An interactive computer program for sizing spacecraft momentum storage devices

An interactive computer program was developed which computes the sizing requirements for nongimbled reaction wheels, control moment gyros (CMG), and dual momentum control devices (DMCD) used in Earth-orbiting spacecraft. The program accepts as inputs the spacecraft's environmental disturbance torques, rotational inertias, maneuver rates, and orbital data. From these inputs, wheel weights are calculated for a range of radii and rotational speeds. The shape of the momentum wheel may be chosen to be either a hoop, solid cylinder, or annular cylinder. The program provides graphic output illustrating the trade-off potential between the weight, radius, and wheel speed. A number of the intermediate calculations such as the X-, Y-, and Z-axis total momentum, the momentum absorption requirements for reaction wheels, CMG's, DMCD's, and basic orbit analysis information are also provided as program output

Interplanetary sector structure, 1962 - 1966

Properties of interplanetary magnetic field observed by IMP-

A possible correlation between maxima of the far ultraviolet solar irradiance and central meridian passages of solar magnetic sector boundaries

Satellite observations of the sun over almost 5 yrs show that principally two UV active longitudes have persisted over a significant portion of this observational period. A comparison between the position of solar magnetic sector boundaries and UV enhancements of the sun seems to show, at least during the year 1969, that the UV maxima tend to occur near the times when a solar sector boundary is near central meridian. An estimate of the magnitude of the variable UV solar energy input into the atmosphere resulting from the rotation of active solar longitudes is that for wavelengths less than 175 nm and down to H Lyman-alpha it exceeds the annual variation, whereas at longer wavelengths it is less

Solar source of the interplanetary sector structure

Comparison of satellite interplanetary magnetic field observations with photospheric magnetic field and plage structur

Movie of the interplanetary magnetic field

Description of movie representing IMP-1 MAGNETOMETER observations of interplanetary magnetic fiel

Interplanetary magnetic field IMP-1, motion picture of the transverse components

Motion picture report of IMP-1 magnetometer observations of interplanetary magnetic fiel

A model of interplanetary and coronal magnetic fields

Model of interplanetary and solar magnetic field structure above photosphere using Green function solution to Maxwell equation

Tackling Challenges in Seebeck Coefficient Measurement of Ultra-High Resistance Samples with an AC Technique

Seebeck coefficient is a widely studied semiconductor property. Conventional Seebeck coefficient measurements are based on DC voltage measurement. Normally this is performed on samples with moderate resistances (e.g., below a few MΩ level). Certain semiconductors are intrinsic and highly resistive. Many examples can be found in optical and photovoltaic materials. The hybrid halide perovskites that have gained extensive attention recently are a good example. Despite great attention from the materials and physics communities, few successful studies exist of the Seebeck coefficient of these compounds, for example CH3NH3PbI3. An AC-technique-based Seebeck coefficient measurement is reported, which makes high-quality Seebeck voltage measurements on samples with resistances up to the 100 GΩ level. This is achieved through a specifically designed setup to enhance sample isolation and increase capacitive impedance. As a demonstration, Seebeck coefficient measurement of a CH3NH3PbI3 thin film is performed at dark, with sample resistance 150 GΩ, and found S = +550 µV K−1. The strategy reported could be applied to the studies of fundamental transport parameters of all intrinsic semiconductors that have not been feasible

Extension of the photospheric magnetic field into interplanetary space

Extension of photospheric magnetic field into interplanetary spac

Urban water reuse: A triple bottom line assessment framework and review

Water reuse networks have been emerging globally for the last 50 years. This article reviews the economic, social and environmental issues related to implementing water reuse networks in cities. This is reflecting the fact that globally many cities are categorised as water scarce areas, where there is growing imbalance between water demand and availability. In this sense, there is a need for sustainable water supply solutions in the imminent future to provide and maintain service reliability, particularly in the face of climate change. To demonstrate the sustainability implications of water reuse practices, we review a case study in London, UK