RUSHMAPS: Real-Time Uploadable Spherical Harmonic Moment Analysis for Particle Spectrometers

RUSHMAPS is a new onboard data reduction scheme that gives real-time access to key science parameters (e.g. moments) of a class of heliophysics science and/or solar system exploration investigation that includes plasma particle spectrometers (PPS), but requires moments reporting (density, bulk-velocity, temperature, pressure, etc.) of higher-level quality, and tolerates a lowpass (variable quality) spectral representation of the corresponding particle velocity distributions, such that telemetry use is minimized. The proposed methodology trades access to the full-resolution velocity distribution data, saving on telemetry, for real-time access to both the moments and an adjustable-quality (increasing quality increases volume) spectral representation of distribution functions. Traditional onboard data storage and downlink bandwidth constraints severely limit PPS system functionality and drive cost, which, as a consequence, drives a limited data collection and lower angular energy and time resolution. This prototypical system exploit, using high-performance processing technology at GSFC (Goddard Space Flight Center), uses a SpaceCube and/or Maestro-type platform for processing. These processing platforms are currently being used on the International Space Station as a technology demonstration, and work is currently ongoing in a new onboard computation system for the Earth Science missions, but they have never been implemented in heliospheric science or solar system exploration missions. Preliminary analysis confirms that the targeted processor platforms possess the processing resources required for realtime application of these algorithms to the spectrometer data. SpaceCube platforms demonstrate that the target architecture possesses the sort of compact, low-mass/power, radiation-tolerant characteristics needed for flight. These high-performing hybrid systems embed unprecedented amounts of onboard processing power in the CPU (central processing unit), FPGAs (field programmable gate arrays), and DSP (digital signal processing) elements. The fundamental computational algorithm de constructs 3D velocity distributions in terms of spherical harmonic spectral coefficients (which are analogous to a Fourier sine-cosine decomposition), but uses instead spherical harmonics Legendre polynomial orthogonal functions as a basis for the expansion, portraying each 2D angular distribution at every energy or, geometrically, spherical speed-shell swept by the particle spectrometer. Optionally, these spherical harmonic spectral coefficients may be telemetered to the ground. These will provide a smoothed description of the velocity distribution function whose quality will depend on the number of coefficients determined. Successfully implemented on the GSFC-developed processor, the capability to integrate the proposed methodology with both heritage and anticipated future plasma particle spectrometer designs is demonstrated (with sufficiently detailed design analysis to advance TRL) to show specific science relevancy with future HSD (Heliophysics Science Division) solar-interplanetary, planetary missions, sounding rockets and/or CubeSat missions

Powered Descent Guidance with General Thrust-Pointing Constraints

The Powered Descent Guidance (PDG) algorithm and software for generating Mars pinpoint or precision landing guidance profiles has been enhanced to incorporate thrust-pointing constraints. Pointing constraints would typically be needed for onboard sensor and navigation systems that have specific field-of-view requirements to generate valid ground proximity and terrain-relative state measurements. The original PDG algorithm was designed to enforce both control and state constraints, including maximum and minimum thrust bounds, avoidance of the ground or descent within a glide slope cone, and maximum speed limits. The thrust-bound and thrust-pointing constraints within PDG are non-convex, which in general requires nonlinear optimization methods to generate solutions. The short duration of Mars powered descent requires guaranteed PDG convergence to a solution within a finite time; however, nonlinear optimization methods have no guarantees of convergence to the global optimal or convergence within finite computation time. A lossless convexification developed for the original PDG algorithm relaxed the non-convex thrust bound constraints. This relaxation was theoretically proven to provide valid and optimal solutions for the original, non-convex problem within a convex framework. As with the thrust bound constraint, a relaxation of the thrust-pointing constraint also provides a lossless convexification that ensures the enhanced relaxed PDG algorithm remains convex and retains validity for the original nonconvex problem. The enhanced PDG algorithm provides guidance profiles for pinpoint and precision landing that minimize fuel usage, minimize landing error to the target, and ensure satisfaction of all position and control constraints, including thrust bounds and now thrust-pointing constraints

