Physical Sciences

A report proposes a design concept for synthesizing a reflecting telescope with a large-aperture (diameter ≈100 m) primary mirror from a sparse arrangement of four smaller (diameter ≈10 m) primary mirrors. The telescope would be placed in orbit for viewing Earth with high resolution....

A report proposes a method to increase the accuracy of Doppler measurements made at the beginnings and endings of Earth/spacecraft radio occultations. Such measurements can reveal structural details of occulting objects in outer space. Heretofore, one-way measurements have been...

Infrared gas sensors that could be mass-produced at relatively low cost have been proposed for a variety of applications — for example, detecting carbon monoxide in air inside houses. A sensor of this type would include a housing into which ambient air could diffuse. The gas of...

Electrochemical cells in which molten carbonates would serve as electrolytes have been proposed for use in electrolyzing CO2. The proposal was made in an effort to implement a concept of in situ resource utilization (ISRU) for the exploration of Mars; the basic idea is to generate CO (if needed as...

An improved spherical energy analyzer (a type of electrostatic mass spectrometer) is under development for use in analyzing a beam of ions generated by a Hall thruster. The major improvement, relative to a commercial spherical energy analyzer, is the addition of a quadrupole stage (with refocusing electron optics)...

An oxygen-deficiency monitoring system (ODMS) has been developed for a ten-room facility in which the use of large amounts of nitrogen and helium could cause an oxygen deficiency severe enough to be hazardous to personnel. The ODMS comprises three subsystems, of which two monitor three rooms...

A report briefly describes a user's guide for a computer program that constructs vector wind profiles on the basis of a statistical model. The monthly vector wind profiles are meant to be used (1) to estimate wind-dispersion-related dispersions of critical aerodynamic loads and...

A report describes an experimental study of the sizes and concentrations of capped (buried) and surface In0.6Ga0.4As/GaAs quantum dots that were grown by metal-organic vapor deposition under the same conditions except for the inclusion or exclusion of capping. [InxGa1-xAs/GaAs quantum dots...

A report proposes the development of a thin-film fuel cell that would generate electric power from two minor constituents of the Martian atmosphere — O2 and CO. These compounds are generated continuously by photolysis of CO2, the major constituent. The fuel cell would include a cathode...

A miniature, battery-powered, semiautonomous environmental monitoring instrument contains advanced meteorological sensors, a Global Positioning System (GPS) receiver for determining its position, radio-communication circuitry, and a controller that performs measurement, control, and data-communication...

A proposed x-ray instrument - a Fourier-transform x-ray microscope - would enable high-resolution imaging of objects with sizes of the order of 20 nm. (This size range is typical of cell organelles.) The instrument would also offer a spectroscopic capability for the sensitive detection and identification of...

A proposal has been made to develop improved thin foil, replicated conical mirrors for use in x-ray astrophysics. In the NASA astrophysical programs in which such mirrors are used, they are required to be lightweight, and to offer moderate angular resolution and high throughput to afford required sensitivity in the...

The concept of free-flying micro-spacecraft was to develop a miniature spacecraft system fully integrated with a scientific sensor. A fleet of such tiny spacecraft would be deployed in space for multi-probe measurements of a three-dimensional phenomenon and to separate the spatial/temporal...

This report discusses direct numerical simulations (DNS) of a mixing layer, between a nitrogen stream and a heptane stream initially flowing at different velocities, under supercritical conditions and undergoing a transition to turbulence. Thermodynamically, supercritical conditions...

An improved automated system for transferring liquid helium from a supply tank to an end-use cryostat has been proposed. Like automated systems developed previously for the same purpose, this system would reduce the time that must be spent by technicians in replenishing cryostats in equipment...

The Newton-Euler Inverse Mass Operator (NEIMO) algorithm and software that implements the algorithm have been developed to reduce the amount of time needed to perform computational simulations of the dynamics of macromolecules. The NEIMO algorithm and the associated software are intended, in particular,...

A report presents a computational study of the subcritical and supercritical behaviors of a drop of heptane surrounded by nitrogen, using the fluid-drop model described in "Model of a Drop of O2 Surrounded by H2 at High Pressure" (NPO-20220) and "The Lewis Number Under Supercritical...

A report presents a computational study of the subcritical and supercritical behaviors of a drop of heptane surrounded by nitrogen. The subject matter is basically same as that of the report described in the preceding article, except that the Lewis-number issue is not addressed in detail; however, this...

This report presents an analysis of a database from computational simulations of a droplet-laden mixing layer (i.e., evaporating droplets of a liquid fuel in air) undergoing a transition to turbulence. The basic governing equations were those of transport of discrete droplets through a...

The report "A Validated All-Pressure Fluid Drop Model and Lewis Number Effects for a Binary Mixture" presents one in a series of theoretical and computational studies of the subcritical and subpercritical behaviors of a drop of fluid and, in particular, a drop of heptane surrounded by nitrogen The...

A report discusses direct numerical simulations (DNS) of a developing mixing layer between nitrogen and heptane initially at different temperatures and initially flowing at different velocities under supercritical conditions. The usual conservation equations for a binary fluid, along with the...

A system that samples gases at multiple remote locations and delivers the gases to two or possibly more gas-monitoring instruments (e.g., mass spectrometers) has been developed. The system includes a transport (suction) pump that draws the gases from the sampling locations, through transport...