Exhaust Cloud Research Articles

The Whistler Traveling Wave Parametric Amplifier Driven by an Ion-Ring Beam Distribution from a Neutral Gas Injection in Space Plasmas

A new parametric amplifier model describes the observations of intensified whistler waves produced by a dedicated burn of the BT-4 engine on the Cygnus spacecraft during the NG-13 mission. Ground very low frequency (VLF) radio emissions at 25.2 kHz from a Navy NML transmitter in North Dakota were amplified by 20-30 dB during the Cygnus burn at 480-km altitude and recorded at 1060 km by the e-POP/RRI plasma wave receiver on the SWARM-E satellite. The amplification process starts with charge exchange between the exhaust molecules and the ambient O+ in the ionosphere to produce water vapor ions that spiral around the earth's magnetic field lines. This ion-velocity-ring distribution generates broadband, oblique-lower-hybrid (OLH) waves, which act as a pump for the parametric amplifier. The nonlinear ponderomotive force on the electrons causes the high-amplitude OLH pump to mix with the input whistler signal, yielding an OLH idler wave. Resonant mixing of the pump and idler electric fields promotes temporal growth in the amplitude of the whistler waves as they propagate through the exhaust cloud. The key features to rocket exhaust-driven amplification (REDA) process are broadband gain, bi-directionality along the magnetic field, pump depletion, phasing, and feedback. Pump depletion limits the intensity of the output whistler waves by wave energy conservation. The total wave energy is the electrostatic energy of the pump and idler lower hybrid waves plus the energy extracted by the propagating whistler signal. The whistler traveling wave parametric amplifier provides an efficient mechanism for active amplification of signals in space.

Simulated Dispersion of the Gas Released by the SpaceX Falcon9 Rocket Explosion

This Paper provides a qualitative analysis of the contaminant dispersion caused by the SpaceX Falcon 9 rocket accident at Cape Canaveral Air Force Station on 1 September 2016. To achieve this, the Model for Simulating Rocket Exhaust Dispersion and its modeling system were applied to simulate the dispersion of the contaminants emitted during the explosion of the Falcon 9 rocket. This modeling system is a modern tool for risk management and environmental analysis for the evaluation of normal and aborted rocket launch events, being also suitable for the assessment of explosion cases. It deals with the representation of the source term (formation, rising, expansion, and stabilization of the exhaust cloud), the simulation of the short-range dispersion (in the scale from minutes to a couple of hours), and the long-range and chemical transport modeling by integrating with the Community Multiscale Air Quality model and reading meteorological input data from the Weather Research and Forecast model. The results showed that the modeling system captured satisfactorily the phenomenon inside the planetary boundary layer.

The development of a new model to simulate the dispersion of rocket exhaust clouds

This study presents the development of a new model named MSRED, which was designed to simulate the formation, rise, expansion, stabilisation and dispersion of rocket exhaust clouds for short-range assessment, using a three-dimensional semi-analytical solution of the advection–diffusion equation based on the ADMM method. For long-range modelling, the MSRED was built to generate a ready-to-use initial conditions file to be input to the CMAQ model, as it represents the state-of-the-art in regional and chemical transport air quality modelling. Simulations and analysis were carried out in order to evaluate the application of this integrated modelling system for different rocket launch cases and atmospheric conditions, for the Alcantara Launching Center (ALC, the Brazilian gate to the space) region. This hybrid, modern and multidisciplinary system is the basis of a modelling framework that will be employed at ALC for pre- and post-launching simulations of the environmental effects of rocket operations.

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.

