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The Universities of Texas, Minnesota, and New Orleans, and Texas Tech University are undertaking research supported by the Air Force Office of Scientific Research on critical issues for a launch to space from a railgun carried on an airborne platform. The University of Texas at Austin is studying techniques to achieve hypervelocity with a goal of 7 km/s: So far, 5.2 km/s has been achieved in a 7-m augmented railgun using a preinjected plasma armature. Texas Tech University is studying distributed power feed concepts that will improve the efficiency of launch for a long railgun: So far, 11 km/s has been achieved with a plasma arc in a five-stage system. The Universities of Minnesota and New Orleans are investigating the aerothermal behavior of a 10-kg projectile for flight from a high-altitude launch into orbit: So far, the results show that an acceptable amount (∼15 mm) of nosetip ablation will occur. This paper provides an overview of progress in these areas; more details on specific topics are provided in companion papers. [ABSTRACT FROM AUTHOR]

Under a Navy SBIR, Diversified Technologies, Inc. (DTI) will design and demonstrate scalable solid state switches in support of future U.S. Navy needs related to power supplies and inverters. One switch approach being developed consists of a massive series-parallel array of high-voltage insulated gate bipolar transistors that are switched synchronously in order to achieve high peak currents. DTI is evolving its technology in high-voltage switching to include very high peak currents. As an objective of the SBIR effort, DTI will utilize these high-power switches to build a power converter. From a practical viewpoint, high-voltage switches that can operate reliably at large currents have potential applications in missile launchers, high-power actuators, and radar power supplies. The massive series-parallel switch array approach has the potential to provide a compact, reliable, and effective switching solution to converting sufficient electrical energy to kinetic energy that could meet a variety of Navy applications. In this paper, DTI reviews current switch requirements and recent SBIR progress toward the goal of demonstrating massive series-parallel high-voltage switching that meets the Navy SBIR requirements. [ABSTRACT FROM AUTHOR]

Electromagnetic (EM) launch science and technology in the United States continues to advance at a significant pace. The computational and experimental tools for understanding the critical physics issues are sufficiently mature that they are being utilized to provide insight and resolution of the remaining major technical challenges. For example, the primary computational electrodynamics code, EMAP3D, is now implemented in a hybrid finite element-boundary element configuration with moving conductors, providing faster computation and increased understanding of these complex systems. An increased focus on railgun tribology and experiments to understand the interface between railgun armatures and the rail surface is providing important insight for improved railgun lifetimes. Control algorithms for counter-rotating pulsed alternators have been developed and validated experimentally with physical scale simulators. Solid-state switches are replacing the more traditional vacuum switches for high-current and high-voltage railgun power sources. Silicon is the material of choice, but silicon carbide shows great promise for reduced size and increased electrical performance. As a consequence of these and other advances, the U.S. Army has initiated an effort to build a power source with a matched pair of counter-rotating pulsed alternators and a cantilevered railgun to accelerate projectiles to 2-MJ kinetic energy. The U.S. Navy has initiated a new effort to launch large projectiles to hypervelocity. Because of the large naval platform, the size and weight of the power source are not significant issues for the U.S. Navy, whose primary interest is in providing precision fire support to ranges in excess of 200 nmi (500 km). The critical technical issues in implementing this application for the Navy are railgun bore lifetime and high-acceleration-tolerant guidance and control. This paper highlights the recent major achievements in hypervelocity physics, pulsed power, and railgun lifetimes that provide the critical science and technology underpinnings for the Army and Navy EM gun programs. [ABSTRACT FROM AUTHOR]

Discusses the problems experienced in estimating the actual current distribution among various silicon controlled rectifier switches in a converter at the University of Texas at Austin Center for Electromechanics. Importance of multiple switching devices in power converters; Results of the electromagnetic finite-element analysis of one leg of the converter; Role of differential reactance in determining the magnitude of the overload.

Presents an experiment concerning magnetic obturators, an armature concept developed by IAP Research in Dayton, Ohio in the late 1980s. Features of the obturator; Limitations of the obturator; Analysis of starting an obturator without developing arcing contact.

Focuses on a study that presented comparisons between high and low density cases for a number of ballistic parameters. Overview of the approach used to increase kinetic energy in the electrothermal-chemical guns in the United States; Description of gun system; Sensitivity to parameter changes; Conclusions.

The article elaborates on the importance of the 2008 Peter Kemmey Memorial Student Scholarship in the U.S. It is an endowment that recognizes outstanding students in electromagnetic technology that was established as a tribute to the memory of the late Dr. Peter J. Kemmey, who pioneered in the vision to the broad electromagnetic launch initiative. Also featured are the recipients of the scholarship.

The article offers information about the Peter Kemmey Memorial Student Scholarship, which honors outstanding students in electromagnetic technology in the U.S. The scholarship award was established as a tribute to the memory of Peter J. Kemmey, a founding member of the EML Symposium's Permanent Steering Committee. The recipients of the scholarships for 2006 are Anthony J. Johnson of Cornell University and Alex Sitzman of the University of Texas in Austin.

The article presents information on the 12th International Electromagnetic Launch Technology Symposium held in Snowbird, Utah, from May 25 to 28, 2004. This biennial Symposium is the primary forum for presentation and discussion of research on critical technologies for the acceleration of macroscopic objects using electromagnetic or electrothermochemical launchers. The 12th Symposium featured keynote speakers from the leadership of the U.S. Army, U.S. Navy, U.S. Congress and the German Office of Defense Technology and Procurement. In addition to 38 oral and 86 poster presentations, each technical session was opened by an invited national overview of research in major participating countries.

