Keyword: Optimization

Briefs: Materials
Hybrid Wound Filaments for Greater Resistance to Impacts

The immediately preceding article includes an example in which a composite overwrap on a pressure vessel contains wound filaments made of a hybrid of high-strength carbon fibers and poly(phenylene benzobisoxazole) [PBO] fibers. This hybrid material is chosen in an effort to increase the...

Articles: Electronics & Computers

High-powered embedded computing equipment utilizing the Air Transport Rack (ATR) form factor is playing an ever-larger role in extreme, mission-critical applications in air, land, and sea...

Articles: Imaging

The Mobile & Marine Robotics Research Centre (MMRRC) at the University of Limerick in Ireland created a generic solution for underwater development. During...

Briefs: Information Technology

A framework for high-level specification of data distributions in data-parallel application programs has been conceived. [As used here, "distributions" signifies means to express...

Briefs: Materials
Foam Core Shielding for Spacecraft

A foam core shield (FCS) system is now being developed to supplant multilayer insulation (MLI) systems heretofore installed on spacecraft for thermal management and protection against meteoroid impacts. A typical FCS system consists of a core sandwiched between a face sheet and a back sheet. The core can...

Briefs: Information Technology
Implementation of a Point Algorithm for Real-Time Convex Optimization

The primal-dual interior-point algorithm implemented in G-OPT is a relatively new and efficient way of solving convex optimization problems. Given a prescribed level of accuracy, the convergence to the optimal solution is guaranteed in a predetermined, finite number of...

Briefs: Information Technology
GVIPS Models and Software

Two reports discuss, respectively, (1) the generalized viscoplasticity with potential structure (GVIPS) class of mathematical models and (2) the Constitutive Material Parameter Estimator (COMPARE) computer program. GVIPS models are constructed within a thermodynamics- and potential-based theoretical framework, wherein...

Briefs: Electronics & Computers
Wide Tuning Capability for Spacecraft Transponders

A document presents additional information on the means of implementing a capability for wide tuning of microwave receiver and transmitter frequencies in the development reported in the immediately preceding article, "VCO PLL Frequency Synthesizers for Spacecraft Transponders" (NPO-42909). The...

Briefs: Information Technology
Estimating the Inertia Matrix of a Spacecraft

A paper presents a method of utilizing some flight data, aboard a spacecraft that includes reaction wheels for attitude control, to estimate the inertia matrix of the spacecraft. The required data are digitized samples of (1) the spacecraft attitude in an inertial reference frame as measured, for...

Briefs: Physical Sciences

The terminal descent sensor (TDS) is a radar altimeter/velocimeter that improves the accuracy of velocity sensing by more than an order of magnitude when compared to existing sensors. The TDS is designed...

Briefs: Information Technology

A method of approximating a scalar function of n independent variables (where n is a positive integer) to arbitrary accuracy has been developed. This method is expected to be...

Briefs: Software
Designing Rolling-Element Bearings

Bearing Analysis Tool (BAT) is a computer program for designing rolling-element bearings for cryogenic turbomachines. BAT provides a graphical user interface (GUI) that guides the entry of data to develop mathematical models of bearings. The GUI breaks model data into logical subsets that are entered through...

Briefs: Software

The Flyby Geometry Optimization Tool is a computer program for computing trajectories and trajectory-altering impulsive maneuvers for spacecraft used in radio relay of scientific data to Earth from an...

Briefs: Software
Parallel Computing With Satellite Orbit Analysis Program

This software innovation speeds up the computation time of the Satellite Orbit Analysis Program (SOAP) tool by parallelizing the code using the message- passing interface (MPI) library. The speed increases almost linearly with the number of processors, allowing the perstudy duration of the...

Briefs: Materials

Norbornene-based polymers have shown promise as solid electrolytes for lithium-based rechargeable electrochemical cells. These polymers are characterized as single-ion conductors.

Briefs: Mechanical & Fluid Systems
Efficient Optimization of Low-Thrust Spacecraft Trajectories

A paper describes a computationally efficient method of optimizing trajectories of spacecraft driven by propulsion systems that generate low thrusts and, hence, must be operated for long times. A common goal in trajectory-optimization problems is to find minimum-time, minimum-fuel, or...

Briefs: Electronics & Computers
Cylindrical Asymmetrical Capacitors for Use in Outer Space

A report proposes that cylindrical asymmetrical capacitors (CACs) be used to generate small thrusts for precise maneuvering of spacecraft on long missions. The report notes that it has been known for decades that when high voltages are applied to CACs in air, thrusts are generated —...

Briefs: Mechanical & Fluid Systems
Algorithm Optimally Allocates Actuation of a Spacecraft

A report presents an algorithm that solves the following problem: Allocate the force and/or torque to be exerted by each thruster and reaction-wheel assembly on a spacecraft for best performance, defined as minimizing the error between (1) the total force and torque commanded by the...

Briefs: Information Technology
A Robustly Stabilizing Model Predictive Control Algorithm

A model predictive control (MPC) algorithm that differs from prior MPC algorithms has been developed for controlling an uncertain nonlinear system. This algorithm guarantees the resolvability of an associated finite-horizon optimal-control problem in a receding horizon implementation....

Articles: Electronics & Computers

MicroTCA is a new specification that offers very high performance packed in a small form factor. The new specification is expected to be used in a wide variety of applications, including mil/aero, telecom...

Briefs: Photonics/Optics

A carrier structure made from a single silicon substrate is the basis of a compact, lightweight, relatively inexpensive package that holds the main optical/electronic coupling components...

Briefs: Physical Sciences

A phase-diverse iterative-transform phase-retrieval algorithm enables high-spatial-frequency, high-dynamic-range, image-based wavefront sensing. [The terms "phase-diverse," "phase...

Articles: Electronics & Computers

With the introduction of Intel Core microarchitecture into embedded systems, history could very well repeat itself. The company that invented the microprocessor in 1971 and created the...

Briefs: Software
Translator for Optimizing Fluid-Handling Components

A software interface has been devised to facilitate optimization of the shapes of valves, elbows, fittings, and other components used to handle fluids under extreme conditions. This software interface translates data files generated by PLOT3D (a NASA grid-based plotting-and- data-display...

Briefs: Physical Sciences

Experiments have shown that with suitable choices of critical dimensions, planar arrays of bundles of carbon nanotubes (see figure) can serve as high-current-density field emitter...

Briefs: Electronics & Computers

A portable long-wavelength infrared electronic camera having a cutoff wavelength of 9 μm has been built around an image sensor in the form of a 640 × 512- pixel array of...

Briefs: Physical Sciences

A method of compensation for the polarization-dependent phase anisotropy of a metal reflector has been proposed. The essence of the method is to coat the reflector with multiple thin...

Briefs: Information Technology
Decision-Tree Formulation With Order-1 Lateral Execution

A compact symbolic formulation enables mapping of an arbitrarily complex decision tree of a certain type into a highly computationally efficient multidimensional software object. The type of decision trees to which this formulation applies is that known in the art as the Boolean class of...

Briefs: Mechanical & Fluid Systems

A system for mechanical suspension and vibration isolation of a machine or instrument is based on the use of Kevlar (or equivalent aromatic polyamide) cord held in variable tension...