Detection of the high energy component of Jovian electrons in Low Earth Orbit with the PAMELA experiment

The PAMELA experiment is devoted to the study of cosmic rays in Low Earth Orbit with an apparatus optimized to perform a precise determination of the galactic antimatter component of c.r. It is constituted by a number of detectors built around a permanent magnet spectrometer. PAMELA was launched in space on June 15th 2006 on board the Russian Resurs-DK1 satellite for a mission duration of 3 years. The characteristics of the detectors, the long lifetime and the orbit of the satellite, will allow to address several aspects of cosmic-ray physics. In this work we discuss the observational capabilities of PAMELA to detect the electron component above 50 MeV. The magnetic spectrometer allows a detailed measurement of the energy spectrum of electrons of galactic and Jovian origin. Long term measurements and correlations with Earth–Jupiter 13 months synodic period will allow to separate these two contributions and to measure the primary electron Jovian component, dominant in the 50–70 MeV energy range. With this technique it will also be possible to study the contribution to the electron spectrum of Jovian e⁻ reaccelerated up to 2 GeV at the Solar Wind Termination Shock.     

Sociotechnical Systems Evolution and International Stability: 1885-2001

A number of evolutionary sociotechnical patterns associated with the intensification of warfare and movement of the international system into a domain far from equilibrium are discussed. Evolution is extended from the past 100 years to the end of the 20th century with the identification of several likely crises precipitatory to World War III. Systems theoretic interpretation of a number of evolutionary developments is made. The use of systems concepts and systems experts in the management of international stability is discussed further.     

Guided propagation of HF radio waves in the ionosphere

A review is given of the work done in the field of ionospheric guided propagation of HF radio signals from artificial satellites. The possible theoretical approaches to the problem are summarized with more details on the analysis in terms of ray-tracing based on a geometric-optics treatment.A survey is done of the experimental observations performed through satellite transmissions, with particular emphasis on the results obtained through three ad hoc developed experiments: Orbis, S. Marco and OV 4.     

Effect of Random Synchronization Errors in PN and PSK Systems

The effect of a constant synchronization error on PN systems has been studied by Gill [1]. His results are generalized here for random synchronization errors, and extended to PSK systems using decision directed channel measurements [2]. In both cases, it is shown that the effect of random synchronization errors is to reduce the effective input signal power and to introduce an additional self-noise. The effect is minimized when the synchronization error has zero mean and can easily be evaluated in terms of circuit parameters.     

A new dynamical atmospheric ionizing radiation (AIR) model for epidemiological studies.

A new Atmospheric Ionizing Radiation (AIR) model is currently being developed for use in radiation dose evaluation in epidemiological studies targeted to atmospheric flight personnel such as civilian airlines crewmembers. The model will allow computing values for biologically relevant parameters, e.g. dose equivalent and effective dose, for individual flights from 1945. Each flight is described by its actual three dimensional flight profile, i.e. geographic coordinates and altitudes varying with time. Solar modulated primary particles are filtered with a new analytical fully angular dependent geomagnetic cut off rigidity model, as a function of latitude, longitude, arrival direction, altitude and time. The particle transport results have been obtained with a technique based on the three-dimensional Monte Carlo transport code FLUKA, with a special procedure to deal with HZE particles. Particle fluxes are transformed into dose-related quantities and then integrated all along the flight path to obtain the overall flight dose. Preliminary validations of the particle transport technique using data from the AIR Project ER-2 flight campaign of measurements are encouraging. Future efforts will deal with modeling of the effects of the aircraft structure as well as inclusion of solar particle events.     

A Survey of Field-Aligned Mach Number and Plasma Beta in the Solar Wind

We have surveyed solar wind plasma beta and field-aligned Alfvénic Mach number using Ulysses and Wind data. We show the characteristic timescale and occurrence frequency of ‘magnetically dominated’ solar wind, whose interaction with a planetary magnetosphere may produce a bow shock with multiple shock fronts. We discuss radial, latitudinal, and solar cycle effects. This revised version was published online in August 2006 with corrections to the Cover Date.     

Extragalactic observations and future missions

We briefly review some questions of extragalactic astrophysics and cosmology that would most benefit from future missions outside the Earth's atmosphere in the IR and submillimeter. These include the formation and early evolution phases in galaxies and the probably related question of quasar formation; the observation of Active Galactic Nuclei embedded in thick dusty structures (torii) and its impact on the still debated unified model of AGN activity; the observability of radiation processes occurring at very highz through background measurements; the investigation of the large scale structure and velocity field in the distant universe; and studies of the interstellar medium in galaxies. Some more emphasis is given on the galaxy formation problem, because we believe that IR-mm sensitive observations will be crucial to its final solution.     

Experimental and theoretical extinction of solid rocket propellants by fast depressurization

Dynamic burning of solid rocket propellants following fast depressurization of the combustion chamber was studied experimentally. Extinction boundaries were constructed for different sets of values of the controlling parameters (such as initial pressure, final pressure and depressurization rate). Most experimental results were collected by testing a nonmetallized, ammonium perchlorate based, composite propellant (AP83/CTPB16/Al₂O₃). Experimental results show that, for a given final pressure, an extinction boundary in terms of maximum depressurization rate vs initial pressure can be constructed by go/no-go testing. The objective was to check experimentally the analytical predictions of dynamic extinction boundaries obtained by this research group for finite size disturbances. A good agreement was found between analytical, numerical, and experimental results.     

New generation of infrared horizon scanning sensors for low altitude spacecraft

The STD 12 infrared horizon scanning sensor is designed for attitude control, with respect to Earth, of three-axis stabilized satellites in low altitude Earth orbits. The operational accuracy is better than 0.1 arc degree.After presenting the attitude measurement performance required for the SPOT platform, the STD 12 concept is described and the results of qualification and life tests are given.