330 Matching Results

Search Results

Advanced search parameters have been applied.

Stability of ballistic reentry bodies

Description: Report discussing various features of the stability of ballistic reentry shapes, including considerations for ballistic-missile and manned-satellite reentry capsules. Attainment of satisfactory stability of reentry bodies with subsonic terminal velocities was not found to be too difficult, but undesirable features that may cause marginal stability characteristics may be introduced in an effort to minimize weight. Reentry bodies with supersonic terminal velocities have fewer stability issues.
Date: August 11, 1958
Creator: Bird, John D. & Reese, David E., Jr.
Partner: UNT Libraries Government Documents Department

Ex-Offender Reentry: An Analysis of Current Policies and Programs

Description: Recidivism rates among ex-offender populations have consistently remained high. With over 600,000 ex-offenders being released from prison each year, reducing the rate of recidivism among the ex-offender class has become a highly debated issue. Ensuring ex-offenders successfully reintegrate into the community post-incarceration may help to reduce recidivism rates. Through a qualitative thematic analysis, this study examined various policies and program that may impact recidivism rates among ex-offenders. The policies and programs reviewed in this study were categorized among six main themes which were identified in prior literature as the most crucial elements needed for successful reintegration. The findings indicate that while many policy changes have been made to positively impact ex-offender reintegration by allowing initial access to services post-release from prison, more should be done to ensure ex-offenders actually receive needed services.
Date: December 2017
Creator: Laird, Kaleigh B.
Partner: UNT Libraries

Preliminary Aerodynamic Data Pertinent to Manned Satellite Reentry Configurations

Description: Report presenting some experimental data and calculations for a variety of aerodynamic shapes considered for use as manned reentry vehicles. Three types of vehicles were tested: non-lifting bodies, lifting bodies, and airplane-like vehicles. All of the configuration types were found to be suitable for use as manned reentry vehicles with certain fin and flap modifications for certain shapes.
Date: July 21, 1958
Creator: Penland, Jim A. & Armstrong, William O.
Partner: UNT Libraries Government Documents Department

An Estimate of the Fluctuating Surface Pressures Encountered in the Reentry of a Ballistic Missile

Description: Note presenting calculations made of the magnitude of the surface sound pressure levels that will occur on blunt-nosed vehicles during reentry into the earth's atmosphere. The results presented cover a wide range of re-entrance velocities and reentrance angles into the atmosphere and sizes and weights of the vehicle.
Date: July 1958
Creator: Callaghan, Edmund E.
Partner: UNT Libraries Government Documents Department

Control of a high beta maneuvering reentry vehicle using dynamic inversion.

Description: The design of flight control systems for high performance maneuvering reentry vehicles presents a significant challenge to the control systems designer. These vehicles typically have a much higher ballistic coefficient than crewed vehicles like as the Space Shuttle or proposed crew return vehicles such as the X-38. Moreover, the missions of high performance vehicles usually require a steeper reentry flight path angle, followed by a pull-out into level flight. These vehicles then must transit the entire atmosphere and robustly perform the maneuvers required for the mission. The vehicles must also be flown with small static margins in order to perform the required maneuvers, which can result in highly nonlinear aerodynamic characteristics that frequently transition from being aerodynamically stable to unstable as angle of attack increases. The control system design technique of dynamic inversion has been applied successfully to both high performance aircraft and low beta reentry vehicles. The objective of this study was to explore the application of this technique to high performance maneuvering reentry vehicles, including the basic derivation of the dynamic inversion technique, followed by the extension of that technique to the use of tabular trim aerodynamic models in the controller. The dynamic inversion equations are developed for high performance vehicles and augmented to allow the selection of a desired response for the control system. A six degree of freedom simulation is used to evaluate the performance of the dynamic inversion approach, and results for both nominal and off nominal aerodynamic characteristics are presented.
Date: May 1, 2005
Creator: Watts, Alfred Chapman
Partner: UNT Libraries Government Documents Department

High-G testing of MEMS mechanical non-volatile memory and silicon re-entry switch.

