Keyword: Mechanics

Mechanical & Fluid Systems

Briefs: Mechanical & Fluid Systems

A proposed three degree of freedom (tilt/tip/piston) manipulator, suitable for aligning an optical or mechanical component, would offer several advantages over prior such...

Briefs: Mechanical & Fluid Systems
Multifunctional Tanks for Spacecraft

A document discusses multifunctional tanks as means to integrate additional structural and functional efficiencies into designs of spacecraft. Whereas spacecraft tanks are traditionally designed primarily to store fluids and only secondarily to provide other benefits, multifunctional tanks are designed to...

Briefs: Mechanical & Fluid Systems

The Planetary Autonomous Amphibious Robotic Vehicle (PAARV), now at the prototype stage of development, was originally intended for use in acquiring and analyzing samples of solid,...

Briefs: Mechanical & Fluid Systems

A system for automated sampling of rocks, ice, and similar hard materials at and immediately below the surface of the ground is undergoing development. The system, denoted a sample...

Briefs: Mechanical & Fluid Systems

An improved process for making nanocrystallites, commonly denoted quantum dots (QDs), is based on spray pyrolysis. Unlike the process used heretofore, the improved process is amenable to mass...

Briefs: Mechanical & Fluid Systems

A tool makes it possible to couple a torque wrench to an externally knurled, internally threaded, round cable connector. The purpose served by the tool is to facilitate the...

Briefs: Mechanical & Fluid Systems
Controlling Attitude of a Solar-Sail Spacecraft Using Vanes
A paper discusses a concept for controlling the attitude and thrust vector of a three-axis stabilized Solar Sail spacecraft using only four single degree of freedom articulated spar-tip vanes. The vanes, at the corners of the sail, would be turned to commanded angles about the diagonals of...
Briefs: Mechanical & Fluid Systems

An ultrasonic rock-abrasion tool (URAT) was developed using the same principle of ultrasonic/sonic actuation as that of the tools described in two prior NASA Tech Briefs articles:...

Briefs: Mechanical & Fluid Systems

Controllable active struts that would function as linear actuators with variable spring stiffness and damping have been proposed as components of advanced suspension systems of future...

Briefs: Mechanical & Fluid Systems

A technique for real-time estimation of stability and control derivatives (derivatives of moment coefficients with respect to control-surface deflection angles) was used to support a...

Briefs: Mechanical & Fluid Systems

A flight test on an F-15 airplane was performed to evaluate the utility of prescribed simultaneous independent surface excitations (PreSISE) for real-time estimation of flight-control...

Briefs: Mechanical & Fluid Systems
Integral Flexure Mounts for Metal Mirrors for Cryogenic Use

Semi-kinematic, six-degree-of-freedom flexure mounts have been incorporated as integral parts of metal mirrors designed to be used under cryogenic conditions as parts of an astronomical instrument. The design of the mirrors and their integral flexure mounts can also be adapted to other...

Briefs: Mechanical & Fluid Systems
Low-Cost Propellant Launch From a Tethered Balloon

A document presents a concept for relatively inexpensive delivery of propellant to a large fuel depot in low orbit around the Earth, for use in rockets destined for higher orbits, the Moon, and for remote planets. The propellant is expected to be at least 85 percent of the mass needed in low...

Briefs: Mechanical & Fluid Systems

The variable terrain tilt platform (VTTP) is a means of providing simulated terrain for mobility testing of engineering models of the Mars Exploration Rovers. The VTTP could also be...

Briefs: Mechanical & Fluid Systems
On Release of Microbe-Laden Particles From Mars Landers

A paper presents a study in which rates of release of small particles from Mars lander spacecraft into the Martian atmosphere were estimated from first principles. Because such particles can consist of, or be laden with, terrestrial microbes, the study was undertaken to understand their...

Briefs: Mechanical & Fluid Systems
Stable Satellite Orbits for Global Coverage of the Moon

A document proposes a constellation of spacecraft to be placed in orbit around the Moon to provide navigation and communication services with global coverage required for exploration of the Moon. There would be six spacecraft in inclined elliptical orbits: three in each of two orthogonal...

Briefs: Mechanical & Fluid Systems

Designers often turn to self-clinching fasteners when they need a practical method to provide threads in thin metal sheets. The fasteners install permanently, reduce hardware, and promote thinner...

Briefs: Mechanical & Fluid Systems

Shapes different from the traditional ones have been proposed for face worm gears and for conical and cylindrical worms that mesh with them. The proposed shapes are based on the concept of...

Briefs: Mechanical & Fluid Systems
Using Plates To Represent Fillets in Finite-Element Modeling

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...

Briefs: Mechanical & Fluid Systems
Lunar Constellation of Frozen Elliptical Inclined Orbits

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...

Briefs: Mechanical & Fluid Systems
Two High-Temperature Foil Journal Bearings

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...

Briefs: Mechanical & Fluid Systems

A nonlinear version of the Liouville equation based on terminal attractors is part of a mathematical formalism for describing postinstability motions of dynamical systems...

Briefs: Mechanical & Fluid Systems
Controlling Herds of Cooperative Robots

A document poses, and suggests a program of research for answering, questions of how to achieve autonomous operation of herds of cooperative robots to be used in exploration and/or colonization of remote planets. In a typical scenario, a flock of mobile sensory robots would be deployed in a previously...

Briefs: Mechanical & Fluid Systems

The figure shows the LEMUR IIb, which is a modified version of the LEMUR II — the second generation of the Limbed Excursion Mechanical Utility Robot (LEMUR). Except as described below,...

Briefs: Mechanical & Fluid Systems
Compact, Precise Inertial Rotation Sensors for Spacecraft

A document describes a concept for an inertial sensor for measuring the rotation of an inertially stable spacecraft around its center of gravity to within 100 microarc- seconds or possibly even higher precision. Whereas a current proposal for a spacecraft-rotation sensor of this accuracy...

Briefs: Mechanical & Fluid Systems
Cargo-Positioning System for Next-Generation Spacecraft

A report discusses a proposed system for mounting loaded pallets in the cargo bay of a next-generation space-shuttle-like spacecraft, such that the center of mass of the cargo would lie within a 1-in. (2.54- cm) cube that would also contain the center of mass of the spacecraft. The system...

Briefs: Mechanical & Fluid Systems

In the continuing goal of developing products with better performance at a lower cost, composites are becoming increasingly prevalent in the...

Briefs: Mechanical & Fluid Systems
Large Deployable Reflectarray Antenna

A report discusses a 7-meter-diameter reflectarray antenna that has been conceived in a continuing effort to develop large reflectarray antennas to be deployed in outer space. Major underlying concepts were reported in three prior NASA Tech Briefs articles: "Inflatable Reflectarray Antennas" (NPO-20433),...

Briefs: Mechanical & Fluid Systems

A proposed device would remove bubbles of gas from a stream of liquid (typically water), accumulate the gas, and periodically release the gas, in bulk, back into the stream. The device is...