60 GHz FM-CWR Using NRD guide for distance estimation

An FM-CW radar front-end was fabricated in an integrated manner at 60 GHz by using the NRD guide. The main emphasis was placed on compactness in size and high-precise operation in performance. The fabricated radar consists of an FM Gunn oscillator, a balanced mixer, and a planar antenna fed by a leaky NRD guide with a mechanically beam-scanning performance. All circuit components and the antenna were contained in a compact housing of 170 x 140 mm in area and 25 mm in thickness, and thus, a thin type of millimeter-wave radar front-end was successfully developed. Moreover, an error of distance estimation was measured to be less than a distance of 0.7 m.     

The Solar Isotope Spectrometer for the Advanced Composition Explorer

The Solar Isotope Spectrometer (SIS), one of nine instruments on the Advanced Composition Explorer (ACE), is designed to provide high- resolution measurements of the isotopic composition of energetic nuclei from He to Zn (Z=2 to 30) over the energy range from ∼10 to ∼100 MeV nucl−1. During large solar events SIS will measure the isotopic abundances of solar energetic particles to determine directly the composition of the solar corona and to study particle acceleration processes. During solar quiet times SIS will measure the isotopes of low-energy cosmic rays from the Galaxy and isotopes of the anomalous cosmic-ray component, which originates in the nearby interstellar medium. SIS has two telescopes composed of silicon solid-state detectors that provide measurements of the nuclear charge, mass, and kinetic energy of incident nuclei. Within each telescope, particle trajectories are measured with a pair of two-dimensional silicon-strip detectors instrumented with custom, very large-scale integrated (VLSI) electronics to provide both position and energy-loss measurements. SIS was especially designed to achieve excellent mass resolution under the extreme, high flux conditions encountered in large solar particle events. It provides a geometry factor of ∼40 cm2 sr, significantly greater than earlier solar particle isotope spectrometers. A microprocessor controls the instrument operation, sorts events into prioritized buffers on the basis of their charge, range, angle of incidence, and quality of trajectory determination, and formats data for readout by the spacecraft. This paper describes the design and operation of SIS and the scientific objectives that the instrument will address. This revised version was published online in June 2006 with corrections to the Cover Date.     

Geostationary tether satellite system and its application tocommunication systems

The geostationary tether satellite system expands the geostationary orbit resource from a one-dimensional arc into a two-dimensional disk. The tethered satellites, each several thousand kilometers apart and aligned along the local vertical, are stabilized at the altitude of the geosynchronous orbital speed. When this system is applied to communications systems, it is estimated that the number of satellites can be increased as much as thirteenfold and the communication capacity can be increased more than seventeenfold, compared with a conventional geostationary satellite orbit system     

The Local Bubble and Interstellar Material Near the Sun

The properties of interstellar matter at the Sun are regulated by our location with respect to a void in the local matter distribution, known as the Local Bubble. The Local Bubble (LB) is bounded by associations of massive stars and fossil supernovae that have disrupted dense interstellar matter (ISM), driving low density intermediate velocity ISM into the void. The Sun appears to be located in one of these flows of low density material. This nearby interstellar matter, dubbed the Local Fluff, has a bulk velocity of ∼19 km s⁻¹ in the local standard of rest. The flow is coming from the direction of the gas and dust ring formed where the Loop I supernova remnant merges into the LB. Optical polarization data suggest that the local interstellar magnetic field lines are draped over the heliosphere. A longstanding discrepancy between the high thermal pressure of plasma filling the LB and low thermal pressures in the embedded Local Fluff cloudlets is partially mitigated when the ram pressure component parallel to the cloudlet flow direction is included.     