Smart Indoor Air Pollution Monitoring System using Internet of Things

The expression Pollution by and large alludes to the open air pollution, chiefly brought about by burning of petroleum products by modern plants, exhaust cloud, and outflows from vehicles and trucks. Be that as it may, the air inside can likewise be dirtied. Indoor air pollution alludes to the sullying of indoor air. It might cause unsafe medical problems. The fundamental wellsprings of indoor air pollution are pesticides, stacks which contain toxins. Air quality has been to a great extent influenced by modern exercises, which have caused numerous medical problems among individuals. Air contaminations levels can be estimated utilizing gas sensors. Web of Things (IoT) innovation can be utilized to distantly distinguish pollution. IOT gadgets can be utilized to control fundamental capacities from anyplace around the globe through the internet.The information accumulated by such a framework can be communicated right away to an electronic application to empower checking constant information and permit impending danger management.The point is to fabricate a framework which can be utilized to screen the boundaries in various conditions. Here, we portray a whole Internet of Things (IoT) framework that gathers ongoing information in explicit areas. This ongoing information gathered is contrasted and a foreordained edge. This information is sent to the concerned association telling them about the qualities surpassing the edge assuming any and take fundamental activities if necessary.

Simulation of Rocket Exhaust Clouds at the Centro de Lançamento de Alcântara Using the WRF-CMAQ Modeling System

In this work we report numerical simulations of the contaminant dispersion and photochemical reactions of rocket exhaust clouds at the Centro de Lancamento de Alcântara (CLA) using the CMAQ modeling system. The simulations of carbon monoxide (CO), hydrogen chloride (HCl) and alumina (solid Al2O3) pollutants emission represent an effort in the construction of a computational tool in order to simulate normal and/or accidental events during rocket launches, making possible to predict the contaminant concentrations in accordance with emergency plans and pre and post-launchings for environmental management. The carbon monoxide and the alumina concentrations showed the formation of the ground and contrail cloud. The results also showed that hydrogen chloride concentrations would be harmful to human health, demonstrating the importance of assessing the impact of rocket launches in the environment and human health.

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

On-orbit firings of both liquid and solid rocket motors provide localized disturbances to the plasma in the upper atmosphere. Large amounts of energy are deposited to ionosphere in the form of expanding exhaust vapors which change the composition and flow velocity. Charge exchange between the neutral exhaust molecules and the background ions (mainly O+) yields energetic ion beams. The rapidly moving pickup ions excite plasma instabilities and yield optical emissions after dissociative recombination with ambient electrons. Line-of-sight techniques for remote measurements rocket burn effects include direct observation of plume optical emissions with ground and satellite cameras, and plume scatter with UHF and higher frequency radars. Long range detection with HF radars is possible if the burns occur in the dense part of the ionosphere. The exhaust vapors initiate plasma turbulence in the ionosphere that can scatter HF radar waves launched from ground transmitters. Solid rocket motors provide particulates that become charged in the ionosphere and may excite dusty plasma instabilities. Hypersonic exhaust flow impacting the ionospheric plasma launches a low-frequency, electromagnetic pulse that is detectable using satellites with electric field booms. If the exhaust cloud itself passes over a satellite, in situ detectors measure increased ion-acoustic wave turbulence, enhanced neutral and plasma densities, elevated ion temperatures, and magnetic field perturbations. All of these techniques can be used for long range observations of plumes in the ionosphere. To demonstrate such long range measurements, several experiments were conducted by the Naval Research Laboratory including the Charged Aerosol Release Experiment, the Shuttle Ionospheric Modification with Pulsed Localized Exhaust experiments, and the Shuttle Exhaust Ionospheric Turbulence Experiments.

Optical Emissions Observed During the Charged Aerosol Release Experiment (CARE I) in the Ionosphere

The in-flight engine firing of solid rocket motors in the ionosphere produces an artificial dusty plasma. Optical emissions of sunlight scattered from the dust particles yield measurements of the dust location and flow velocities. Charging by ambient ionospheric electrons of the particulates yields dust particles that stream across the magnetic field lines. These exhaust particles initiate plasma turbulence in the ionosphere that can scatter radar waves. If the exhaust cloud itself passes over in situ particle or plasma wave detectors, measurements can be made of increased dusty plasma wave turbulence and plasma densities. To demonstrate long-range detection of rocket engine burns in the ionosphere, the Charged Aerosol Release Experiment (CARE I) was conducted in September 2009. Optical observations from CARE I provided measurements of both the dust particle distributions and the interactions of the molecular component of the rocket exhaust in the ionosphere.

