The blast wave of the Shuttle plume at ionospheric heights

Abstract

The main engine burn (MEB) of the Space Shuttle deposits ∼2×1012 joules of explosive energy and ∼3×105 kg of exhaust in almost horizontal flight at 105–110 km altitude during the period 300–550 s into the ascent. This extremely robust perturbation provides a potential active‐excitation source for a variety of geophysical processes, including (1) the effects of aurora‐like localized heating on the generation of gravity waves in the thermosphere, (2) the ducting mechanisms for long‐period infrasound in the upper atmosphere, (3) dynamo effects associated with transient charge separation, (4) interactions with ambient midlatitude current systems at E‐layer heights, and (5) effects in the Earth‐ionosphere waveguide of transient electron‐density perturbations in the D‐region. The sine qua non of such an agenda is to gain a quantitative understanding of the near‐field behavior of the MEB exhaust‐plume's quasi‐cylindrical expansion, which generates a blast wave propagating away from the explosion. We report on observed electron‐density signatures of this blast wave as manifested on lines‐of‐sight (LOSs) from a very‐long‐baseline interferometer (VLBI) illuminated by 137‐MHz beacon signals from the MARECS‐B satellite. We also compare the observations to a preliminary three‐dimensional neutral‐air acoustic model coupled to the ionospheric electron density.