Surface Pressure Produced by Space Transportation System Flight 41B.
Abstract
There is a need to measure and analyze the vibro-acoustic environment of Space Transportation System (STS) launches in order to forecast and verify facility design and lifetime predictions for STS operations at Vandenberg Air Force Base (VAFB), and to accumulate flight vehicle performance data. Earlier measurements at Kennedy Space Center (KSC) pointed to an azimuthal dependence in the overall sound power level (OASPL) for STS launches. The immediate aim of this effort is to clarify the azimuthal properties of surface pressure around the time of the OASPL maximum for KSC launches. The study helps define and locate a site insensitive STS source pressure equivalent essential to vibro-acoustic forecasts at VAFB. The dense watercloud produced by STS main engine firing at KSC attenuates surface pressure levels directly south of Pad 39A by as much as 14db. Spectra at stations under the cloud are lower in level and frequency content than those in the clear. The phase velocity for acoustics early in the launch is insensitive to watercloud effects for stations at 300 meters. Spatial coherence of the pressure field is degraded between stations 100 meters or more apart. Keywords include: Rocket plume acoustics; Acoustic coupling; STS seismic-acoustic fields; STS launch environment; and Kennedy Space Center.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1984
- Accession Number
- ADA150793
Entities
People
- E. B. Hartnett
- F. A. Crowley
- M. A. Fisher