A multilayer model to simulate rocket exhaust clouds

This paper presents the MSDEF (Modelo Simulador da Dispersao de Efluentes de Foguetes, in Portuguese) model, which represents the solution for time-dependent advection-diffusion equation applying the Laplace transform considering the Atmospheric Boundary Layer as a multilayer system. This solution allows a time evolution description of the concentration field emitted from a source during a release lasting time t r , and it takes into account deposition velocity, first-order chemical reaction, gravitational settling, precipitation scavenging, and plume rise effect. This solution is suitable for describing critical events relative to accidental release of toxic, flammable, or explosive substances. A qualitative evaluation of the model to simulate rocket exhaust clouds is showed.

In Situ Measurement of Hydrochloric Acid in Rocket Exhaust Clouds Using a Remotely Piloted Aircraft

Abstract An instrumentation system employing an RPV (remotely piloted vehicle) platform was developed for temporally and spatially resolved air pollution measurements, and was used to measure the evolution of gas-phase HC1 in exhaust clouds from a solid rocket motor firing and fuel pit burns. A thermistor and a sensitive (ppmv-level), rapid-response (<0.1 sec) infrared absorption sensor for HC1 were mounted in a flow channel in the RPV, permitting concentration and temperature measurements to be made in the cloud on a several-meter scale. The RPV system was flown in a series of field tests at Thiokol Corporation’s Elkton, MD division to evaluate the HC1 content of the exhaust products of a new Mg-based fuel formulation. Measurements were made in the clouds from Al-based and Mg-based solid fuel pit burns and a Mg-fueled motor firing over periods of several minutes. Elevated temperatures and HC1 concentrations were found to be temporally correlated with video images of the particulate cloud. Cl originating ...

Using a geographical information system for monitoring space shuttle launches: Determining cumulative distribution of deposition and an empirical test of a spatial model

Space shuttle launches produce localized hydrochloric acid deposition. The interaction of solid rocket motor exhaust and deluge water released on the pad at the time of launch results in the formation of an exhaust cloud. The spatial pattern and extent of deposition from the launch cloud are predicted by the rocket exhaust effluent diffusion (REED) model. The actual pattern of deposition has been mapped by field surveys for each shuttle launch since 1981. In this paper we use a geographical information system (GIS) to compare model predictions with ground patterns for 49 shuttle launches. We also compile cumulative maps of deposition patterns needed to consider long-term impacts. The direction of launch cloud movement did not differ significantly from model predictions. The REED model overpredicted both the area that received deposition and the maximum distance from the launch pad that deposition occurred. Severe vegetation damage was restricted to near-field deposition areas within 1980 m north of each launch pad. Total area impacted from launches has been 87.0 ha around pad 39A and 52.9 ha around pad 39B. Far-field deposition has caused leaf spotting from acid droplets or aluminum oxide over a wider and more variable area than near-field. A total of 19,397 ha has received deposition, but 63.6% of this area has received deposition only one time and 92.2% not more than three times. GIS techniques provide means to test spatial models and compile information useful for assessing cumulative impacts.

Hydrogen chloride vapor pressure over metal chloride aerosols from rocket exhausts

The importance of chloride coatings in determining the atmospheric properties of solid fuel exhaust particles is examined using a rigorous thermodynamic treatment of HC1-A1C1 3-H2O and HCl-BeCl2-H2O mixtures. Although chloride salts represent only about 5% of the mass of the particles, their hygroscopic nature means that they dominate the control of the liquid water content of exhaust clouds with low water vapor content. In the presence of chloride particles, liquid water and dissolved HC1 persist over a wider range of conditions than in a pure HC1-H2O cloud. An equilibrium model of HC1 partitioning in the Space Shuttle exhaust cloud satisfactorily represents the measured distributions and suggests that cloud lifetime is a function of ambient relative humidity. Beryllium chloride particles show similar properties to those of aluminum.

