Small Rocket Research Articles

Shape optimization of cantilevered columns subjected to a rocket-based follower force and its experimental verification

Intended aims of the paper are, firstly to conduct a realistic structural optimization of a nonconservative system, and secondly to give an experimental verification of the theoretically predicted stabilizing effect of shape optimization of cantilevered columns subjected to a rocket-based follower force. Flutter of a cantilevered column having a small solid rocket motor at its free end is considered in this paper. The shape optimization for maximum flutter load was conducted computationally with the design constraint that the width of the column should not be less than half of the initial width, in order to keep test-pieces elastic during compressive loading. The theory predicts that the flutter parameter of the shape optimized column with constant volume can be 1.2 times higher than that of the uniform column. Then the corresponding experiment was conducted. The mean thrust produced by the rocket motor was assumed constant during firing. As the applied load in the experiment was constant the free parameter for loading was the length of the columns. The mean thrust was 580 N and the burnout time was 3.2 s. Five test runs were conducted to find the experimental critical length of the uniform test columns. Following this, two runs were made with optimum columns having the same lengths as the corresponding uniform test columns. As the outcome, an experimental verification was given to structural optimization of cantilevered columns subjected to a rocket-based follower force.

System Development of an Experimental Rocket and an Autonomous Free Falling Mobile Robot

This paper presents the development of a small experimental rocket for the National Launching Campaign held by the DGAEM in France since 2009. The campaign organized by CNES was conducted by the French Association of Planete Sciences. The rocket design was developed by Space Club Gifu and Sasaki Lab at Gifu University. The main mission is the autonomous navigation of a quasi-satellite maneuvering with a parachute and two propellers to a target point using GPS data. The rocket is 2m long, 150mm in diameter, weight 11.4kg and made entirely of CFRP. With a solid rocket motor provided by CNES, the rocket can reach an altitude of 840m. Onboard are a pressure sensor, accelerometer, GPS and two video cameras. The video cameras begin monitoring at launch. The acceleration, velocity and position were recorded for later comparison to simulation data. While the rocket launch and quasi-satellite deployment were successful, strong winds prevented the latter from maneuvering to the target point. All components were recovered intact and all recorded data were available for analysis.

Numerical Simulation of the Spray Characteristics in Small Scale Liquid Rocket Engine Combustion Chamber

The mathematical and physical model of the liquid propellant spray in straight nozzle was proposed for studying the performance characteristics of the small-scale liquid rocket engine. With the Fluent software, the numerical simulation was carried out. Sauter mean diameter (SMD) of the HAN-based liquid propellant (LP1846) in the engine combustor changing with spray pressure, nozzle diameter and the liquid surface tension were analyzed. The results indicate that: in the spray pressure region of 1.8MPa~3.0MPa, at a fixed spray pressure, the smaller is the nozzle diameter, the smaller is the droplets’ SMD and the relationship between the SMD and the nozzle diameter is approximately linearity; for the same nozzle diameter and spray pressure, the larger is the surface tension, the larger is the liquid droplets’ SMD.

S1901-2-5 ハイブリッドエンジン搭載型小型有翼ロケットの飛行実験(小型宇宙システム(2),社会変革を技術で廻す機械工学)

S1901-2-5 ハイブリッドエンジン搭載型小型有翼ロケットの飛行実験(小型宇宙システム(2),社会変革を技術で廻す機械工学)

S1901-2-2 小型ハイブリッドロケット打上げとプロジェクト遂行型教育への適用(小型宇宙システム(2),社会変革を技術で廻す機械工学)

S1901-2-2 小型ハイブリッドロケット打上げとプロジェクト遂行型教育への適用(小型宇宙システム(2),社会変革を技術で廻す機械工学)

Development of Non-Combustible Rocket Engine by Using Explosive Boiling of Liquid Nitrogen

Recently, the activity of the development of a small rocket in universities has been enhancing. Focusing on safety, we have been developing a small rocket engine using two liquids (LN2 and H2O) without combustion process. In order to improve reliability and performance of this engine, we developed the engine without a valve in a LN2 passage. In this engine system, initial water temperature and GN2 pressure were changed within the ranges of 100-170°C and 1.0-2.0 MPa for reducing weight of water and getting higher performance. Thrust was increased with increasing the initial water temperature because the flow rate of H2O was decreased with increasing the water temperature. In addition, thrust was increased with decreasing the GN2 pressure under these experimental conditions. As a result, the ratio of LN2 and H2O weight could be reduced from 3:4 to 1:1. The relation between the mixing chamber pressure and an initial water temperature was very important for reducing of amount of fuel.

