Many next-generation air traffic algorithms may be formed by learning algorithms or dynamic programming techniques. These techniques form their solutions through iterative methods where the efficacy of a proposed solution needs to be evaluated for every round of iteration. In complex air traffic scenarios, often the only way to evaluate a proposed solution is to simulate the impact of the solution in an air traffic simulator. Such a simulator has to be fast enough to allow for many rounds of iteration. In addition, the simulator will have to be modular enough to allow modules to be created that simulate a portion of the airspace in detail.

Researchers at NASA's Armstrong Flight Research Center (AFRC) recently completed a study of the feasibility of aerial towing an unpiloted, sub-scale vehicle to supersonic flight conditions to examine the sonic boom that is produced — or, preferably, not produced.

A Launch Vehicle Adapter (LVA) was developed that provides a structural interface between a Commercial Crew Vehicle (CCV) Crew Module/Service Module Spacecraft (CM/SM) and an expendable launch vehicle. It also provides a means to control the exhaust plume from a pusher type launch abort system integrated into the Service Module.

Uncontrolled and rapid movement of equipment and people through security gates has been a major problem for security personnel. In situations pertaining to facility security, it is desirable to delay the passage of a person through an entrance or an exit for a small interval of time, such as several seconds or up to a minute. Often, authorization to proceed is provided by an electronic signal to unlock the passageway. Such electronic signals are initiated remotely by a person in authority, such as a guard in a control room viewing a security camera, or a person who verifies the identity of the requester through a two-way audio connection.

ARC2D is a computational fluid dynamics (CFD) program for two-dimensional airfoil and simply connected geometries. The program uses implicit finite-difference techniques to solve two-dimensional Euler equations and Navier-Stokes equations. It is based on the Beam and Warning implicit approximate factorization algorithm in generalized coordinates, in a variety of block or diagonal forms. The methods are either time-accurate (e.g., dual-time-stepping or Runge-Kutta methods) or accelerated non-time-accurate steady-state schemes. The evolution of the solution through time is physically realistic; good solution accuracy is dependent on mesh spacing and boundary conditions.

The scanning tunneling microscope (STM) has become one of the most powerful tools used in studying the surface structure of electrically conducting solid-state materials at an atomic resolution. Since its conception, the STM has had the greatest impact in the field of modern surface science because of its superior capability of characterizing and resolving the surface atomic structures and defects. Surface features such as atomic point defects, dislocations, and grain boundary identification can routinely be studied using a STM. Furthermore, STMs also allow the characterization of step structures at the atomic level during the processes of surface preparation and growth of semiconductors, such as epitaxial growth on semiconductor structures.

To produce accurate system architecture descriptions, it is essential to be able to describe interfaces between system elements at different levels of abstraction and from different perspectives at the same time. For example, the connection from system A to system B may be viewed at a high level as independent of the mechanisms that implement that flow (copper wire, free space RF, optical), and it may be useful to explore which of several of these mechanisms might be used. It is also frequently useful to analyze and constrain the problem (interface bindings) at several levels of detail (application protocols, network protocols, physical layer connections) separately, as well as in combination.

Traditional heat shield design isolates the functions of the thermal protection system (TPS) from the underlying load-carrying structure. This is due to the use of brittle TPS material that cannot carry the structural loads and that ablate during planetary entry. To isolate the TPS, the traditional approach has been to either bond a strain isolation pad between the TPS and structure or to design the structure significantly thick to eliminate bending loads transferred to the TPS. Adhesive is used to bond the TPS to the pad and/or structure. These bond lines can be a source of stress concentrations and manufacturing flaws.

This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.

Pegasus software is used as a pre-processor for overset-grid Computational Fluid Dynamics (CFD) simulations. It provides the hole-cutting and connectivity information between structured overset grids. The main features of the software include automated hole-cutting algorithms, a projection scheme for fixing small discretization errors in overset surface, efficient interpolation search methods, hole-size optimization based on adding additional layers of fringe points, and an automatic restart capability. The code can run in parallel using the Message-Passing Interface (MPI) standard.