Infrasonic Observations of the Final Flight of Space Shuttle Atlantis
Abstract
Infrasound arrivals from the July 2011 Space Shuttle Atlantis launch and re-entry were observed ~2,500 km away at Sandia's (SNL) Facility for Acceptance, Calibration and Testing (FACT) seven-element infrasound array. Space Shuttle Atlantis (STS-135) launched from the Kennedy Space Center (Florida) on July 8, 2011 for its final 14 day mission, culminating in a successful re-entry and landing on July 21, 2011. Infrasound from both the launch and the re-entry were clearly observed at the SNL FACT array due to the seasonal zonal wind reversals in the stratosphere and the quiet of early morning for the re-entry. In the northern hemisphere summer infrasound sources originating east of the array are observed more clearly than sources west of the array. While both the launch and re-entry were observed, the duration of detection, trace velocity, and correlation across the array varied. The launch was detected at the array for ~2 minutes while the re-entry was observed for a considerably greater amount of time, ~25 minutes. The launch of the shuttle produced less detectable infrasound because the trajectory carried the shuttle east, away from the array and disturbed the atmosphere to a lesser extent than at re-entry. During re-entry the shuttle passed much closer to the array, displaced more atmosphere, and generated infrasound for a longer period of time. The correlation across the array increased dramatically over background, peaking above 0.4 for the launch and over 0.9 for re-entry. In both cases the trace velocity stabilized between 0.35 and 0.38 km/s above background. Using FK processing we determined a back azimuth for the launch that correlated well to the location of the launch site at ~100°. Due to the higher, supersonic velocities of the shuttle and the atmospheric disturbance of re-entry, we were able to calculate several back azimuths over the duration of the observed signal. The back azimuths correlated very well with trajectory data provided by NASA and corresponded to the first detection of the shuttle as it flew past the east coast of the Yucatán Peninsula and the west coast of Cuba, ~120°. The final azimuth that we were able to calculate showed the shuttle over the west coast of Florida as it prepares to land, ~104°.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.A31A0032J
- Keywords:
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- 0394 ATMOSPHERIC COMPOSITION AND STRUCTURE / Instruments and techniques;
- 3399 ATMOSPHERIC PROCESSES / General or miscellaneous