The Pilot Weather Advisor (PWA) system is an automated satellite radio-broadcasting system that provides nearly realtime weather data to pilots of aircraft in flight anywhere in the continental United States. The system was designed to enhance safety in two distinct ways: First, the automated receipt...

The space shuttle orbiter's reaction control system (RCS) is a series of small thrusters that use hypergolic fuels to orient the orbiter in space. The RCS thrusters are constructed from a special niobium-based alloy — the C-103. This alloy retains excellent mechanical...

A simplified technique has been devised for fabricating helical antennas for use in experiments on radio-frequency generation and acceleration of plasmas. These antennas are typically made of copper (for electrical conductivity) and must have a specific helical shape and precise diameter.

A waveguide power-amplifier module capable of operating over the frequency range from 80 to 150 GHz has been constructed. The module comprises a previously reported power amplifier packaged in a waveguide housing that is compatible with WR-8 waveguides. (WR-8 is a standard waveguide size for the...

Graded-index-of- refraction dielectric optical microresonators have been proposed as a superior alternative to prior dielectric optical microresonators, which include microspheres (described in several prior NASA Tech Briefs articles) and microtori wherein electromagnetic waves...

ASelf-propagating high-temperature combustion synthesis (SHS) is the basis of a method of making components of porous tricalcium phosphate [Ca₃(PO₄)₂] and related compounds in net sizes and shapes for use as surgical implants that are compatible...

Mercury Laser Altimeter Science Algorithms is a software system for controlling the laser altimeter aboard the Messenger spacecraft, which is to enter into orbit about Mercury in 2011. The software will control the altimeter by dynamically modifying hardware inputs for gain, threshold, channel-...

DAVEtools is a set of Java archives (*.jar files) that embodies tools for manipulating flight-dynamics models that have been encoded in dynamic aerospace vehicle exchange markup language (DAVE-ML). [DAVE-ML is an application program, written in Extensible Markup Language (XML), for encoding complete computational models...

The Segment Alignment Maintenance System (SAMS) software is designed to maintain the overall focus and figure of the large segmented primary mirror of the Hobby-Eberly Telescope. This software reads measurements made by sensors attached to the segments of the primary mirror and from these...

Decelerator System Simulation (DSS) is a computer program for predicting and analyzing the dynamics of a load of cargo dropped with parachutes from an aircraft. A DSS simulation runs from the first motion in the aircraft until the payload reaches the ground. Intended for use in support of airdrop...

The Rational Sequence computer program described in the immediately preceding article includes a subprogram that utilizes the capability for aspect-oriented programming when that capability is present. This subprogram is denoted the Rational Sequence (AspectJ) component because it uses...

A computer program called "Rational Sequence" generates Universal Modeling Language (UML) sequence diagrams of a target Java program running on a Java virtual machine (JVM). Rational Sequence thereby performs a reverse engineering function that aids in the design documentation of the target Java program....

An updated computational model of the galactic-cosmic-ray (GCR) environment in the vicinity of the Earth, Earth's Moon, and Mars has been developed, and updated software has been developed to implement the updated model. The GCR model and software in their original forms, developed during the...

An enlarged, high-temperature -compliant foil bearing has been built and tested to demonstrate the feasibility of such bearings for use in aircraft gas turbine engines. At 150 mm in diameter, this is the largest foil bearing known to date. This bearing is a scaled-up version of a patented...

A method that involves the use of fictitious plate elements denoted bridge plates has been developed for representing the stiffnesses of fillets in finiteelement calculations of deflections, stresses, and strains in structures. In the absence of this method, it would be necessary to...

A document discusses the design of orbits of spacecraft for relaying communications between Earth stations and robotic and human explorers in craters in one of the polar regions on the Moon. In simplest terms, the basic problem is to design a constellation of orbits to provide continuous...