Calibration of the MERIC full-polarimetric radar: theory and implementation

This paper describes the architecture and calibration design of the experimental ground based radar station MERIC. This full-polarimetric radar is conceived for the analysis and the recognition of non cooperative aircraft in flight.We carefully study how the full-polarimetric capability is obtained for a simultaneous transmit (simultaneous transmission of two linear FM with opposite slopes) radar system, using analogue deramping with a replica.The phase distortions of the signal propagating in the four polarimetric channels are carefully estimated. We define a phase calibrating method compatible with the outdoor measurements conditions and few constraints on reference targets.We show the phase accuracy obtained with the proposed calibration method on real measurements.     

TMA from bearings and multipath time delays

A novel approach for target motion analysis (TMA), which uses conventional passive bearing together with multipath time-delay measurements is examined. This so-called "Multipath TMA" offers two tactical advantages over the classical bearings-only TMA: no requirement for any ownship maneuver, and a good performance in terms of estimation error achieved in a shorter time. Both known and unknown multipath cases are addressed. Finally, Monte-Carlo simulations and at-sea trials demonstrate the practical efficiency of such a multipath TMA.     

A three-dimensional plasma and energetic particle investigation for the wind spacecraft

This instrument is designed to make measurements of the full three-dimensional distribution of suprathermal electrons and ions from solar wind plasma to low energy cosmic rays, with high sensitivity, wide dynamic range, good energy and angular resolution, and high time resolution. The primary scientific goals are to explore the suprathermal particle population between the solar wind and low energy cosmic rays, to study particle accleration and transport and wave-particle interactions, and to monitor particle input to and output from the Earth's magnetosphere.Three arrays, each consisting of a pair of double-ended semi-conductor telescopes each with two or three closely sandwiched passivated ion implanted silicon detectors, measure electrons and ions above 20 keV. One side of each telescope is covered with a thin foil which absorbs ions below 400 keV, while on the other side the incoming <400 keV electrons are swept away by a magnet so electrons and ions are cleanly separated. Higher energy electrons (up to 1 MeV) and ions (up to 11 MeV) are identified by the two double-ended telescopes which have a third detector. The telescopes provide energy resolution of E/E0.3 and angular resolution of 22.5°×36°, and full 4 steradian coverage in one spin (3 s).Top-hat symmetrical spherical section electrostatic analyzers with microchannel plate detectors are used to measure ions and electrons from 3 eV to 30 keV. All these analyzers have either 180° or 360° fields of view in a plane, E/E0.2, and angular resolution varying from 5.6° (near the ecliptic) to 22.5°. Full 4 steradian coverage can be obtained in one-half or one spin. A large and a small geometric factor analyzer measure ions over the wide flux range from quiet-time suprathermal levels to intense solar wind fluxes. Similarly two analyzers are used to cover the wide range of electron fluxes. Moments of the electron and ion distributions are computed on board.In addition, a Fast Particle Correlator combines electron data from the high sensitivity electron analyzer with plasma wave data from the WAVE experiment (Bougeretet al., in this volume) to study wave-particle interactions on fast time scales. The large geometric factor electron analyzer has electrostatic deflectors to steer the field of view and follow the magnetic field to enhance the correlation measurements.     

Clinorotation reduces number, but not size, of cartilaginous nodules formed in micromass cultures of mouse limbbud cells.

In previous studies we used a ground based model to investigate the cellular responses to microgravity by exposing micromass cultures of embryonic limb cells to simulated weightlessness on a clinostat. Cultures set up in T-flasks and rotated at 30 rpm showed that clinostatted cultures had less chondrocyte differentiation than stationary or rotation controls, as assessed by number of nodules/culture stained with cartilage specific Alcian blue. In the current study, nodule size and shape of these nodules was assessed by interactive measurement of area, perimeter, circularity, and equivalent diameters, using the Optimas imaging software. Results show no significant difference in any of the measurements, indicating that clinorotation has no effect on expansion of the nodules either by differentiation of cells within the nodule, or by recruitment of cells into the nodule. The reduction in number of nodules without an alteration in size and shape indicates that the effect of simulated microgravity is to reduce the cell interactions required for the initial condensation of cells into a nodule, probably by interference with cell adhesion molecules.