X-Ray Detection and Processing Models for Spacecraft Navigation and Timing

The current primary method of deepspace navigation is the NASA Deep Space Network (DSN). High-performance navigation is achieved using Delta Differential One-Way Range techniques that utilize simultaneous observations from multiple DSN sites, and incorporate observations of quasars near the line-of-sight to a spacecraft in order to improve the range and angle measurement accuracies. Over the past four decades, x-ray astronomers have identified a number of xray pulsars with pulsed emissions having stabilities comparable to atomic clocks. The x-ray pulsar-based navigation and time determination (XNAV) system uses phase measurements from these sources to establish autonomously the position of the detector, and thus the spacecraft, relative to a known reference frame, much as the Global Positioning System (GPS) uses phase measurements from radio signals from several satellites to establish the position of the user relative to an Earth-centered fixed frame of reference. While a GPS receiver uses an antenna to detect the radio signals, XNAV uses a detector array to capture the individual xray photons from the x-ray pulsars. The navigation solution relies on detailed xray source models, signal processing, navigation and timing algorithms, and analytical tools that form the basis of an autonomous XNAV system. Through previous XNAV development efforts, some techniques have been established to utilize a pulsar pulse time-of-arrival (TOA) measurement to correct a position estimate. One well-studied approach, based upon Kalman filter methods, optimally adjusts a dynamic orbit propagation solution based upon the offset in measured and predicted pulse TOA. In this delta position estimator scheme, previously estimated values of spacecraft position and velocity are utilized from an onboard orbit propagator. Using these estimated values, the detected arrival times at the spacecraft of pulses from a pulsar are compared to the predicted arrival times defined by the pulsar s pulse timing model. A discrepancy provides an estimate of the spacecraft position offset, since an error in position will relate to the measured time offset of a pulse along the line of sight to the pulsar. XNAV researchers have been developing additional enhanced approaches to process the photon TOAs to arrive at an estimate of spacecraft position, including those using maximum-likelihood estimation, digital phase locked loops, and "single photon processing" schemes that utilize all available time data associated with each photon. Using pulsars from separate, non-coplanar locations provides range and range-rate measurements in each pulsar s direction. Combining these different pulsar measurements solves for offsets in position and velocity in three dimensions, and provides accurate overall navigation for deep space vehicles

Reciprocidad y amistad.

Sin resume

Other voices: Argentine narrative during the military process (1976-83)

Dissertation (Ph.D.)--University of Kansas, Spanish and Portuguese, 1998

Communicating COVID-19: Metaphors We “Survive” By

El objetivo de este trabajo es describir el marco de la pandemia que el mundo soporta actualmente durante la cuarentena obligatoria que tiene lugar en Argentina. Este estudio en particular es parte de un corpus de investigación más grande que investiga la relación entre discursos sostenidos por empresas, políticos y medios en la era digital y cómo afecta la comunicación en tiempos de crisis. Este es un estudio cualitativo que explora el lenguaje metafórico emergente que se está implementando para comunicar aspectos sobresalientes del fenómeno sin precedentes que es COVID-19 de manera parcial. Es importante señalar que el análisis se realiza al mismo tiempo que se desarrolla la crisis. Para desarrollar esta perspectiva, nos basaremos en un marco previo desarrollado para estudiar la comunicación de crisis. Nuestra investigación nos ha llevado a identificar una "familia" de metáforas que emergen de los titulares del corpus: guerra, cuidado y tiempo. Identificar y comprender las metáforas emergentes es el primer paso para evitar contradicciones que pueden conducir a enlaces dobles.The objective of this paper is to describe the framing of the pandemic that the world currently endures during the mandatory quarantine taking place in Argentina. This particular study is part of a bigger corpus of research that investigates the relationship between discourses held by enterprises, politicians and media in the digital age and how it affects communication at times of crisis. This is a qualitative study that explores emerging metaphorical language that is being implemented to communicate salient aspects of the unprecedented phenomenon that is COVID-19 in a partial way. It is important to point out that the analysis is made at the same time that the crisis is unfolding. In order to develop this perspective, we will rely on a previous framework developed to study communication of crisis. Our research has led us to identify a “family” of metaphors that emerge from the headlines of the corpus: war, care and time. Identifying and understanding the emerging metaphors is the first step to avoid contradictions that can lead to double binds.Fil: Fernandez Pedemonte, Damian Manuel. Universidad Austral. Facultad de Comunicación. Dirección de Posgrado; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Casillo, Felicitas Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Austral. Facultad de Comunicación. Dirección de Posgrado; ArgentinaFil: Jorge Artigau, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Austral. Facultad de Comunicación. Dirección de Posgrado; Argentin

La mirada filosófica: un vistazo al rostro del otro

La filosofía tiene aún vigencia. Sin embargo, esa vigencia, su rol particu-lar respecto de las condiciones sociales en las que nos encontramos, dis-ta de ser clara y evidente. Por eso es necesaria una reconceptualización de la filosofía que capture su verdadera esencia transformadora. De la mano de diferentes autores, pertenecientes a diferentes escuelas de pensamiento filosófico, se produce aquí una reflexión en torno a los problemas pertinentes para la filosofía, vista desde su capacidad de incidir decisivamente en transformar el contexto social actual. En primer lugar, se contraponen dos visiones de la práctica, como objetos de refle-xión filosófica tal cual fueran formulados por Carlos Marx: la poiesis y la praxis. Luego de rescatar para la praxis el carácter moral, se especifican las condiciones originarias de la praxis moral, analizada desde la pers-pectiva de Emmanuel Levinas, Zygmunt Bauman y Enrique Dussel. Fi-nalmente, se propone una visión de la filosofía que la inserta en el pro-ceso de transformación política y moral de la sociedad: la filosofía debe propiciar un cambio en la mirada hacia el rostro de los otros

Altas y bajas: las defensas en democracia

El 10 de diciembre de 1983, Raúl Alfonsín también asumía como comandante en jefe de las FFAA, un cargo que por más de 50 años constituyó enredos, condicionamientos y derrocamientos. El enfrentamiento del tema militar junto al peso opresivo de la deuda externa, fueron las dos tensiones más densas que en herencia recibía de la dictadura la incipiente democracia, nacida de la derrota nacional de la guerra de Malvinas y del repudio creciente a su política impopular y represiva.Dossier: 30 años de democraciaFacultad de Periodismo y Comunicación Socia