Comparisons of winds at (44°S, 173°E), 65–110km,with CIRA 72

In the 95km height region of the atmosphere, ground-based techniques made an important contribution to the CIRA 72 [1] wind model. Recent wind measurements from a partial reflection experiment at 44S covering one and a half years are presented and compared with CIRA 72. The zonal wind component compares favourably, although the measured values are more easterly above 80km in autumn and winter; a feature of the autumn winds is a temporary easterly reversal above 90km. Winter mesospheric winds can be very disturbed. The summer mesosphere easterly maximum appears earlier in the season and at a higher altitude than the model. A much poorer comparison is shown between the measured meridional wind component and the 1969 model of Groves [2].     

Synopsis of D- and E-region electron densities during the energy budget campaign

Electron density profiles from ground based and rocket borne measurements are presented which were derived at three sites in northern Scandinavia under various degrees of geophysical disturbance. These data are checked against the instantaneous picture of the ionospheric absorption as observed with the dense riometer network.     

Image Correlation with Geometric Distortion Part II: Effect on Local Accuracy

The effect of geometric distortion on the local accuracy of the image registration algorithms using cross correlation is presented. Using a probabilistic model describing images as homogeneous random patterns, expressions for the mean and covariance of the local error vector in terms of image and noise autocorrelation functions, geometric distortion, and reference image area are derived. The geometric distortions considered are those represented by an affine transformation of image coordinates. It is shown that for a fixed geometric distortion there is an image size (integration area) that minimizes the local error. The optimum area decreases with increasing geometric distortion.     

Increased Aircraft Close-Support Mission Effectiveness Through Optimized Selection of Avionic Systems

The selection of avionic subsystems, which constitute an optimum integrated military aircraft electronic system, involves the analysis of three major factors: reliability, logistic compatibility, and performance. This is a discussion of the analysis of performance only, as an illustration of one major consideration in synthesizing a new aircraft avionic system. The quantitative result of this analysis would be combined with the results of analysis of the other two major factors for comparison with alternate systems similarly analyzed. One important type of close-support mission and its related avionic functions are described in terms of a required series of tasks, including navigation to the IP (identification point) and target, acquisition of the IP and target, and weapon delivery. The method of evaluating the avionic subsystems for their respective tasks is discussed, and the analytical method of evaluating system effectiveness is presented.     

The Swift Ultra-Violet/Optical Telescope

The Ultra-Violet/Optical Telescope (UVOT) is one of three instruments flying aboard the Swift Gamma-ray Observatory. It is designed to capture the early (∼1 min) UV and optical photons from the afterglow of gamma-ray bursts in the 170–600 nm band as well as long term observations of these afterglows. This is accomplished through the use of UV and optical broadband filters and grisms. The UVOT has a modified Ritchey–Chrétien design with micro-channel plate intensified charged-coupled device detectors that record the arrival time of individual photons and provide sub-arcsecond positioning of sources. We discuss some of the science to be pursued by the UVOT and the overall design of the instrument.     

A Semi-Empirical Approach to the PLL Threshold

This correspondence considers the response of the PLL near threshold to an input consisting of a modulated carrier and white, Gaussian noise. For high input signal-to-noise power ratios ?, the output noise power is Gaussian with a parabolic spectrum. As ? is decreased, the PLL tends to lose lock which gives rise to impulses or ?spikes? in the output with a resulting white power spectrum. The additional output noise due to these ?spikes? causes a threshold in the output signal-to-noise ratio. Unfortunately the loss of lock rate in the PLL depends on the modulation as well as the noise power. A semiempirical approximate expression for the loss of lock rate as a function of the noise and sinusoidal frequency modulation is presented and is used to determine the optimum design procedure for PLL's to demodulate FM signals of varying modulation indexes, ?.     

Progress in multilateral Earth observation cooperation: CEOS, IGOS and the ad hoc Group on Earth Observations

The Committee on Earth Observation Satellites (CEOS) coordinates international civil space-borne missions designed to observe and study planet Earth. With over 100 Earth observation satellites expected to be launched during the next 10 years, it is clear that collaborative opportunities have not been fully maximized. In 2003 CEOS has been focusing on articulating a more comprehensive satellite data utilization approach and in following up on its significant involvement in the World Summit on Sustainable Development. The CEOS Chair also serves as Co-Chair of the Integrated Global Observing Strategy (IGOS) Partnership, which seeks to reduce observation gaps and unnecessary overlaps and to harmonize and integrate common interests of space-based and in situ systems. IGOS focused in 2003 on development of a number of themes, including Carbon Cycle, Water Cycle and GeoHazards. The IGOS Ocean Theme is now in its implementation phase. NOAA, while chairing CEOS and co-chairing IGOS, has also been actively involved in organizing and hosting a ministerial-level Earth Observation Summit with a follow-on Group on Earth Observations (GEO) charged with developing the framework for a comprehensive global Earth observation system(s). All these activities demonstrate the commitment to developing more coherent and sustained Earth observation strategies for the good of the planet.     

Future spacelift projection

In 1996 the NASA Advisory Council asked for a comprehensive look at future launch projections out to the year 2030 and beyond. In response to this request NASA sponsored a study at The Aerospace Corporation to develop long-range space transportation models for future commercial and government applications, and to analyze the design considerations and desired characteristics for future space transportation systems. Follow-ons to present space missions as well as a wide array of potential new space applications are considered in the study. This paper summarizes the space transportation system characteristics required to enable various classes of future missions. High reliability and the ability to achieve high flight rates per vehicle are shown to be key attributes for achieving more economical launch systems. Technical, economic and policy implications are also discussed.     

A new goldfish model to evaluate pharmacokinetic and pharmacodynamic effects of drugs used for motion sickness in different gravity loads.

This paper proposes a new goldfish model to predict pharmacodynamic/pharmacokinetic effects of drugs used to treat motion sickness administered in differing gravity loads. The assumption of these experiments is that the vestibular system is dominant in producing motion sickness and that the visual system is secondary or of small import in the production of motion sickness. Studies will evaluate the parameter of gravity and the contribution of vision to the role of the neurovestibular system in the initiation of motion sickness with and without pharmacologic agents. Promethazine will be studied first. A comparison of data obtained in different groups of goldfish will be done (normal vs. acutely and chronically bilaterally blinded vs. sham operated). Some fish will be bilaterally blinded 10 months prior to initiation of the experiment (designated the chronically bilaterally blinded group of goldfish) to evaluate the neuroplasticity of the nervous system and the associated return of neurovestibular function. Data will be obtained under differing gravity loads with and without a pharmacological agent for motion sickness. Experiments will differentiate pharmacological effects on vision vs. neurovestibular input to motion sickness. Comparison of data obtained in the normal fish and in acutely and chronically bilaterally blinded fish with those obtained in fish with intact and denervated otoliths will differentiate if the visual or neurovestibular system is dominant in response to altered gravity and/or drugs. Experiments will contribute to validation of the goldfish as a model for humans since plasticity of the central nervous system allows astronauts to adapt to the altered visual stimulus conditions of 0-g. Space motion sickness may occur until such an adaptation is achieved.