Showing papers on "Rocket published in 1984"

Comparison of mesospheric VHF radar echoes and rocket probe electron concentration measurements

Abstract: Refractive index irregularities in the equatorial mesosphere have been investigated using both the Jicamarca VHF radar and a rocket-borne Langmuir probe launched from Punta Lobos, Peru. On February 27, 1983, a single layer of turbulence was observed in the upper mesosphere by both experiments. There is very good agreement between the observed radar echo power and the radar scattering cross section calculated from the rocket data when these are interpreted in the context of isotropic turbulence. The inner and outer scales of turbulence have been calculated from both the radar and the rocket data, and good agreement is found. The radar data show indications of large-scale vortices in the layer of irregularities. Rocket data show that the inner scale of turbulence in the upper mesosphere is a few tens of meters and that the Jicamarca radar Bragg wavelength (3 m) is well within the viscous subrange of turbulence in this altitude range. The spectral index in the inertial subrange is close to -5/3, changing to about - 7 at higher wave numbers. Energy dissipation rate in the layer was calculated to be 0.05 W/kg, in good agreement with previous estimates.

Spacecraft optimized arc rocket

Abstract: This invention relates to a thruster apparatus applicable to the environment of a space vehicle or satellite and operable for positioning such vehicle or satellite in the proper orbital location. The device utilizes a unique configuration of passageways to convey the propellant to a location adjacent an electrical arc forming device. The propellant, heated thereby, then travels out a nozzle section of the thruster to thereby produce thrust. If desired, an external heater may be provided to preheat the thruster to thereby contribute to greater efficiency in the use of propellant. Further, if desired, the thruster may include an accelerator extension.

Optimal low-thrust transfers to synchronous orbit

Abstract: The general problem of circle-to-circle transfer is examined for chemical rocket spacecraft, following Lawden's "primer vector" theory. Impulsive and near-impulsive transfers are analyzed to predict initial conditions for low-thrust transfers. A computer solution of the low-thrust problem is described. Results are presented for the low Earth orbit to geosynchronous orbit case, showing behavior of the optimal thrust direction, and developing transfer efficiency figures for a range of acceleration limits. Both fixed-thrust and fixedacceleration propulsion systems are considered. The effect of multiple burns is discussed. Robbins's approximation for gravity loss is shown to be good for a large class of maneuvers.

Influence of particulates on infrared emission from tactical rocket exhausts

Abstract: The influence of radiation scattering on the infrared radiation signature of representative plumes from four types of tactical rocket motors is investigated using the recently developed JANNAF Standardized Infrared Radiation Model (SIRRM) numerical code. The plumes are modeled as isothermal cylinders with gas and particle compositions representative of 1) advanced liquid rocket exhausts (HC1, HF/carbon); 2) low-temperatu re metal fuel solid rocket exhausts (H2O, HC1, CO/aluminum oxide); 3) reduced smoke low visibility solid rocket exhausts (H2O, HC1, CO, CO2/aluminum oxide); and 4) advanced minimum smoke solid rocket exhausts (CO, CO2, H2O/zirconium oxide). The signatures of the plumes containing carbon particles are sensitive to the amount of carbon present, but insensitive to the carbon particle size. The signatures of the plumes containing aluminum oxide particles are sensitive to both the particle size and the amount of aluminum oxide present. The emission from the advanced minimum smoke plume becomes increasingly sensitive to particle size and concentration as the particle loading increases.

Mixing, Chemical Reaction and Flow Field Development in Ducted Rockets

Abstract: Calculations have been made of the three-dimensional mixing, chemical reaction, and flow field development in a typical ducted rocket configuration. The governing partial differential equations are numerically solved by an iterative finite-difference solution procedure. The physical models include the k approx. epsilon turbulence model, one-step reaction, and mixing controlled chemical reaction rate. Radiation is neglected. The mean flow structure, fuel dispersal patterns, and temperature field are presented in detail for a base configuration with 0.058 m (2 in.) dome height, 45/sup 0/ side arm inclination, and with gaseous ethylene injected from the dome plate at an eccentric location. In addition, the influences of the geometrical parameters such as dome height, inclination of the side arms, and location of the fuel injector are studied.

Liquid fuel expulsion system

Abstract: An explusion system in which an inner tank is nested within a second and er tank to provide a very compact and space saving arrangement for an expulsion system for a rocket with the first and inner tank as well as the second and outer tank being reinforced with composite material to provide a space saving and relatively light expulsion system for a rocket.