Description: Two different Sandia MEMS devices have been tested in a high-g environment to determine their performance and survivability. The first test was performed using a drop-table to produce a peak acceleration load of 1792 g's over a period of 1.5 ms. For the second test the MEMS devices were assembled in a gun-fired penetrator and shot into a cement target at the Army Waterways Experiment Station in Vicksburg Mississippi. This test resulted in a peak acceleration of 7191 g's for a duration of 5.5 ms. The MEMS devices were instrumented using the MEMS Diagnostic Extraction System (MDES), which is capable of driving the devices and recording the device output data during the high-g event, providing in-flight data to assess the device performance. A total of six devices were monitored during the experiments, four mechanical non-volatile memory devices (MNVM) and two Silicon Reentry Switches (SiRES). All six devices functioned properly before, during, and after each high-g test without a single failure. This is the first known test under flight conditions of an active, powered MEMS device at Sandia.
Date: October 1, 2005
Creator: Baker, Michael Sean & Pohl, Kenneth Roy
Partner: UNT Libraries Government Documents Department

Massively parallel computational fluid dynamics calculations for aerodynamics and aerothermodynamics applications

Description: Massively parallel computers have enabled the analyst to solve complicated flow fields (turbulent, chemically reacting) that were previously intractable. Calculations are presented using a massively parallel CFD code called SACCARA (Sandia Advanced Code for Compressible Aerothermodynamics Research and Analysis) currently under development at Sandia National Laboratories as part of the Department of Energy (DOE) Accelerated Strategic Computing Initiative (ASCI). Computations were made on a generic reentry vehicle in a hypersonic flowfield utilizing three different distributed parallel computers to assess the parallel efficiency of the code with increasing numbers of processors. The parallel efficiencies for the SACCARA code will be presented for cases using 1, 150, 100 and 500 processors. Computations were also made on a subsonic/transonic vehicle using both 236 and 521 processors on a grid containing approximately 14.7 million grid points. Ongoing and future plans to implement a parallel overset grid capability and couple SACCARA with other mechanics codes in a massively parallel environment are discussed.
Date: September 1, 1998
Creator: Payne, J.L. & Hassan, B.
Partner: UNT Libraries Government Documents Department

Investigation and Evaluation of Geopressured-Geothermal Wells; Detailed Reentry Prognosis for Geopressure-Geothermal Testing of Dr. M.O. Miller No. 1 Well

Description: This Gruy Federal Type I-A prospect was drilled as the Union Oil Company of California, Dr. M.O. Miller No. 1 and is located in Section 34, T15S, R5W, Cameron Parish, Louisiana. The land belongs to the heirs of Dr. Miller and is unleased. The well site is approximately 350 feet southwest of the northwest corner of Section 34 and approximately 4,000 feet south-southeast of Prospect L-3, Buttes Gas and Oil Co. et al., Gladys McCall No. 1. The former well site is accessible by approximately 2.8 miles of canal levee on which a board road would have to be constructed. In addition, there are two wooden bridges in fair condition to be crossed which will require minor repairs. The well was drilled to a total depth of 18,158 feet and plugged and abandoned as a dry hole mid 1965.
Date: April 21, 1978
Partner: UNT Libraries Government Documents Department

RTG Impact Response to Hard Landing During Mars Environmental Survey (MESUR) Mission

Description: This paper presents the results done to perform specialized RTG design studies. The analytical results indicate that a lander by itself experiences much higher g-loads than the lander with an integral penetrator; but that minor modifications of the shape of the lander can very substantially reduce the maximum g-load during landing, thus eliminating the need for retrorockets for RTG survival. Paper presented at the 27th IECEC in San Diego, CA August 3-7, 1992. Also included are four copies (3 bound) from Fairchild presentation.
Date: August 1, 1992
Creator: Schock, Alfred & Mukunda, Meera
Partner: UNT Libraries Government Documents Department

Development of a parachute recovery system for a reentry nose cone (NRV)

