Aerospace Engineering Commons^™

A Ka-Band High Data Rate Shipboard Satellite Terminal, M. Rupar, David Beering, D. Hoder

Online Journal of Space Communication

A fully articulated steerable shipboard satellite antenna system operating at Ka-band was developed by engineers from the Naval Research Laboratory (NRL), NASA's Glenn Research Center, and a number of industry partners. A series of tests conducted in October of 1998 on Lake Michigan achieved an unparalleled data rate transmission of 45 megabits per second (Mbps) between a moving vessel at sea and a fixed-earth station using NASA's Advanced Communications Technology Satellite (ACTS). Network and application layer tests ran concurrently with the data rate transmission trials, examining TCP/IP file transfers, video and voice transfer technologies, and Asynchronous Transfer Mode (ATM) techniques. …

Gigabit Satellite Network For Nasa's Advanced Communication Technology Satellite (Acts): Features, Capabilities, And Operations, M. Bergamo, D. Hoder

Online Journal of Space Communication

This paper describes the Gigabit Satellite Network (GSN) being developed under joint sponsorship of NASA and ARPA. The system will use the wide-band Satellite Switched Time Division Multiple Access (SS-TDMA) capability and hopping beam antennas of NASA's Advanced Communications Technology Satellite (ACTS). The GSN network will provide full-duplex SONET services over satellite at OC-3 (155.54 Mb/s) and OC-12 (622.078 Mb/s) rates. Typical applications will include connection of distributed SONET/ATM fiber "islands" over satellite, wide-area distributed supercomputer networking, high-definition digital TV, and high-speed file transfer.

The RF link consists of 30 GHz uplink and 20 GHz downlink signals transmitted using a …

Acts 118x Final Report High-Speed Tcp Interoperability Testing, W. Ivancic, M. Zernic, D. Hoder, D. Brooks, David Beering, A. Welch

Online Journal of Space Communication

With the recent explosion of the Internet and the enormous business opportunities available to communication system providers, great interest has developed in improving the efficiency of data transfer using the Transmission Control Protocol (TCP) of the Internet Protocol (IP) suite. The satellite system providers are interested in solving TCP efficiency problems associated with long delas and error-prone links. Similarly, the terrestrial community is interested in solving TCP problems over high-bandwidth links. Whereas the wireless community is intested in improving TCP performance over bandwidth constrained, error-prone links.

NASA realized that solutions had already been proposed for most of the problems associated …

A History Of The Improvement Of Internet Protocols Over Satellites Using Acts, M. Allman, S. Ostermann, H. Kruse

Online Journal of Space Communication

This paper outlines the main results of a number of ACTS experiments on the efficacy of using standard Internet protocols over long-delay satellite channels. These experiments have been jointly conducted by NASA's Glenn Research Center and Ohio University over the last six years.

The focus of our investigations has been the impact of long-delay networks with non-zero bit-error rates on the performance of the suite of Internet protocols. In particular, we have focused on the most widely used transport protocol, the Transmission Control Protocol (TCP), as well as several application layer protocols. This paper presents our main results, as well …

Nasa Acts Satellite: A Disaster Recovery Test, H. Kruse, D. Flournoy

Online Journal of Space Communication

In September 1993, NASA launched its long-awaited Advanced Communication Technology (ACTS) satellite. ACTS is a $500 million experimental all-digital spacecraft hosting a number of first-time technologies: on-board processing and switching, high-powered electronically hopping spot beams, adaptive rain-fade compensation and opening of the Ka frequency band.

Among the earliest of the tests on the new satellite was a NASA sponsored project conducted by Ohio University and its commercial partner, the Huntington National Bank. HNB is a $17 billion regional bank with 338 offices in fourteen states. Transactions on HNB's data networks currently travel on terrestrial T-1 lines. The Ohio University/HNB tests …

Survey Of Advanced Applications Over Acts, Robert Bauer, Paul Mcmasters

Online Journal of Space Communication

The Advanced Communications Technology Satellite (ACTS) system provided a national testbed that enabled advanced applications to be tested and demonstrated over a live satellite link. Of the applications that used ACTS, some offered unique advantages over current methods, while others simply could not be accommodated by conventional systems. The initial technical and experiments results of the program were reported at the 1995 ACTS Results Conference, in Cleveland, Ohio. Since then, the Experiments Program has involved 45 new experiments comprising 30 application experiments and 15 technology related experiments that took advantage of the advanced technologies and unique capabilities offered by ACTS. …