Solid rocket motor with nozzle containing aromatic amide fibers

Abstract: A solid rocket motor is provided which comprises a rocket case and a centrally ported propellant grain comprising a main portion and a nozzle portion, wherein the main portion is a shaped and cured first propellant and wherein the nozzle portion comprises a shaped and cured second propellant composition having a lower burn rate than the first composition and having a plurality of aromatic amide fibers dispersed therethrough.

Flow processes in overexpanded chemical rocket nozzles. Part 2: Side loads due to asymmetric separation

Abstract: Methods for measuring the lateral forces, occurring as a result of asymmetric nozzle flow separation, are discussed. The effect of some parameters on the side load is explained. A new method was developed for calculation of the side load. The values calculated are compared with side load data of the J-2 engine. Results are used for predicting side loads of the space shuttle main engine.

Extendable tube for vertically delivered weapons

Abstract: An extendable rocket launcher tube for a rocket wherein releasable telescoped concentric inner and outer tubes house the rocket. Upon ignition, the rocket releases the inner tube from the outer tube and carries it forward imparting momentum thereto. The rocket is released from the inner tube at a selected axial extension of the inner tube. The components move at relative speeds such that acceleration of the rocket is complete when the launcher tube is fully extended.

Aircraft emergency landing system

Abstract: An emergency landing system for an aircraft, particularly a helicopter, in which a plurality of rocket members are mounted on the fuselage of the aircraft and directed downward about the center of gravity of the fuselage. The rocket members are activated to direct upward reactive forces by the energization of a proximity switch located on the fuselage and adapted to sense the ground level when the fuselage has descended within a predetermined elevation above the ground level so that the downward movement of a disabled aircraft is substantially decelerated to provide a soft landing for the aircraft. The landing system may be adapted for use on a fixed wing aircraft by directing the rocket members to exert reactive forces rearward as well as upward to retard the forward as well as downward movement of a disabled fixed wing aircraft.

Plug nozzle kinetic energy penetrator rocket

Abstract: A kinetic energy penetrator having a penetrator rod which is placed inside rocket propelled motor casing to become the major load carrying member of the airframe structure.

Flow processes in overexpanded chemical rocket nozzles. part 1: flow separation

Abstract: An investigation was made of published nozzle flow separation data in order to determine the parameters which affect the separation condition. A comparison of experimental data with empirical and theoretical separation prediction methods leads to the selection of suitable equations for the separation criterion. The results were used to predict flow separation of the main space shuttle engine.

Engineering aspect of the Microwave Ionosphere Nonlinear Interaction Experiment (MINIX) with a sounding rocket

Abstract: The Microwave Ionosphere Nonlinear Interaction Experiment (MINIX) is a sounding rocket experiment to study possible effects of strong microwave fields in case it is used for energy transmission from the Solar Power Satellite (SPS) upon the Earth's atmosphere. Its secondary objective is to develop high power microwave technology for space use. Two rocket-borne magnetrons were used to emit 2.45 GHz microwave in order to make a simulated condition of power transmission from an SPS to a ground station. Sounding of the environment radiated by microwave was conducted by the diagnostic package onboard the daughter unit which was separated slowly from the mother unit. The main design drivers of this experiment were to build such high power equipments in a standard type of sounding rocket, to keep the cost within the budget and to perform a series of experiments without complete loss of the mission. The key technology for this experiment is a rocket-borne magnetron and high voltage converter. Location of position of the daughter unit relative to the mother unit was a difficult requirement for a spin-stabilized rocket. These problems were solved by application of such a low cost commercial products as a magnetron for microwave oven and a video tape recorder and camera.

Rocket observations of electron density in the nighttime E region using Faraday rotation

Abstract: A rocket radio propagation experiment is described in which the electron density profile of the nighttime E region is obtained with an accuracy of 100 per cu cm. The factors limiting the accuracy of the experiment are found to be related to atmospheric and receiver noise and to the use of a magnetometer to determine the spin rate of the rocket. The Fourier analysis used for the frequency measurement may also contribute error under conditions of steep electron density gradients. The accuracy being achieved appears to be adequate for present applications of the experiment.

