Kinematics of rigid bodies in spaceflight

Rigid rotating body kinematic equations for use in space flight mechanic

Comparison of storm-time changes of geomagnetic field at ground and at MAGSAT altitudes

Computations concerning variations of the geomagnetic field at MAGSAT altitudes were investigated. Using MAGSAT data for the X, Y, and Z components of the geomagnetic field, a computer conversion to yield the H component was performed. Two methods of determining delta H normalized to a constant geocentric distance R sub 0 = 6800 were investigated, and the utility of elta H at times of magnetic storms was considered. Delta H at a geographical latitude of 0 at dawn and dusk, the standard Dst, and K sub p histograms were plotted and compared. Magnetic anomalies are considered. Examination of data from the majority of the 400 passes of MAGSAT considered show a reasonable delta H versus latitude variation. Discrepancies in values are discussed

Pitch and yaw motions of a human being in free fall

Human limb motions for body orientation during free fal

Alteration of the state of motion of a human being in free fall

Orientation and attitude alteration of human body motion state in free fall studied with mathematical model

Evolution of geomagnetic <i>aa</i> index near sunspot minimum

International audienceThe smoothed values of the minima of sunspot number Rz and the geomagnetic index aa were compared for sunspot cycles 12?23. In one cycle, aa(min) occurred earlier than Rz(min), but remained at that low from a few months before Rz(min) to a few months after Rz(min). In two cycles, Rz(min) and aa(min) coincided within a month or two. In nine cycles, aa(min) occurred more than three months later than Rz(min). The aa(min) coincided with the minima of some solar radio emission indices originating in the solar corona. For sunspot cycles 21, 22, 23, the minimum of solar wind velocity V occurred 0?9 months later than the aa(min). The minimum of solar wind total magnetic field B occurred near Rz(min). The solar wind ion density N had maxima (instead of minima) near Rz(min), and again near Rz(max), indicating a ~5-year periodicity, instead of an 11-year periodicity. The maxima of aa, V and B occurred near Rz(max) and/or later in the declining phase of Rz. The aa index was very well correlated with the functions BV and BV 2

Evolutions of various solar indices around sunspot maximum and sunspot minimum years

International audienceThe smoothed monthly sunspot numbers showed that in many solar cycles, (a) during years around sunspot maxima, there was only one prominent maximum, but in some cycles there was a broad plateau. If the beginning and end of these are termed as first and second maxima (separated by several months), the first maximum was generally the higher one, and the valley in between was very shallow. Solar indices at or near the photosphere generally showed similar structures with maxima matching with sunspot maxima within a month or two. Indices originating in the chromosphere and above showed two peaks in roughly the same months as sunspots (with some exceptions, notably the Coronal green line, and the Total Solar Irradiance). Yet often, the second maximum was larger than the first maximum, and the valley between the two maxima was deeper, as compared to sunspot maxima, and (b) during years around sunspot minima, the smoothed sunspot minimum could be sharp and distinct, lasting for a month or two, or could spread over several months. Among the indices originating at or near the photosphere, the Ca K line intensity showed good matching with sunspots, but the Ca Plage area, the Sunspot Group Area, and the solar magnetic fields seemed to show minima earlier than the sunspots, indicating that these activities died out first. These also showed recoveries from the minima later than sunspots. Most of the other indices originating in the chromosphere and corona attained minima coincident with sunspot minima, but in some cases, minima earlier than sunspots were seen, while in some other cases minima occurred after the sunspot minima. Thus, the energy dissipation in the upper part of the solar atmosphere sometimes lagged or led the evolution of sunspots near sunspot minimum. In a few cases, after the minimum, the indices recovered faster than the sunspots. In general, the chromospheric indices seemed to evolve similar to sunspots, but the evolution of coronal indices was not always similar to sunspots, and may differ considerably between themselves

Simulations for Multi-Object Spectrograph Planet Surveys

Radial velocity surveys for extra-solar planets generally require substantial amounts of large telescope time in order to monitor a sufficient number of stars. Two of the aspects which can limit such surveys are the single-object capabilities of the spectrograph, and an inefficient observing strategy for a given observing window. In addition, the detection rate of extra-solar planets using the radial velocity method has thus far been relatively linear with time. With the development of various multi-object Doppler survey instruments, there is growing potential to dramatically increase the detection rate using the Doppler method. Several of these instruments have already begun usage in large scale surveys for extra-solar planets, such as FLAMES on the VLT and Keck ET on the Sloan 2.5m wide-field telescope. In order to plan an effective observing strategy for such a program, one must examine the expected results based on a given observing window and target selection. We present simulations of the expected results from a generic multi-object survey based on calculated noise models and sensitivity for the instrument and the known distribution of exoplanetary system parameters. We have developed code for automatically sifting and fitting the planet candidates produced by the survey to allow for fast follow-up observations to be conducted. The techniques presented here may be applied to a wide range of multi-object planet surveys.Comment: 15 pages, 10 figures, accepted for publication in MNRA

Comparison of storm-time changes of geomagnetic field at ground and MAGSAT altitudes

The MAGSAT data for the period Nov. 2-20, 1979 were studied. From the observed H, the HMD predicted by model was subtracted. The residue delta H = H-HMD shows storm-time variations similar to geomagnetic Dst, at least qualitatively. Delta H sub 0, i.e., equatorial values of delta H were studied separately for dusk and dawn and show some differences

Comparison of storm-time changes of geomagnetic field at ground and at MAGSAT altitudes, part 3

The latitudinal distributions of delta H, delta X, delta Y, and delta Z were studied for quiet and disturbed periods. For quiet periods, the average patterns showed some variations common to dusk and dawn, thus indicating probable ground anomaly. However, there were significant differences too between dusk and dawn, indicating considerable diurnal variation effects. Particularly in delta Y, these effects were large and were symmetric about the dip equator. For disturbed day passes, the quiet day patterns were considered as base levels and the latter were subtracted from the former. The resulting residual latitudinal patterns were, on the average, symmetric about the geographical equator. However, individual passes showed considerable north-south asymmetries, probably indicating meanderings of the central plane of the magnetospheric ring current