Ablation Characteristic of 3D C/SiC Composite Nozzle in a Small Solid Rocket Motor

Ablation properties of a 3D C/SiC composite nozzle were investigated by using hot-firing test in a small solid propellant rocket motor.Ablation mechanisms of the C/SiC composites and effects of the combustion gases parameters were discussed.The results show that the linear ablation rate at the throat of the composite nozzle is 0.128±0.088mm/s,and the mass ablation rate is 0.166kg/(m~2.s). Ablation behavior for the 3D C/SiC composite shows a nonuniform process,which is directly affected by the compositions,temperature,pressure and the velocity of combustion gases.The ablation in the divergent section,convergent section and the regions near the throat grows severe by degrees. Ablation mechanisms of C/SiC composite are the cooperation of thermo-physical ablation,thermo- chemical ablation and thermo-mechanical erosion,which involve the decomposition of the SiC,oxidation of the SiC and carbon fiber,as well as chemical and mechanical erosion by Al_2O_3 slags and particles, respectively.

G26 小型の有翼式ロケット実験機と予備飛行実験結果(G2 機械力学(移動体の制御))

G26 小型の有翼式ロケット実験機と予備飛行実験結果(G2 機械力学(移動体の制御))

Development of CAMUI hybrid rocket to create a market for small rocket experiments

By introducing various innovative ideas, the difficult-to-develop small hybrid-type rocket is successfully developed. The main purpose is to drastically reduce the cost of rocket experiments and thus, attract potential users such as metrological and microgravity researchers. A key idea is a new fuel grain design to accelerate the gasification rate of solid fuel. The new fuel grain design, designated as CAMUI as an abbreviation of “cascaded multistage impinging-jet”, is that the gas flow repeatedly collides with the solid fuel surface to accelerate the heat transfer to the fuel. To install a regenerative cooling system using cryogenic liquid oxygen as coolant in a small launcher, the authors devised a valveless supply system (with no valves in the liquid oxygen flow line). Four serial successful launch verification tests by 10 kg vehicle equipped with a 50 kgf thrust CAMUI motor have shown the feasibility of the motor system. The meteorological observation model of 400 kgf class motor is under development and the development of microgravity experiment class of 1.5–2 tonf motor will follow subsequently. The authors plan to complete the development of the 400 kgf class motor for meteorological observation model by the end of FY2005.

Current Status of Rocket Developments in Universities -Development of a Small Rocket without Combustion Process

Current Status of Rocket Developments in Universities -Development of a Small Rocket without Combustion Process

Computational Analysis of an Independent Ramjet Stream in a Combined Cycle Engine

A new concept for the low-speed propulsion mode in rocket-based combined cycle engines has been developed as part of the NASA GTX program. This concept, called the independent ramjet stream (IRS) cycle, is a variation of the traditional ejector ramjet (ER) design and involves the injection of hydrogen fuel directly into the airstream, where it is ignited by the rocket plume. The advantage of the IRS design is that it allows for a single large rocket instead of several smaller rockets, and its required combustor length is smaller than that of a traditional ER design. Both of these features make the IRS design lighter. Experiments and computational fluid dynamics are currently being used to evaluate the feasibility of the new design. In this work, a Navier‐Stokes code valid for general reactive flows is applied to the model engine under cold-flow, ER, and IRS cycle operation. Pressure distributions corresponding to cold-flow and ER operation are compared with experimental data. The engine response under IRS cycle operation is examined for different reaction models and grid sizes. The solutions exhibit a high sensitivity to both grid resolution and reaction mechanism but do indicate that thermal throat ramjet operation is possible through the injection and burning of additional fuel into the airstream.