Dynamics of variable mass systems with application to the star 48 solid rocket motor

Abstract: Existing methods for the derivation of equations of motion of variable mass systems are reviewed and compared, the end product being a system of general dynamical equations for variable mass systems. These equations are used to study the lateral stability problem associated with the Star 48 solid rocket engine. It is shown that the shape of the combustion chamber could have a significant effect on the lateral stability of the rocket; specifically, a short and wide combustion chamber is destabilizing, while a long and narrow chamber is stabilizing.

Injection head for combustion chambers of rocket motors operating on liquid propergol

Abstract: The invention relates to an injection head for combustion chambers of rocket motors operating with liquid ergols, in which one of the ergols participating in the combustion process is introduced into the combustion chamber through several nozzles arranged in the injection head body. According to the invention, the other ergol, in particular a fuel or hydrogen H respectively is introduced into the combustion space 1a through a continuous network of channels 4 which directly surrounds the introduction nozzles 2. The invention applies particularly to the propulsion of missiles.

Gas generator fuel flow throttle control system

Abstract: A gas generator fuel flow throttle control system provides a fuel rich gas to a propellant grain of a small diameter rocket. An adaptive iterative gain technique allows the throttle to closely follow a commanded fuel flow rate as required by a missile processor.

Device for the damping of combustion chamber vibrations in liquid-fuelled rocket engines

Abstract: Device for the damping of gas vibrations occurring during the combustion process inside the combustion chamber of rocket engines, which function with liquid propellants, by means of damping chambers arranged in the area of the injection head, which chambers are connected to the combustion chamber by way of through-passages. Here, the damping chambers are provided inside the injection head, distributed over the entire front face of the latter.

Acceleration of electrons in strong beam‐plasma interactions

Abstract: The effects of strong beam-plasma interactions on the electron population of the upper atmosphere have been investigated in an electron acceleration experiment performed with a sounding rocket. The rocket carried the Several Complex Experiments (SCEX) payload which included an electron accelerator, three disposable 'throwaway' detectors (TADs), and a stepped electron energy analyzer. The payload was launched in an auroral arc over the rocket at altitudes of 157 and 178 km, respectively. The performance characteristics of the instruments are discussed in detail. The data are combined with the results of laboratory measurements and show that electrons with energies of at least two and probably four times the injection energy of 2 keV were observed during strong beam-plasma interaction events. The interaction events occurred at pitch angles of 54 and 126 degrees. On the basis of the data it is proposed that the superenergization of the electrons is correlated with the length of the beam-plasma interaction region.

The electromagnetic rocket gun -- A novel launch concept

Abstract: A novel propulsion concept is proposed which has the potential to accelerate large masses to high velocities. The novel concept is an electromagnetic gun where the projectile is a rocket. As in a rocket, where the propellant cools and thereby prevents the rocket to burn up, the same happens in the proposed concept where the propellant also cools the projectile and prevents its vaporization. The propellant is resistively heated by the magnetic field to high temperatures and ejected from the projectile with high velocity. The total thrust is the sum of the magnetic and recoil force. The energy to drive the jet is externally supplied making the specific impulse much larger than for chemical rockets.

Directional control of rockets using elastic deformation of structural members

Abstract: A missile is disclosed which utilizes elastic deformation of structural members in order to control missile flight. The elastic deformation may be in the mounting of the rocket nozzle, the provision of deformable control surfaces, or provision of deformable sections of rocket body, all of which are controlled by independent actuating means.

Propulsion options for orbit-on-demand vehicles

Abstract: Vehicles which can achieve orbit within minutes of a command decision may be needed in the future for a variety of missions. Such orbit-on-demand vehicles may have propulsion requirements that are somewhat different from vehicles designed for routine transportation, but the propulsion evaluation studies of the past need to be considered as a starting point for orbit-on-demand vehicle studies. This paper surveys airbreathing propulsion studies including composite, airturbo-rocket, and scramjet systems and rocket propulsion studies including composite, airturborocket, and scramjet and rocket propulsion studies including dual-fuel and pure hydrocarbon systems. One indication from the results is that a horizontal takeoff airbreathing system with supersonic staging will have a higher development cost than rocket systems primarily because of the cost of the airbreathing engine development. Another indication is that pure hydrocarbon rocket propulsion for a vertical takeoff system may be feasible. Eliminating the requirement for hydrogen fuel may be worthwhile for orbit-on-demand vehicles.