased mission risk. The propellant in the forward tank dome at the same time as tank venting could lead to propellant ingestion into the tank vent relief system and result in a thrust imbalance. This paper will focus on the team’s investigative efforts and resolution of the issues associated with the sloshing, including the implementation of the pulse settling approach for propellant management.
- Abstract document
- Manuscript document
IAC-06-D2.1.05.pdf (🔒 authorized access only).
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