Surface composition of solid-rocket exhausted aluminum oxide particles

Particulate samples of aluminum oxide were collected on Teflon filters from the exhaust plume of the Space Shuttle (STS-61A, October 30, 1985) over the altitude interval 4.6-7.6 km immediately after launch. These particles were analyzed using SEM, energy-dispersive X-ray analysis, electron spectroscopy for chemical analysis, X-ray fluorescent spectroscopy, and conventional wet-chemical techniques. The samples were 0.6-1.0 percent surface-chlorided (chlorided meaning predominantly aluminum chlorides and oxychlorides, possibly including other adsorbed forms of chloride) by weight. This level of chloriding is about one-third of the amount determined previously from laboratory-prepared alumina and surface site samples of solid-rocket-produced alumina (SRPA) after both had been exposed to moist HCl vapor at temperatures down to ambient. This level is equivalent to previous laboratory results with samples exposed to moist HCl at temperatures above the boiling point of water. It is suggested that the present lower chloriding levels, determined for samples from a 'dry' Shuttle exhaust cloud, underscore the importance of a liquid water/hydrochloric acid phase in governing the extent of surface chloriding of SRPA. The reduced chloriding is not trivial with respect to potential physical/chemical modification of the SRPA particle surfaces and their corresponding interaction with the atmosphere.

An Analysis of Particulate Removal from the TITAN Rocket Exhaust Cloud

Abstract A simplified analytical model is developed to analyze the removal of A12O3 particles from the TITAN rocket exhaust cloud. The model incorporates the physical processes of deposition and impact collection and includes consideration of particle size spectra. Results of computations are in good agreement with the measurements and show that sedimentation plays the most important role in the removal of the mass of material in the elevated ground cloud within the first hour after launch. The model allows for easy estimates of airborne concentrations and sedimentation when relevant sounding, exhaust mass and estimates of initial particle size distribution data are available.

Airborne measurements of Space Shuttle exhaust constituents

Airborne measurements of hydrogen chloride (HCl) and particulates made during penetrations into and flights under Space Shuttle exhaust clouds from launches STS-1, -2, and -5 are presented to permit comparison with dispersion model predictions for Space Shuttle exhaust clouds, and with previous measurements made in Titan III exhaust clouds. Analytical techniques employed for the Shuttle measurements were developed and refined during earlier Titan III exhaust cloud measurements and include the measurements of particulate concentrations, size distributions, and the partitioning of HCl between the gaseous and aerosol phases. The results are useful in understanding the dynamics of ground cloud development, atmospheric dispersion, and potential environmental effects of Shuttle effluents.

Hydrogen chloride and aerosol ground cloud characteristics resulting from space shuttle launches

Airborne measurements of gaseous HCl, gaseous and aerosol HCl, particulates, relative humidity and temperature were obtained in ground clouds produced during three Space Shuttle launches. Partitioning of HCl between HCl aerosol and gaseous HCl was investigated as the solid rocket exhaust cloud diluted with ambient air to evaluate the conditions under which aerosol formation occurs in the troposphere in the presence of hygroscopic HCl vapor. Equilibrium predictions for aqueous HCl aerosol formation generally agree with the measured HCl partitioning over HCl concentrations from 0.5 to 36 ppm. HCl concentration dispersion within four cloud segments at time t (min) was evaluated using the expression C = C 0t α where C 0 varied from 145 to 2250 ppm and α varied from −1.14 to −1.73. Aerosol fallout from the exhaust clouds was measured with time by monitoring HCl concentrations and aerosol distributions 100 m below the cloud as it drifted away from the launch site. Significant amounts of HCl were found to be removed by fallout of particles in the 80–220 μm diameter range up to 30 min after launch.

