Wind-field analysis on the basis of METEOSAT images

A method for the determination of cloud motion vectors is proposed by calculating from METEOSAT images the displacement of characteristic formations in the brightness field. The claculations are made for a sector of the Atlantic Ocean (ψ = 48°?38°N, λ = 24°?12°W). The adaptability of the Soebel operator for such calculations is also shown. The calculated wind vectors are in a good agreement with wind data at 850 mb surface.     

Connections between short-period (Pc 1) pulsations and ionospheric parameters

Short-period pulsations recorded at five stations in Finland during the IMS have been compared. The morning occurrences accepted as Pc 1's showed certain peculiarities in their dependence on latitude. A connection was found between the averaged daily duration of Pc 1's and the foF2 parameter. This hints at the influence of propagation conditions. It was found that, after certain geomagnetic storms, the mid-latitude ionospheric absorption of LF radio waves can significantly increase when the Pc 1 activity is also enhanced at each high-latitude station.     

High energy density capacitors for space power conditioning

Several advanced capacitor designs that might be used in high average power space applications are described. Each type is fundamentally limited by breakdown phenomena. All are intrinsically limited to maximum fields on the order of 1000 MV/m. None of these units has been space rated for energy storage applications. Several problems that must be solved before use in space are presented as well as the current state of the art and estimates of developmental potential     

Dynamics of the dayside aurora

Observations of auroral particles by rockets and satellites show the existence of structured “inverted V” type precipitation events with electron characteristic energies ranging up to several hundred eV in the post-noon dayside auroral region. Two station ground-based measurements from Cape Parry, NWT and Sachs Harbour, NWT, Canada from meridian scanners and auroral all-sky TV cameras are used in conjunction with rocket-borne electron measurements to study the temporal and spatial characteristics of the associated auroral emissions. The frequent occurrence of narrow, transient auroral arcs with lifetimes of 1–2 minutes, resulting from the inverted V events, is discussed.     

Computerizing the circuit board industry while reducing costs

The author examines a systems approach to automation that the printed circuit board (PCB) manufacturer can use in order to adapt today's technology for his or her individual needs. He begins with an overview of production functions. He then describes the subsystems approach, the steps leading to computerization, implementation, the bare board test system, and preprocessing     

Astronautics and psychology: recommendations for the psychological training of astronauts

The methods presently applied in the psychological training of astronauts are based on the principle of ensuring maximum performance of astronauts during missions. The shortcomings are obvious since those undergoing training provide nothing but the best ability to cope with Earth problem situations and add simply an experience of space problem situations as they are presently conceived. Earth attitudes and Earth behaviour remain and are simply modified. Through the utilization of interdisciplinary space knowledge a much higher degree of problem anticipation could be achieved and the astronaut be psychologically transformed into a space-being. This would at the same time stimulate interdisciplinary space research. The interdisciplinary space knowledge already available suggests that space requires not only physical and mental adjustments, but a profoundly new relationship with life.     

Optimum Filters for Image Registration

Two-dimensional cross-correlation techniques are applied to the problem of image registration under the assumption of small geometric distortion. Optimum filter functions for use with arbitrary window functions are derived for two performance measures of interest: peak-to-sidelobe ratio, and mean- square registration error; the latter is examined in terms of the contribution due to distortion and the contribution due to noise. A generalized Lagrange multiplier approach is used to derive at least approximate ate solutions to the case where the images are modeled as random processes and to the case where the images are assumed to be deterministic.     

On Identifying Transfer Functions and State Equations for Linear Systems

Two methods are established for identifying constantcoefficient C2n-type noise-free linear systems if the time response data of the input-output or of all states are known. 2n response data are required to identify an nth-order transfer function or state equation for an unknown linear system. The order of the unknown system can be identified by checking a sequence of determinants. The Z transform and its inversion are mainly used.     

Magnetospheric and Plasma Science with Cassini-Huygens

Magnetospheric and plasma science studies at Saturn offer a unique opportunity to explore in-depth two types of magnetospheres. These are an ‘induced’ magnetosphere generated by the interaction of Titan with the surrounding plasma flow and Saturn's ‘intrinsic’ magnetosphere, the magnetic cavity Saturn's planetary magnetic field creates inside the solar wind flow. These two objects will be explored using the most advanced and diverse package of instruments for the analysis of plasmas, energetic particles and fields ever flown to a planet. These instruments will make it possible to address and solve a series of key scientific questions concerning the interaction of these two magnetospheres with their environment. The flow of magnetospheric plasma around the obstacle, caused by Titan's atmosphere/ionosphere, produces an elongated cavity and wake, which we call an ‘induced magnetosphere’. The Mach number characteristics of this interaction make it unique in the solar system. We first describe Titan's ionosphere, which is the obstacle to the external plasma flow. We then study Titan's induced magnetosphere, its structure, dynamics and variability, and discuss the possible existence of a small intrinsic magnetic field of Titan. Saturn's magnetosphere, which is dynamically and chemically coupled to all other components of Saturn's environment in addition to Titan, is then described. We start with a summary of the morphology of magnetospheric plasma and fields. Then we discuss what we know of the magnetospheric interactions in each region. Beginning with the innermost regions and moving outwards, we first describe the region of the main rings and their connection to the low-latitude ionosphere. Next the icy satellites, which develop specific magnetospheric interactions, are imbedded in a relatively dense neutral gas cloud which also overlaps the spatial extent of the diffuse E ring. This region constitutes a very interesting case of direct and mutual coupling between dust, neutral gas and plasma populations. Beyond about twelve Saturn radii is the outer magnetosphere, where the dynamics is dominated by its coupling with the solar wind and a large hydrogen torus. It is a region of intense coupling between the magnetosphere and Saturn's upper atmosphere, and the source of Saturn's auroral emissions, including the kilometric radiation. For each of these regions we identify the key scientific questions and propose an investigation strategy to address them. Finally, we show how the unique characteristics of the CASSINI spacecraft, instruments and mission profile make it possible to address, and hopefully solve, many of these questions. While the CASSINI orbital tour gives access to most, if not all, of the regions that need to be explored, the unique capabilities of the MAPS instrument suite make it possible to define an efficient strategy in which in situ measurements and remote sensing observations complement each other. Saturn's magnetosphere will be extensively studied from the microphysical to the global scale over the four years of the mission. All phases present in this unique environment — extended solid surfaces, dust and gas clouds, plasma and energetic particles — are coupled in an intricate way, very much as they are in planetary formation environments. This is one of the most interesting aspects of Magnetospheric and Plasma Science studies at Saturn. It provides us with a unique opportunity to conduct an in situ investigation of a dynamical system that is in some ways analogous to the dusty plasma environments in which planetary systems form. This revised version was published online in August 2006 with corrections to the Cover Date.