Desempenho da cultura da rúcula cultivada em época de verão em túneis baixos de polietileno perfurado

O túnel baixo é um tipo de ambiente protegido utilizado, principalmente, em cultivo de espécies de pequeno porte, como alface, morango, pimentão, rúcula e pepino. Por serem estruturas de menor porte, apresentam menor custo de instalação em relação ao túnel alto. A presença de material plástico em sua cobertura proporciona um ganho térmico durante o dia, facilitando o crescimento das plantas, protegendo as culturas do impacto da chuva, dos ventos frios e das temperaturas mínimas. Esta pesquisa teve o objetivo de avaliar o efeito de filme de polietileno com diferentes intensidades de perfurações (0; 5; 10; 15 e 20%), no microclima em túneis baixos e no desenvolvimento da cultura da rúcula (Eruca vesicaria sativa (Mill) Thell) em época de verão. Os resultados mostraram que houve diferença de produtividade entre os túneis com diferentes níveis de perfuração e houve diferenças significativas quanto às características físicas da planta em alguns tratamentos comparativos à testemunha. Quanto aos aspectos relacionados com o microclima, verificou-se, por meio de análise estatística, que a temperatura do ar observada nos horários mais críticos do dia (11 às 15 h) apresentou diferenças significativas entre o ambiente coberto com túnel sem perfuração e o solo descoberto; com relação à umidade absoluta do ar, quanto maior o nível de perfuração do plástico de cobertura do túnel, menor a umidade absoluta observada.

Modeling of Chemically Reacting Flowsfrom a Side Jet at High Altitudes

The interaction of a jet from a 60-lbf (267-N) thruster positioned on the side of a small rocket, with the rarefied atmosphere between altitudes of 80 to 160 km, is studied numerically. A multistep approach is employed, which combines the successive computation of the flow inside the thruster using a Navier‐Stokes solver, the axisymmetric plume core flow, and chemically reacting three-dimensional plume-atmosphere interaction using the direct simulation Monte Carlo method, and obtains the UV radiation fields based on the flow solution. The impact of the boundary layer inside the nozzle as well as the rocket speed (5‐8 km/s) and flight altitude (80‐160 km) on the plume-atmosphere interaction is examined. I. Introduction A TMOSPHERIC interceptor (AI) vehicles currently being developed use divert and attitude reaction control systems (RCS) to perform quick maneuvers during flight. The forward and aft RCS engines provide the thrust for attitude (rotational) maneuvers (pitch, yaw, and roll) and for small velocity changes along the rocket axis (translation maneuvers). In the past few years extensive experimental and theoretical studies have been undertaken to predict RCS jet interactions with the ambient atmosphere accurately. Although significant progress has been achieved in understanding the phenomenology of the jet-atmosphere interaction, several important problems still need to be resolved, particularly with regard to supersonic and hypersonic flows at low and high altitudes. Experimental measurements have been made to characterize the jet-atmospheric interaction in wind-tunnel facilities. However, it is difficult to scale these results 1 to flight conditions because of freestream/plume chemistry, Reynolds number, surface, and wall interference effects. Computational studies are therefore necessary to supplement and expand experimental efforts and obtain credible information on performance characteristics and flowfield structure of RCS thrusters at different altitudes. At low altitudes (up to about 60 km) the freestream-jet interaction is characterized by thin plume and bow shock waves and a jet-induced separation region in front of the divert thruster side jet. 2 The flow separation is responsible for the elevated pressure in this region and corresponding thrust amplification and might also affect the operation of optical sensors located upstream from the nozzle. 3,4 The problem of sensor contamination was considered in Ref. 5. AI vehicle aerodynamics and thruster performance at low altitudes were examined numerically by several workers, mostly using solutions of the Navier‐Stokes equations. 6−9 The jet-atmosphere interaction at high altitudes is qualitatively different from that at low altitudes. The flow separation in front of the jet becomes less pronounced and diminishes at altitudes 80 km and higher, and the effect of the atmosphere on the plume is much weaker. Because of the rarefaction, the jet interaction impact on the vehicle aerodynamics is significantly smaller. The direct simulation Monte Carlo (DSMC) method was used in Ref. 10 to compute the three-dimensional jet interaction for a corner flow configuration,