With the Navy's development of the integrated electric warship, large amounts of electrical energy will be made available, thus allowing the addition of pulsed weaponry and sensors. Electromagnetic railguns will increase the thermal load on such a ship by an order of magnitude or more over a conventional gun. To represent the expected loads, a numerical model has been created to simulate the system-level energy balance for a capacitive-based railgun system and is currently in development for a rotating machine-based system. In order to better study the system-level effects of the increased thermal burden, multiple shot profiles and scenarios were used. The simulation outputs are used as inputs to a ship-based, thermal management architecture built in the dynamic thermal software package Pro TRAX. Our analysis quantifies additional thermal management capacity that will be necessary for the future all-electric ship and provides the first step in simulating potential ship wide thermal management systems of pulsed loads in a dynamic sense. [ABSTRACT FROM AUTHOR]

The U.S. Navy is considering the development of electromagnetic railguns for future ships for naval surface-fire support (NSFS) and other missions. To reach long ranges, muzzle velocities in excess of 2000 m/s with projectile flight mass of 16 kg and above are needed. Relatively high firing rates are desired; typically 6-12 rounds per minute, so substantial power demands will be made on the ship. For an electrically driven ship, as in the DD(X) concepts presently being explored by the Navy, an existing electrical infrastructure would be in place that could be modified to recharge the pulsed power supplies for the railgun. This study focused on the railgun, the pulsed power, system needed to drive the gun, the power system needed to restore the energy required to match the firing rate, and special ship interfaces. Railgun concepts and sizing for the NSFS mission were undertaken, and research and development issues of importance for the success of a future system were identified. Recommendations for analytical and experimental studies that should be undertaken to further address these issues are provided. [ABSTRACT FROM AUTHOR]

A large-scale railgun is being considered by the U.S. Navy as a future long-range (>200 nm) naval weapon system. The notional concept includes a 15 kg projectile with a 2.5 km/s muzzle velocity. The choice of bore and rail geometry for such a weapon can influence, key aspects of the total system design. This study explored a range of bore and rail geometries and looked at their effects on key railgun system parameters such as parasitic mass, inductance gradient, linear current density, required pulse forming network (PFN) size, and barrel mass. Preliminary solid modeling and structural analysis of the integrated launch package was performed in order to quantify parasitic mass. Inductance gradient calculations were based on a current density distribution analysis. A PFN/launcher numerical simulation model was then used to determine linear current density and PFN size. Finally, barrel mass was estimated by structural analysis based on calculated rail repulsive forces. Trends and sensitivities of the different parameters to changes in the bore and rail geometries are presented and conclusions are given. [ABSTRACT FROM AUTHOR]

Describes a lightweight containment system for high-speed composite rotors developed at the University of Texas Center for Electromechanics in Austin. Uses of metallic flywheels; Failure modes and containment of flywheels; Purpose of the rotatable composite containment design.

Presents an overview of the evolution of compulsators (CPA) developed at the University of Texas at Austin Center for Electromechanics. Features of the CPA technology; Function of the CPA; Factors to be considered when designing a CPA.

Describes the parameters of a notional railgun design that may be capable of supporting the needs of the U.S. Navy, as of January 2003. Purpose of developing the electromagnetic (EM) railgun; Benefits of installing an EM railgun on a warship; Discussion on several technology issues that need to be addressed before the feasibility of the railgun system.

Describes the sensors developed at the University of Texas at Austin Center for Electromechanics to monitor speed, sense rotor position and detect fault condition. Features of the sensors; Performance requirements for the sensor; Information on current viewing resistor.

Describes the design algorithm used to optimize the railgun bore and integrated launch package at the University of Texas at Austin Center for Electromechanics (UT-CEM) in Arlington. Features of the UT-CEM design code; Development of an electric gun system design code; Fundamental categories used in the gun system.

Focuses on the developments in pulsed power technology which is used by the United States Army. Fundamental technical issues that need to be addressed in rotating machines; Drum rotor development; Composite structure evaluation; Creep and fatigue in composite/conductor interfaces.

Deals with a study on three generations of iron-core and air-core compensated pulsed alternators (CPA) conducted at the Center for Electromechanics at the University of Texas in Austin. Assumptions used in the point designs and comparisons; CPA design and performance; Switch design and performance.

Focuses on a study which discussed active magnetic bearings for energy storage systems for combat vehicles in the United States (U.S.). Details on the Combat Hybrid Power Systems program of the U.S. Department of Defense; Information on the bearing system design and bearing actuator design; Rotordynamic analysis; Bearing controller development; Control system performance evaluation; Test results.

Deals with a study which discussed several reasons why the United States Navy needs to develop electromagnetic (EM) guns. Projection of decisive levels of military power ashore; Limitations of three main categories of weapons used by the Navy; Information on EM gun research; Volume of fires produced by EM guns.

Presents an overview of the Cannon-Caliber Electromagnetic Gun (CCEMG) launcher design and describes the testing performed at University of Texas at Austin, Center for Electromechanics (UT-CEM) and U.S. Army Research Laboratory (ARL). Analysis on cannon-caliber design considerations; Discussion of testing the CCEMG by UT-CEM and ARL; Analysis on launcher performance and inspection; Conclusions.

Considers the cooling hole design in Bitter disks, a concept developed and tested at the National High Magnetic Field Laboratory (NHMFL). Background information on Bitter and polyhelix magnets; Cooling hole configuration; Application of the concept; Conclusions.

Presents an overview of the developments, related activities and applications of superconducting magnetic energy storage (SMES). Brief history of SMES development in the United States; Description of the SMES plant; Cost estimates of SMES development; Applications for SMES; Conclusions.

Focuses on a study on the approach of the United States Navy in developing an Electromagnetic Aircraft Launch System which is predicated on the state of the technology and expertise of the participants. Basic facts about the project; Information on a revised business model; Advantages of electromagnetic launch technology to future aircraft carriers.