Description: A two-stage parachute system consisting of a 19-in. dia ribbon parachute and a 3-ft dia guide surface parachute which is deployed 1.9 s after initial deployment is described. A 1.25 ft/sup 3/ ram air-filled flotation bag with radio beacon is used for ocean recovery of the 40-lb nose cone. Recovery was initiated by jettisoning 60 percent of the initial reentry mass prior to parachute deployment.
Date: September 1, 1977
Creator: Pepper, W.B.
Partner: UNT Libraries Government Documents Department

Mars Pathfinder airbag impact attenuation system

Description: The Mars Pathfinder spacecraft, scheduled for launch in November 1996, is designed to validate a low cost Entry, Descent, and Landing system and to perform scientific surface operations. The Jet Propulsion Laboratory and Sandia National Laboratories teamed to design, fabricate, test and validate a prototype 0.38 scale model of an airbag impact attenuation system. A computer code was developed to predict the performance of the airbag system. A test program in Sandia`s High Altitude Chamber was performed to validate the code and demonstrate the feasibility of the airbag concept and design. In addition, freefall tests were performed at representative velocities to demonstrate the structural integrity of the airbag system design. The feasibility program demonstrated that the airbag impact attenuation design will protect the lander upon impact with the Martian surface.
Date: April 1, 1995
Creator: Waye, D.E.; Cole, J.K. & Rivellini, T.P.
Partner: UNT Libraries Government Documents Department

BALTRIM v.1

Description: BalTrim is an Excel(R) spreadsheet designed to calculate the inertial mass properties and ballast trim weight for either an assembled reentry vehicle (RV) or reentry body (RB). With this application, the user enters known mass properties and global coordinates for each subcomponent of the assembly, and BalTrim calculates the mass properties of the total assembly. Then, using the assembly mass properties, BalTrim calculates the necessary amount of ballast trim weight required to dynamically and statically balance the assembly mass properties. The final mass properties and trim ballast weight calculated with BalTrim agree with physicaly measured values.
Date: February 1, 1999
Creator: Gaffney, Thomas M.
Partner: UNT Libraries Government Documents Department

Results of W-87/Mk21 Deployment Separation Shock Tests

Description: This report summarizes results of the W-87/Mk21 Deployment Separation Shock Tests conducted at the Survivability and Vulnerability Integration Center (SVIC) Hill Air Force Base in Ogden, Utah, from 10/5/98 to 10/8/98. Specific details regarding the test plan and procedures can be found in the Master Test Plan listed in the references. Test Objectives: (1) Evaluate the performance of a set of servo accelerometers during and post Re-entry Vehicle (RV) separation events. These ultra-sensitive accelerometers ({mu}g) needed operate during and after the separation shock events and these tests would serve as confirmation of proper functioning. These sensors were later flown on FrU-15, a development flight unit supporting the Instrumented High Fidelity Joint Test Assembly Program, as part of an experimental Inertial Measurement Unit (IMU) measure RV dynamics during RV mechanical separation and spin-up. (2) Measure separation shock response at the IMU accelerometer locations. (3) Measure separation shock response at locations on the warhead and RV common to locations used on MMIII separation tests conducted at LMMS Valley Forge for data comparison.
Date: April 21, 1999
Creator: Avalle, C. A.
Partner: UNT Libraries Government Documents Department

Measurement of lateral launch loads on re-entry vehicles using SWAT

Description: The Sum of Weighted Accelerations Technique (SWAT) has been developed at Sandia National Laboratories to infer dynamic forces acting on free elastic structures from acceleration measurements. A derivative of SWAT known as SWAT TEEM (Sum of Weighted Accelerations using Tome Eliminated Elastic Modes) is utilized. This paper describes experiments demonstrating how this technology can be applied to measure lateral launch loads on Re-entry Vehicle (RV) payloads. A technique to determine the number of sensors and best locations is described. Experiments are performed to excite a structure to which a mockup RV is mounted. Acceleration measurements on the RV are used to reconstruct the lateral force acting at the RV base, and these results are compared to measured results.
Date: November 1, 1993
Creator: Mayes, R. L.
Partner: UNT Libraries Government Documents Department