Propagation Effects Handbook For Satellite Systems Design, Louis J. Ippolito

Online Journal of Space Communication

This paper describes the latest edition of the NASA Propagation Effects Handbook for Satellite Systems Design and presents a summary of application of the handbook information to satellite link design and performance. NASA, which has supported a large part of the experimental work in radiowave propagation on space communications links, recognized the need for a reference handbook of this type, and initiated a program in the late 1970's to develop and update a document that will meet this need. The Fifth Edition provides, in a single document, an update to two previous NASA handbooks; the fourth edition of a handbook …

Special Effects: Antenna Wetting, Short Distance Diversity And Depolarization, Roberto J. Acosta

Online Journal of Space Communication

The Advanced Communication Technology Satellite (ACTS) communications system operates in the Ka frequency band. ACTS uses multiple, hopping, narrow beams and very small aperture terminal (VSAT) technology to establish a system availability of 99.5% for bit-error-rates of 5x 10-7 or better over the continental United States. In order maintain this minimum system availability in all US rain zones, ACTS uses an adaptive rain fade compensation protocol to reduce the impact of signal attenuation resulting from propagation effects. The purpose of this paper is to present the results of system and sub-system characterizations considering the statistical effects of system variances due …

Ka-Band System And Propagation Effects On System Performance, Roberto J. Acosta, Sandra Johnson

Online Journal of Space Communication

The Advanced Communication Technology Satellite (ACTS) is an experimental communications satellite system launched in September 1993. ACTS introduces many new technologies, including operation in the Ka frequency band. ACTS uses multiple hopping narrow beams and very small aperture terminal (VSAT) technology to establish a system availability of 99.5% for a bit-error-rates of 5x10-7 or better over the continental United States. In order to maintain a minimum system availability f 99.5% over all US rain zones ACTS uses an adaptive rain fade compensation protocol to reduce the impact of signal attenuation resulting from propagation effects. The purpose of this paper is …

Comparison Of Multiple Rain Attenuation Models With Three Years Of Ka Band Propagation Data Concurrently Taken At Eight Different Locations, Glenn S. Feldhake, Lynn Ailes-Sengers

Online Journal of Space Communication

In June 1996, Working Party 3M of the ITU-R presented research comparing the estimations of 10 rain attenuation models with the 186 station years of earth-space propagation data contained within the ITU-R database known as DBSG5. Now, twenty-one station years of new data taken exclusively in the Ka band (20.185 GHz and 27.505 GHz) across North America are measured against many of those same models. Results are presented both in terms of error statistics as well as in comparison to the ITU database results.

Rain Attenuation Model Comparison And Validation, Charles E. Mayer, Bradley E. Jaeger

Online Journal of Space Communication

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Ka-Band Propagation Modeling For Fixed Satellite Applications, Asoka Dissanayake

Online Journal of Space Communication

Propagation impairments produced by the troposphere are a limiting factor for the effective use of the 20/30 GHz frequency band. Use of smaller earth terminals, while very attractive for consumer and transportable applications, make it difficult to provide sufficient link margin for propagation related outages. In this context, reliable prediction of propagation impairments for low-availability systems becomes important. This paper addresses the issues related to predicting different types of propagation impairments as well as combining them together to determine the overall impact on satellite links over a wide range of outage probabilities.

A Prediction Model That Combines Rain Attenuation And Other Propagation Impairments Along Earth-Satellite Paths, Asoka Dissanayake, Jeremy Allnutt, Fatim Haidara

Online Journal of Space Communication

The rapid growth of satellite services using higher frequency bands such as the Ka-band has highlighted a need for estimating the combined effect of different propagation impairments. Many projected Ka-band services will use very small terminals and, for some, rain effects may only form a relatively small part of the total propagation link margin. It is therefore necessary to identify and predict the overall impact of every significant attenuating effect along any given path.

A procedure for predicting the combined effect of rain attenuation and several other propagation impairments along earth-satellite paths is presented. Where accurate models exist for some …

Acts Propagation Experiment: Experiment Design, Calibration, And Data Preparation And Archival, Robert K. Crane, Xuhe Wang, D. B. Westenhaver, Wolfhard J. Vogel

Online Journal of Space Communication

The National Aeronautics and Space Administration Advanced Communications Technology Satellite (ACTS) propagation experiment was designed to obtain slant-path attenuation statistics for locations within the United States and Canada for use in the design of low-margin Ka-band satellite communication systems. Experimenters at seven different locations have collected propagation data for more than two years. The propagation terminals used for the experiment were identical. A single preprocessing program was used by the experimenters to provide for automatic calibration, generation of attenuation histograms, and data archival. In this paper, the calibration procedures are described and estimates given for measurement accuracy.

