Space engine safety system

A rocket engine safety system was designed to initiate control procedures to minimize damage to the engine or vehicle or test stand in the event of an engine failure. The features and the implementation issues associated with rocket engine safety systems are discussed, as well as the specific concerns of safety systems applied to a space-based engine and long duration space missions. Examples of safety system features and architectures are given, based on recent safety monitoring investigations conducted for the Space Shuttle Main Engine and for future liquid rocket engines. Also, the general design and implementation process for rocket engine safety systems is presented

The application of neural networks to the SSME startup transient

Feedforward neural networks were used to model three parameters during the Space Shuttle Main Engine startup transient. The three parameters were the main combustion chamber pressure, a controlled parameter, the high pressure oxidizer turbine discharge temperature, a redlined parameter, and the high pressure fuel pump discharge pressure, a failure-indicating performance parameter. Network inputs consisted of time windows of data from engine measurements that correlated highly to the modeled parameter. A standard backpropagation algorithm was used to train the feedforward networks on two nominal firings. Each trained network was validated with four additional nominal firings. For all three parameters, the neural networks were able to accurately predict the data in the validation sets as well as the training set

Labor Market Implications of Rising Costs of Employer-Provided Health Insurance

Variation in income tax policies and health insurance costs are shown to be theoretically appropriate instruments to identify endogenous firm wage and benefit offers in a labor supply model. Empirical results show that firms are more likely to provide health insurance benefits in states with high marginal income tax rates and low hospitalization costs. The model implies that over the 1983-1995 period, large increases in health insurance costs and reductions in marginal income tax rates lowered the probability of receiving health insurance benefits from employers by 10 percentage points. This decrease in benefits lowered hours of labor supply by 4-7%.

Spring 1980 Conference Issue

Plastic Water Pipe: How Well Does it Hold Up? (page 3) Forty-Ninth Annual Turf Conference and Fourth Industrial Show Program (10) Blend Bluegrasses for Best Disease Resistance (13) Dollar Spot Fungicide Trials--1979 (16) UMass Turfgrass Research Fund (18

Testing of a Liquid Oxygen/Liquid Methane Reaction Control Thruster in a New Altitude Rocket Engine Test Facility

A relocated rocket engine test facility, the Altitude Combustion Stand (ACS), was activated in 2009 at the NASA Glenn Research Center. This facility has the capability to test with a variety of propellants and up to a thrust level of 2000 lbf (8.9 kN) with precise measurement of propellant conditions, propellant flow rates, thrust and altitude conditions. These measurements enable accurate determination of a thruster and/or nozzle s altitude performance for both technology development and flight qualification purposes. In addition the facility was designed to enable efficient test operations to control costs for technology and advanced development projects. A liquid oxygen-liquid methane technology development test program was conducted in the ACS from the fall of 2009 to the fall of 2010. Three test phases were conducted investigating different operational modes and in addition, the project required the complexity of controlling propellant inlet temperatures over an extremely wide range. Despite the challenges of a unique propellant (liquid methane) and wide operating conditions, the facility performed well and delivered up to 24 hot fire tests in a single test day. The resulting data validated the feasibility of utilizing this propellant combination for future deep space applications

A Deep-to-Shallow Transition in the Fort Payne Formation (Lower Mississippian), Kentucky Highway 61, Cumberland County, Kentucky

The Fort Payne Formation of the Cumberland Saddle region of south-central Kentucky and north-central Tennessee is part of a vast marine sedimentation system that extended over much of North America during the Early Mississippian Period; broadly similar facies reached from Georgia through Tennessee and Kentucky, into western Illinois and Missouri, and into New Mexico and the northern Rockies (Pryor and Sable, 1974). Throughout North America the Fort Payne and its equivalents overlie a black shale (in Kentucky called the Chattanooga Shale) and underlie thick carbonates (in Kentucky, the Warsaw Formation and younger middle Mississippian limestones). Six miles south of Burkesville, Ky., on Kentucky Highway 61, a complete section of the Fort Payne, from the top of the Chattanooga Shale well into the overlying Warsaw Formation, is exposed in 11 outcrops (Figs. 1-3). The Fort Payne is approximately 270 feet thick in this section and is composed of basal wackestone mounds; distinctive, fossiliferous, green clay shales associated with the mounds; detrital crinoidal packstones; argillaceous dolosiltstones, the most common lithology in the Fort Payne; and a dark, organic-rich shale, which caps a persistent coarsening-upward packstone unit