Incoherent scatter observations of an artificially modified ionosphere

The launch of NASA's HEAO‐C satellite by an Atlas/Centaur rocket on September 20, 1979, provided the first “experiment of opportunity” to test incoherent scatter radar techniques for the diagnostic study of a chemically‐induced modification of the ionosphere. The cause of the disturbance was the rocket's exhaust cloud of H2 and H2O molecules that cause a rapid recombination of the F region plasma at heights above 250 km. The launch from the Kennedy Space Center (28°N, 81°W) was monitored by the incoherent scatter radar at Millstone Hill (42.6°N, 71.5°W) using low elevation angle observations over ranges exceeding 2000 km. The experiment employed various pulse lengths, integration times and scanning modes to explore optimization methods for an upcoming series of Space Shuttle induced ionospheric hole experiments. The results from the HEAO‐hole campaign include the first unambiguous observations of a gas expansion “snowplow effect,” the derivation of local and height‐integrated plasma recombination rates, and the full spatial, temporal, and dynamical morphologies of a large‐scale ionospheric hole. The campaign succeeded in demonstrating that incoherent scatter radars can play a primary role in space plasma physics “active experiments” during the next decade.

HCI in Rocket Exhaust Clouds: Atmospheric Dispersion, Acid Aerosol Characteristics, and Acid Rain Deposition

NASA is examining Space Shuttle launch impacts. Solid rocket exhaust includes ˜60 tons HCL and ˜87 tons alumina particles emitted below 2.5 km, of which 50-80% forms an altitude stabilized exhaust cloud (EC). Several 60% smaller Titan-Ill EC were sampled by aircraft for this study. Three distinct features are presented: (a) An analysis of HCL (gaseous plus aqueous) data traces. Total range of peak HCL was 25-0.5 ppm (3-300 min) for 8 EC. Power-law decays of peak HCL applied. Calculated HCL dispersions for 7 standard meteorologies are also shown, (b) An analysis of simultaneous HCL (g), HCL (g + aq) data for 2 EC. Vapor-liquid HCL/H2O equilibria were calculated for a flat surface aqueous aerosol. HCL partitioning varied with EC dilution and H2O content. HCL (aq) and aqueous mass fraction maximized early at >3 molal and >0.1 mg/g air. Calculated H2O (g + aq) compared favorably with independent EC measurements, (c) An analysis of wet deposition after EC interception at ˜30 min by a convective storm. A 28 km2 acid chloride (1 < pH < 3) footprint was defined. In conclusion, (a) HCL dispersion in large EC tends to follow power-law decay, but HCL concentration may vary widely (100 times after 1 h) with meteorology, (b) HCL (g/aq) and H2O (g/aq) partitioning is consistent with equilibrated acid aerosol compositions, and (c) localized deposition of highly acidic rain may occur sometimes.

Interaction of gaseous hydrogen chloride and water with sandy soil

The adsorption of hydrogen chloride and water vapor on sandy soil has been studied. Characterization of the soil was performed using scanning electron microscopy (SEM), particle size distribution, neutron activation analysis, BET nitrogen surface area measurements, and electron spectroscopy for chemical analysis (ESCA). Water vapor and hydrogen chloride adsorption isotherms at 30°C were measured on soil after outgassing at 100°C. The heats of immersion of the soil outgassed at 100°C were determined in both water and 0.1 N hydrochloric acid solution to complement the vapor-phase measurements. ESCA spectra of soil were obtained before and after exposure to hydrogen chloride. The results are compared with similar measurements on a-quartz. The acidity of soil slurries was measured as a function of time on addition of HCl(aq) to various size fractions. Implications regarding possible roles of sandy soil entrained in solid rocket exhaust clouds are discussed.

Hydrochloric acid aerosol and gaseous hydrogen chloride partitioning in a cloud contaminated by solid rocket exhaust

Partitioning of hydrogen chloride between hydrochloric acid aerosol and gaseous HC1 in the lower atmosphere was experimentally investigated in a solid rocket exhaust cloud diluted with humid ambient air. Airborne measurements were obtained of gaseous HCl, total HCl, relative humidity and temperature to evaluate the conditions under which aerosol formation occurs in the troposphere in the presence of hygroscopic HCl vapor. Equilibrium predictions for HCl aerosol formation accurately predict the measured HCl partitioning over a range of total HCl concentrations from 0.6 to 16 ppm.