ACTS provided beacons …

Ka-Band Propagation Measurements: An Opportunity With The Advanced Communications Technology Satellite (Acts), Robert Bauer

Online Journal of Space Communication

The Advanced Communications Technology Satellite (ACTS) was conceived at the National Aeronautics and Space Administration (NASA) as a follow-on program to its long history in satellite communications projects that have reduced the risk of developing new technologies that fall outside the sponsorship capability of the private sector.

To counter the foreign challenge that developed in the late 1970's to the once insuperable U.S. lead in this field, ACTS was developed to maintain the U.S. preeminence. Launched in September 1993 from the space shuttle, key technologies on ACTS include a multibeam antenna, a baseband processor, a 900-MHz wideband microwave switch matrix, …

Advanced Communications Technology Satellite (Acts): Design And On-Orbit Performance Measurements, Frank Gargione, R. Acosta, T. Coney, R. Krawczyk

Online Journal of Space Communication

The Advanced Communications Technology Satellite (ACTS), developed and built by Lockheed Martin Astro Space for the NASA Lewis Research Center, was launched in September 1993 on the Shuttle STS 51 mission. ACTS is a digital experimental communications test bed that incorporates gigahertz bandwidth transponders operating at Ka band, hopping spot beams, on-board storage and switching, and dynamic rain fade compensation. This paper describes the ACTS enabling technologies, the design of the communications payload, the constraints imposed on the spacecraft bus, and the measurements conducted to verify the performance of the system in orbit.

Historical Development: Acts Technology, Richard Gedney, Ron Schertler, Frank Gargione

Online Journal of Space Communication

The following material has been extracted from "The Advanced Communications Technology Satellite" book by Richard Gedney, Ron Schertler and Frank Gargione.

Issue 2: From The Guest Editor, Frank Gargione

Online Journal of Space Communication

Guest editor introduction

Historical Development: Acts Program Formulation, Richard Gedney, Ron Schertler, Frank Gargione

Online Journal of Space Communication

The following material has been extracted from "The Advanced Communications Technology Satellite" book by Richard Gedney, Ron Schertler and Frank Gargione.

Perfromance Improvement Of High Bypass Turbofan Engine Through Optimization Of High-Pressure Compressor Blade – A Case Study, Vlad Mandzyuk

Symposium of Student Scholars

This research determines the relation between the High-Pressure Compressor (HPC) blade characteristics, compressor pressure ratio, and lift-to-drag ratio of a high bypass turbofan engine. Alterations in the HPC blades airfoil, span, chord, taper ratio, twist, aspect ratio, sweep, and angle of incidence are performed and their effect on the engine’s performance is observed. The metrics used to compare engine performance include thrust, specific thrust, exit velocity, fuel/air ratio, power, and efficiency. Parametric cycle analysis and computational fluid dynamics are performed to compare and validate findings. The goal of this study is to optimize the design of HPC to maximize the …

Numerical Simulation Of Flow Past An Airfoil With Ice Accretion On Leading Edge, Boyu Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

The focus of this research is on aerodynamic simulation of flow past NACA 23012 airfoil with clean surface and with ice accretion on its leading edge by using the commercial CFD solver ANSYS Fluent. Reynolds-Averaged Navier-Stokes (RANS) computations are performed using Spalart-Allmaras (SA) and Wray-Agarwal (WA) turbulence models. ANSYS mesh package ICEM is used to model the geometry and generate the mesh. The computations are performed at 0, 2, 4, 6, 8, 10, and 12 degrees angle of attack which are compared with experimental data. For the case of ice accretion at the leading edge, the physical geometry becomes more …

Thermochemistry Of Combustion In Polyvinyl Alcohol + Hydroxylammonium Nitrate, James K. Baird, Robert A. Frederick Jr.

PRC-Affiliated Research

A mixture of polyvinyl alcohol (PVA) and hydroxylammoniun nitrate (HAN) forms a gummy solid known as a plastisol, which is ionically conducting. When an electrostatic potential of 200 V DC is applied across the plastisol, it ignites. Combustion ceases upon removal of the applied voltage. The products of PVA + HAN combustion are known to include the molecular gases carbon monoxide, carbon dioxide, water, nitrogen, and hydrogen. When the electric field within the plastisol is spatially uniform, combustion occurs preferentially at the anode. The fact that HAN is an ionic conductor suggests that the mechanism of combustion is electrolytic in …

Thermochemistry Of Combustion In Polyvinyl Alcohol + Hydroxylammonium Nitrate, James K. Baird, Robert A. Frederick Jr.