Design, construction and testing of a low‐cost hybrid rocket motor

Small hybrid rocket motors using solid propellant and gaseous oxidizer are becoming increasingly popular as a propulsion device. This paper describes the development of a one‐dimensional flow model for the design of a small rocket motor. Combustion of polyethylene as solid propellant with oxygen is used as a candidate hybrid fuel to test and evaluate the performance of this hybrid system. To assess the performance under different operating conditions, a computer program has been developed, which facilitates inputs to be varied and effects assessed. A system of governing equations is summarized in the main body of this paper and is numerically solved by the computer program. The results of the modelling are then used to design and build a small low‐cost rocket motor for experimental verification. Therefore, the materials presented herein could be used in the future design of hybrid rocket motors.

In situ measurements of carbon dioxide, 0.37–4.0 μm particles, and water vapor in the stratospheric plumes of small rockets

Carbon dioxide (CO2) and large particles (0.37–4.0 μm) were measured in the stratospheric plume wakes of three rockets, an Atlas IIAS, a Delta II, and an Athena II. The correlations between CO2 mass and particle number densities in each plume are consistent with the unique combination of solid and liquid engine emissions of each rocket. Measured size distributions indicate a 1.1 μm mode with density of 2 g cm−3, consistent with spherical alumina particles emitted by solid rocket motors. Disagreement between the measured size distributions and the mean sizes inferred from the known alumina and CO2 emission indices and an observed increase in the particle number emission index with altitude are evidence for large particle oversampling effects and the presence of condensed volatile compounds within the particle population. Direct evidence for the latter is a persistent ∼0.5–1 part per million (ppm) shortfall of water vapor relative to CO2 measured in the plume of the Athena II rocket based on the expected H2O/CO2 emission ratio. Although pure ice particles would not persist at the conditions of the measurements, a more stable coating of HNO3 (as either nitric acid trihydrate or as a liquid layer) could have reduced the sublimation rate of the underlying ice, thereby increasing the lifetimes of volatile particles within the plume. If confirmed, such a process would have important implications for the radiative and chemical properties of rocket plumes, including global ozone depletion associated with rocket launch activities.

Measurements of water vapour in the mesosphere with the spectral absorption line imager (SALI)

Water vapour concentration is one of the most important, yet one of the least known quantities of the mesosphere. Knowledge of water vapour concentration is the key to understanding many mesospheric processes, including the one that is primary focus of our investigation, Polar Mesospheric Clouds (PMC). The processes of formation and occurrence parameters of PMC constitute an interesting problem in their own right, but recent evidence had been provided which suggests that PMC are a critical indicator of climate change. In this context the feasibility of a low cost method of water vapour measurements using an instrument carried aloft by a sounding rocket has been examined and some of the results discussed. It is proposed to measure the strength of the 936nm water absorption line in a solar occultation configuration employing a CCD detector. This leads to the design of a small, low cost and low-mass instrument, which can be flown on a small rocket, of the type of the Orbital Sciences Corporation Viper 5. Alternatively the instrument can be flown as a “passenger” on larger rocket carrying other experiments. In either case flight costs are relatively low. Some performance simulations are presented showing that the instrument we have designed will be sufficiently sensitive to measure water vapor in concentrations that are expected at the summer mesopause, about 85 km height. Sufficient payload design work was carried out showing that the structural, thermal and electrical requirements for a flight on the Viper 5 rocket can be met and thus making the experiment feasible for a flight.

