Local ionospheric disturbance created by a burning rocket

Abstract

Ionospheric electron-density data were obtained from Faraday rotation measurements on a 73.6-Mc/s signal radiated from the Scout rocket NASA ST-7/P-21, launched from Wallops Island, Virginia, at 1238 EST on October 19, 1961. This Scout, a four-stage solid-fuel vehicle, created a severe ionospheric disturbance along its trajectory, since the third-and fourthstage propulsion periods occurred within the ionosphere. The receiving station was very close to the launch site, so that the 73.6-Mc/s propagation path was almost the same as the rocket flight path. At the same time, ionosonde records were obtained from a local sounding station. From a comparison between the results obtained from the ionosonde, the Faraday rotation method, and the high-altitude profile [Bauer and Jackson, 1962], an interpretation of the influence of the burning rocket on the ionosphere has been derived. It should be noted that the radio propagation technique is well suited for an investigation of this type, since the radio wave is initially propagated right through the disturbed region and it gradually moves out as the geometry of the rocket trajectory results in a sideways motion of the ray path. Thus, a rough estimate can be made of the nature and horizontal growth rate of the disturbance.The Faraday rotation measurement is essentially a measurement of the total number of electrons in a tube of unit cross-sectional area between the rocket and the ground, the axis of the tube being the line of propagation of the radio wave. The apparent local electron density at the rocket is derived from the rate at which this total electron content changes with rocket position. If the ionospheric profile is unchanged and if the rocket motion is radial, the rate of change measured represents the density at the rocket level. If the electron distribution is changing along the ray path, the measurements represent a combination of both the density at the rocket level and the change in total content along the ray path. Thus, in a disturbed ionosphere the apparent density measured can be either less or greater than the true density, depending on changes taking place at lower altitudes along the ray path. The apparent electron density derived from the Faraday rotation, and also the initial undisturbed electron-density profile obtained by reduction of the ionogram, are shown in Figure 1. Since the sideways displacement of the ray path with respect to the trajectory is an important consideration in the later discussion of the data, trajectory and typical ray paths are also included on the figure.The effects of the burning rocket on the apparent electron density can be seen to be as follows (where the regions A, B, and C referred to are indicated in the figure):A. Third-stage ignition occurred at an altitude of 120 km, and it resulted in very rapid and highly distorted Faraday cycles, which were interpreted as a large increase in local density. This is shown on the figure as a dashed curve, since an accurate measurement could not be derived from these distorted cycles...

Ground and Space-Based Measurement of Rocket Engine Burns in the Ionosphere

“…The explanation was given that the exhaust cloud "punched" a hole in the ionosphere. Subsequent observations by the NRL of an ionospheric hole left in the wake of a rocket exhaust burn were recorded using the Faraday rotation of linearly polarized transmissions to detect a reduction in total electron content (TEC) [17].…”

A large‐amplitude traveling ionospheric disturbance excited by the space shuttle during launch

“…The atmospheric transit of rockets has been shown by Booker [1961], Jackson et al [1962], Kellogg [1964], Stone et al [1964], Felker and Roberts [1966], Donn et al [1968], Arendt [1971], Mendillo et al [1975], Zasov et al [1977], Behnke and Duncan [1980], Bernhardt et al [1988a, b], and others to produce a variety of atmospheric effects. Among these effects is the generation of propagating disturbances.…”

Ionospheric effects during flights of the rocket «Soyuz» under magnetically quiet and magnetically disturbed conditions

“…Первые наблюдения эффектов вблизи траектории ракеты выполнены еще в 1960-е гг. В работах [15,17,18,25] показано, что при пролете ракеты образуются локальные ионосферные возмущения, в первую очередь уменьшение концентрации N электронов. В работах [19,21] было получено, что возмущения могут быть достаточно крупномасштабными.…”