Stardust—An artificial, low-velocity

Abstract

On January 15, 2006, Stardust, a man-made space capsule, plummeted to Earth for a soft landing after spending seven years in space. Since the expected initial speed of the body was about 12.9 km/s, a four-element ground-based infrasound array was deployed to Wendover, Nevada, USA, to measure the hypersonic booms from the re-entry. At a distance of ~33 km from the nominal trajectory, we easily recorded the weak acoustic arrivals and their continued rumbling after the main hypersonic boom arrival. In this paper, we report on subsequent analyses of these data, including an assessment of the expected entry characteristics (dynamics, energetics, ablation and panchromatic luminosity, etc.) on the basis of a bolide/meteor/fireball entry model that was specifically adapted for modeling a re-entering man-made object.Throughout the infrasonic data analyses, we compared our results for Stardust to those previously obtained for Genesis. From the associated entry parameters, we were also able to compute the kinetic energy density conservation properties for the propagating line source blast wave and compared the inviscid theoretical predictions against observed ground-based infrasound amplitude and wave period data as a function of range. Finally, we made a top-down bottom-up assessment of the line source wave normals propagating downward into the complex temperature/sound speed and horizontal wind speed environment during January 15, 2006. This assessment proved to be generally consistent with the signal processing analysis and with the observed time delay between the known Stardust entry and the time of observations of infrasound signals, and so forth.