The Apollo 17 Lunar Surface Journal

Description: The material included in the Apollo 17 Lunar Surface Journal has been assembled so that an uninitiated reader can understand, in some detail, what happened during Apollo 17 and why and what was learned, particularly about living and working on the Moon. At its heart, the Journal consists a corrected mission transcript which is interwoven with commentary by the crew and by Journal Editor -- commentary which, we hope, will make the rich detail of Apollo 17 accessible to a wide audience. To make the Journal even more accessible, this CD-ROM publication contains virtually all of the Apollo 17 audio, a significant fraction of the photographs and a selection of drawings, maps, video clips, and background documents.
Date: August 1995
Creator: Jones, E. M.
Partner: UNT Libraries Government Documents Department

The Story of Pathfinders [Family Pathfinders]: Investigating the Impact, Experiences, and Context of Re-Entry Mentoring

Description: The United States has the largest population of imprisoned persons in the world. The vast majority of these individuals eventually leave prison and re-enter society, facing a number of challenges in the process. Those who are unable to successfully re-enter society run the risk of recidivating back into the prison system. Mentoring has the potential to promote successful re-entry and help offenders to get their lives back on track. Pathfinders of Tarrant County is a unique organization. Its historical position as one of the foremost "welfare to work" programs gives it unique insight into the economic struggles of at-risk individuals and families, and its existing relationships with mentors and other community organizations gives it a rich pool of resources to draw from. By helping to connect participants with community resources, Pathfinders removes quite a bit of the complexity from seeking help at a time when vulnerable people need it most. This thesis presents an overview of how Pathfinders conducts mentoring and its unique brand of social service advocacy, including the unique and not-so unique challenges that a re-entry population may have to offer.
Date: December 2016
Creator: Hanich, Kristen Marie
Partner: UNT Libraries

Investigation and Evaluation of Geopressured-Geothermal Wells; Detailed Reentry Prognosis for Geopressure-Geothermal Testing of State Lease 4183 No. 1 Well

Description: This Gruy Federal Type III-A geopressured-geothermal (Geo) prospect was drilled as the Pan American Petroleum Corporation (now Amoco) No. 1 State Lease No. 4183, serial No. 1702399670. The well was abandoned in February 1970. it is located 1,200 feet north and 2,300 feet east from the southwest corner of Section 27, Township 15S, Range 4W. The location is shown on the USGS topographic sheet ''Hog Bayou'', a portion of which is included as figure I. The well is accessible by lease roads off State Highway No. 82. A location plat is included as figure II. This Geo prospect is located on State land within the Rockefeller Wildlife Refuge and Game Preserve. The oil and gas leasehold rights are held by production from another well owned and operated by Amoco Production Company and other joint partners.
Date: June 16, 1978
Partner: UNT Libraries Government Documents Department

Investigation and Evaluation of Geopressured-Geothermal Wells; Detailed Reentry Prognosis for Geopressure-Geothermal Testing of The Watkins-Miller No. 1 Well, Cameron Parish, Louisiana

Description: This Gruy Federal Type II-B prospect was drilled as the Superior Oil Company No. 1 Watkins-Miller, API designation 17-023-20501 and is located in Section 5, T15S, R5W, Cameron Parish, Louisiana. The well site is just north of lot 39 on Indian Point Island and is readily accessible from state highway Route 82 and a shell road in good condition. Superior Oil completed this well in late 1970 as a dual gas producer in sands between 11,150 and 11,250 feet but eventually abandoned the well in December, 1974. The cellar of the well is still visible on the site. This location is shown on the lower portion of USGS topographic sheet ''Grand Lake West'' in the map pocket of the Gruy Federal report ''Investigation and Evaluation of Geopressured-Geothermal Wells, Prospective Test Wells in the Texas and Louisiana Gulf Coast'', February 28, 1978.
Date: April 13, 1978
Partner: UNT Libraries Government Documents Department