Electron beam interaction with space plasmas

Active space experiments involving the controlled injection of electron beams and the formation of artificially generated currents can provide in many cases a calibration of natural phenomena connected with the dynamic interaction of charged particles with fields. They have a long history beginning from the launches of small rockets with electron guns in order to map magnetic fields lines in the Earth's magnetosphere or to excite artificial auroras. Moreover, natural beams of charged particles exist in many space and astrophysical plasmas and were identified in situ by several satellites; a few examples are beams connected with solar bursts, planetary foreshocks or suprathermal fluxes traveling in planetary magnetospheres. Many experimental and theoretical works have been performed in order to interpret or plan space experiments involving beam injection as well as to understand the physics of wave-particle interaction, as wave radiation, beam dynamics and background plasma modification. Recently, theoretical studies of the nonlinear evolution of a thin monoenergetic electron beam injected in a magnetized plasma and interacting with a whistler wave packet have led to new results. The influence of an effective dissipation process connected with whistler wave field leakage out of the beam volume to infinity (that is, effective radiation outside the beam) on the nonlinear evolution of beam electrons distribution in phase space has been studied under conditions relevant to active space experiments and related laboratory modelling. The beam-waves system's evolution reveals the formation of stable nonlinear structures continuously decelerated due to the effective friction imposed by the strongly dissipated waves. The nonlinear interaction between the electron bunches and the wave packet are discussed in terms of dynamic energy exchange, particle trapping, slowing down of the beam, wave dissipation and quasi-linear diffusion.

Parametric studies of the Hall current plasma thruster

The Hall current plasma thruster accelerates a plasma jet by an axial electric field and an applied radial magnetic field in an annular ceramic channel. A relatively large current density (>0.1 A/cm2) can be obtained as the acceleration mechanism is not limited by space charge effects. Such a device can be used as a small rocket engine on board spacecraft with the advantage of a large jet velocity compared to conventional rocket engines (10000–30000 m/s versus 2000–4800 m/s). An experimental Hall thruster was constructed and operated in a broad range of operating conditions and under various configuration variations. Electrical, magnetic and plasma diagnostics, and as well accurate thrust and gas flow rate measurements, have been used to investigate the dependence of thruster behavior on the applied voltage, gas flow rate, magnetic field, channel geometry and wall material. The studies conducted so far have demonstrated a significant effect of channel material on thruster electrical characteristics and the existence of an optimal channel length for a given flow rate. Representative results highlighting these findings are presented.

Detection of a meteor contrail and meteoric dust in the Earth's upper mesosphere

In 1983 a series of small rockets were launched from the Poker Flat Rocket Range near Fairbanks, Alaska to study what has come to be called Polar Mesospheric Summer Echoes (PMSE). We report here on a fortuitous simultaneous 50-MHz radar and rocket detection of what seems to be a meteor contrail produced over the Poker Flat Rocket Range. The two data sets are mutually consistent and taken together suggest some very interesting properties for the trails of large meteors. Most notable is the first evidence that the ablated material can coagulate into particles the order of 50 nm in radius. This estimate is based primarily on the fall speed deduced from both the Doppler shift of the VHG radar signal and the time rate of change of the target as it fell through the beam. In addition the very existence of the radar target, the extremely sharp edges of the trail, and the existence of electron density structures inside the trail more than an order of magnitude smaller than the Kolmogorov microscale, all require large charged aerosols and a very high Schmidt number. Curiously the environment leading to PMSE (the study of which was our primary mission), is very similar to the properties of a large meteor trail some minutes after it is formed. In the PMSE case ice particles grow and become charged by the plasma and, when more than half the charge is tied up on the ice, the plasma diffusion coefficient becomes so small that structure can be supported at VHF scattering scales. In the late-time meteor case large aerosols coagulate and tie up both natural charge in the plasma and the original meteor trail electrons, Following the work of Rosinski and Snow (1961) and Hunten et al. (1980) we conclude that the incident meteor was the order of 100 g and would have had a visual magnitude of about - 5. This dust production process may resolve some open questions concerning long-lived meteor radar echoes. For example, in the event studied the electron density was well into the underdense condition and yet was detected for over 6 min. Classical meteor scatter theory has no explanation for such a long duration underdense event. c 1998 Elsevier Science Ltd. All rights reserved

State Spaceport Initiatives: Economic and Political Innovation in an Intergovernmental Context

State Spaceport Initiatives: Economic and Political Innovation in an Intergovernmental Context