Rocket Effluents Research Articles

An Analytic Model for Dispersion of Rocket Exhaust Clouds: Specifications and Analysis in Different Atmospheric Stability Conditions

This paper brings the first results concerning a new analytic model to evaluate atmospheric dispersion in rocket launch scenarios, namely the GILTTR (Generalized Integral Laplace Transform Technique for Rocket effluent dispersion) model. The model is constituted by three different modules, being them two pre-processors (micrometeorological parameters and deposition parameters) and the dispersion program. The dispersion calculations are made through the GILTT solution of the two-dimensional, time-dependant, advection-diffusion-deposition equation. The results show a set of simulations made using data from the Chuva Project from the Alcantara Rocket Launch Center (Brazil) for both stable and unstable planetary boundary layers (PBL), in order to evaluate model performance and illustration.

電離層におけるロケット排出物の拡散と電子減少

In coming new space age, we will have frequent trips between the ground and mission orbits by large rockets to realize the large projects such as space stations and solar power satellite systems. In such cases a great deal of rocket effluents should be released in the atomosphere. But, its effects on our environment is still unknown, and therefore various studies on these problems are expected. About such environmental problems, some studies were performed which motivated by so called “ionospheric hole” observed when Skylab-I was launched, May 14, 1973. It was certified by later scientific studies that the phenomenon was caused by the chemical reaction between rocket effluents and ionized particles in the ionosphere, by which the electron density of the ionosphere suddenly decreased to about a half values of that in its normal state in the range of about 1, 000km in radius centering about rocket trajectory and it took about 4 hours to recover. In this study, the results of these fundamental studies are applied to the engineering problem, that is, the numerical simulation of the change in electron density in the ionosphere is carried out in consideration of the diffusion of rocket effluents released along arbitrary trajectory in upper atomosphere and their chemical reactions with the ionospheric constituents.

Stratospheric cloud micro‐layers and small‐scale temperature variations in the Arctic in 1989

Thin layers of large (r ≈ 2–3 μm) particles were observed in the Arctic between 14 and 27 km on 23 and 30 January 1989. Although the particle mass is consistent with the available HNO3 vapor, it is not always clear whether the morphology of the layers is the result of recent condensation or evaporation as the layers appear under conditions of both supersaluration and undersaturation with respect to nitric acid trihydrate (NAT). Large amplitude, small vertical scale temperature variations appear to be associated with the layers but not in a simple manner. In regions supersaturated with respect to NAT, condensation on only a few of the available condensation nuclei takes place. Such preferential condensation into thin large particle layers suggests that this class of nuclei may be different than the previously assumed sulfate aerosol nuclei. The possibility that they may be derived from solid fuel rocket effluent and spacecraft ablation products is examined and cannot be excluded. Such a source may explain the appearance of these cloud layers at high altitude.

Changes in Electromagnetic Properties of the Upper Atmosphere due to Rocket Effluents

Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.

Comments on “Rocket Effluent: Its Ice Nucleation Activity and Related Properties”

Parungo and Allee (1978) reported ice nucleus (IN) measurements made from an aircraft in stabilized ground clouds from Titan III launches at KSC. They concluded from the measurements that the SGC contained IN. After an examination of the data the present authors (Hindman and Lala) argue that the filter devices were unable to detect IN in the SGC. In a reply Parungo and Allee attempt to refute this conclusion.

Opportunity to observe a large‐scale hole in the ionosphere

Since the earliest days of the U.S. Space Program, concerns have been raised regarding the atmospheric perturbations that might be caused by the exhaust products of large rocket engines. In 1964 a comprehensive review of the subject was published by Kellogg [1964] in which the space science community was alerted to the many possible ways that rocket ‘pollutants’ could have environmental impacts. The final impression left by Kellogg's paper was that the terrestrial atmosphere was sufficiently dense to absorb any conceivable shock that an aerospace technology might reasonably be expected to build—even to the point of the giant Saturn V rockets envisioned for the Apollo Program.In the 15 years that have passed since Kellogg's assessment, very little evidence was found to suggest that rocket effluents were in fact perilous to our environment. A reappraisal of all published accounts of rocket‐induced modifications of the atmosphere since Sputnik 1 (M. Mendillo, unpublished manuscript, 1979) reveals that hardly a dozen accounts exist describing specific aeronomic perturbations associated with the many hundreds of rocket launches that have occurred since 1957. There are good reasons for this: (1) The vast majority of rockets launched in the last 2 decades were relatively small ones, and thus the exhaust emissions amounted to no more than very minor additions of essentially trace species. (2) Of the large rockets (Saturns, Atlas/Centaurs, SL‐4/Soyuz) the overwhelming majority of launches carried payloads into low earth orbit (h < 200 km), where the typical exhaust products (H20, H2, CO2, N2, and O2,) were again relatively inconspicuous additions to ambient conditions. (3) Large‐rocket launches made by U.S. agencies generally occur at the Kennedy Space Flight Center, thereby insuring that rocket ascent trajectories occur over water—conditions hardly conducive to atmospheric monitoring via ground‐based facilities.

Electrets Used in Measuring Rocket Exhaust Effluents from a Space Shuttle Model

The study evaluates the use of electrets as a new contamination-detecting device designed to assess the chemical composition of rocket effluents. Evaluation of electret effectiveness revealed that electrets have multipollutant-measuring capability, simplicity of deployment and rapidity of assessment. Advantages of electrets are small size, light weight and cost-effectiveness. It is shown that electrets compare favorably with other HCl measuring devices. In particular, the summary of the measured data from electrets and HCl detectors is within the limits of computed HCl concentrations from the NASA/MSFC multilayer diffusion model.

Rocket Effluent: Its Ice Nucleation Activity and Related Properties

To investigate the possibility of inadvertent weather modification from rocket effluent, aerosol samples were collected from an instrumented aircraft subsequent to the Voyager 1 and 2 launches. The aerosol's morphology, concentration, and size distribution were examined with an electron microscope. The elemental compositions of individual particles were analyzed with an X-ray energy spectrometer. Ice nucleus concentration was measured with a thermal diffusion chamber. The particles' physical and chemical properties were related to their ice nucleation activity. A laboratory experiment on rocket propellant exhaust was conducted under controlled conditions. Both laboratory and field experimental results indicated that rocket propellant exhaust can produce active ice nuclei and modify local weather in suitable meteorological conditions.