PRC-Affiliated Research

A mixture of polyvinyl alcohol (PVA) and hydroxylammoniun nitrate (HAN) forms a gummy solid known as a plastisol, which is ionically conducting. When an electrostatic potential of 200 V DC is applied across the plastisol, it ignites. Combustion ceases upon removal of the applied voltage. The products of PVA + HAN combustion are known to include the molecular gases carbon monoxide, carbon dioxide, water, nitrogen, and hydrogen. When the electric field within the plastisol is spatially uniform, combustion occurs preferentially at the anode. The fact that HAN is an ionic conductor suggests that the mechanism of combustion is electrolytic in …

Autonomous Optimal Trajectory Planning For Orbital Rendezvous, Satellite Inspection, And Final Approach Based On Convex Optimization, Nicholas Ortolano, David K. Geller, Aaron Avery

Space Dynamics Laboratory Publications

Convex optimization techniques have deterministic convergence properties, are self-starting, i.e., they do not require an initial guess, and have been tested in real-time environments. These optimization techniques are applied to the trajectory planning problem for orbital rendezvous and proximity operations. Spacecraft rendezvous, inspection, and final approach trajectories are considered. Optional trajectory constraints are considered, including approach corridors, keep-out zones, and maximum thrust acceleration levels. Two linear dynamics models are investigated: Clohessy-Wiltshire dynamics to describe the relative motion in a local-horizontal local-vertical frame, and a new relative orbital motion dynamics model to describe the motion relative to a spinning or uncontrolled …

Rehology And Electrical Conductivity Of Particulate Composites In Additive Manufacturing, Bin Xia

Mechanical Engineering Research Theses and Dissertations

Extrusion-based multi-functional additive manufacturing (AM) has been a rapidly developing area in AM recently. Particulate composites are widely used in this area to provide different functionalities with different types of particulate additives. However, there is no systematic understanding of the behavior of particulate composites during extrusion (especially in small nozzles) or of their properties once deposited in the build. This work investigates the properties of the type of particulate composites usually used in additive manufacturing, composed of a polymer matrix material and particulate additives within the micrometer scale. The focus is on the material rheology in the nozzle/capillary (for the …

Flying Wing Uav For Surveillance And Object Tracking, Kristen Padgett, Scott Semmelink, Jared Lasley, Paul Horne

Senior Design Project For Engineers

Unmanned aerial vehicles (UAV) have become ubiquitous in recent years due to their adaptability and ease of use. Surveillance UAVs in particular have seen increased interest and usage by law enforcement, civilian security, surveying, and federal services. The increased interest has led to the development of UAVs with increased endurance and payload capacity. Further as many of the applications of surveillance drones involve heightened security requirements, an aircraft of domestic make is preferential to many organizations. With this demand in mind, Inspired Products, LLC put forth a request for assistance in the design and testing of a surveillance UAV. More …

Effect Of Galvanic Corrosion On Crack Propagation Of Cold Expanded Holes In Aa2024-T3, Ken Shishino

Doctoral Dissertations and Master's Theses

A search for the balance between weight reduction and durability of a structure has always been a popular topic within the aerospace industry. Among numerous researches to improve a structure’s fatigue life, processes on mechanically fastened joints have been a topic of focus as it is naturally a discontinuity in the material leading to a local stress concentration under loading. Cold expansion is a well-known technique with a wide range of applications in both new and repaired structures. The benefits include the extension of fatigue life and a delay in crack growth without addition of weight. However, localized galvanic corrosion …

Rocket Flight Simulation With Monte Carlo Uncertainty Analysis, Jonathan Wallace Drake

Honors Capstone Projects and Theses

No abstract provided.

Cybersecurity Considerations With The Increasing Uses Of Small Unmanned Aircraft Systems (Suas) Or Drones, Matthew Kucharek, Stanley Mierzwa

Center for Cybersecurity

The effort to produce this information resource results from a collaborative effort between the Bergen County Technical Schools (high school), through the advisor Andrea Buccino, and a cybersecurity expert mentor. High school senior members of this learning partnership are provided with an interactive learning experience. They gain an increase and knowledge in a particular area of study while under the topical guidance of a mentor. In this example, the high school senior is pursuing coursework in Aerospace Engineering, and this was combined with the focus of cybersecurity to expand the students’ cross-discipline knowledge. This collaborative work was done virtually, given …

Real-Time Material State Assessment Of Composites Using Artificial Intelligence And Its Challenges, Muthu Ram Prabhu Elenchezhian

Mechanical and Aerospace Engineering Dissertations - Archive

Over several decades of careful experimental investigation and exhaustive development of discrete damage analysis methods including integrated computational mechanics methods, our community knows a great deal about how discrete defects such as matrix cracks and defect growth (e.g. delamination) can be predicted in structural composites. For many practical situations controlled by laminated multiaxial composite structures, the loss of performance and “sudden death” end of life is controlled by defect coupling which becomes a precursor to fracture plane development. These interaction sequences are highly dependent on local details of manufacture, design configurations, and loading for a given application material and influenced …