Rocket

About: Rocket is a research topic. Over the lifetime, 14018 publications have been published within this topic receiving 95852 citations. The topic is also known as: rockets.

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.

Optimal Design of Hybrid Rocket Motors for Microgravity Platform

Abstract: A nested direct/indirect method is used to find the optimal design for a microgravity platform which is based on a hybrid sounding rocket. The direct optimization of the parameters that affect the motor design is coupled with the indirect trajectory optimization to maximize a given mission performance index. A gas-pressure feed system is used, with three different propellant combinations. The feed system exploits a pressurizing gas, namely, helium, when hydrogen peroxide or liquid oxygen is used as an oxidizer. The simplest blowdown design is compared with a more complex pressurizing system, which has an additional gas tank that allows for a phase with constant propellant tank pressure. Only self-pressurization is considered with nitrous oxide; two different models are used to describe the behavior of the tank pressurization. The simplest model assumes liquid/vapor equilibrium. A two-phase model is also proposed: Saturated vapor and superheated liquid are considered and the liquid/vapor mass transfer evaluation is based on the liquid spinodal line. Results show that the different tank-pressurization models yield minimal differences of the optimal motor characteristics. Performance differs slightly due to the different mass of the residual oxidizer. The propellant comparison for the present case shows better performance for hydrogen peroxide/ polyethylene with respect to liquid oxygen/hydroxyl-terminated polybutadiene, while nitrous oxide/hydroxyl-terminated polybutadiene remains attractive for system simplicity and low costs.

In-Flight Alignment and Calibration of Inertial Measurement Units - Part I: General Formulation

Abstract: This is the first part of a two-part paper which summarizes work pursued by the author in 1966 [1]. The paper describes the application of minimum-variance estimation techniques for in-flight alignment and calibration of an inertial measurement unit (IMU) relative to another IMU and/or some other reference. The first part formulates the problem, and the second part [2] reports numerical results and analyses. The approach taken is to cast the problem into the framework of Kalman-Bucy estimation theory, where velocity and position differences between the two IMU's are used as observations and the IMU parameters of interest become part of the state vector. Instrument quantization and computer roundoff errors are considered as measurement noise, and environmental induced random accelerations are considered as state noise. Typical applications of the technique presented might include the alignment and calibration of IMU's on aircraft carriers, the initialization of rockets or rocket airplanes which are launched from the wing of a mother ship, the alignment and calibration of IMU's which are only used in the latter phases of rocket flight, and for the initialization/updating of SST guidance systems.

Progress to Date

Abstract: At this point in its development, the solar sail can be characterized as fairly late in its theoretical phase and fairly early in its developmental phase. It is probably equivalent to the chemical rocket in 1930, the automobile in 1900, and the heavier-than-air aircraft in 1910.