Can molecular diffusion explain Space Shuttle plume spreading

摘要: [1] The satellite-borne Global Ultraviolet Imager (GUVI) has produced more than 20 images of NASA Space Shuttle main engine plumes in the lower thermosphere. These reveal atomic hydrogen and, by inference, water vapor transport over hemispherical-scale distances with speeds much faster expected from models thermospheric wind motions. Furthermore, expand rapidly. We find rates that exceed horizontal diffusion speed at nominal plume altitudes 104-112 km. Kelley et al. (2009) have proposed a 2-D turbulence mechanism to explain observed spreading (and rapid advection) plumes. But upon further investigation, we conclude H atom can indeed account for expansion recognizing vertical quickly conveys atoms higher where is rapid. also evidence production directly during Shuttle's burn.