Study and applications of retrodirective and self adaptive electromagnetic-wave phase controls to a Mars probe

Computer analyses of retrodirective, and self adaptive antenna phase control techniques for Mars prob

Discrete Impedance Metasurfaces for 6G Wireless Communications in D-Band

Engineering and optimization of wireless propagation channels will be one of the key elements of future communication technologies. Metasurfaces may offer a wide spectrum of functionalities for passive and tunable reflecting devices, overcoming fundamental limits of commonly used conventional phase-gradient reflectarrays and metasurfaces. In this paper, we develop an efficient way for the design and implementation of metasurfaces with high-efficiency anomalous reflector functionalities. The developed numerical method provides accurate, fast, and simple metasurface designs, taking into account non-local near-field interactions between array elements. The design method is validated by manufacturing and experimental testing of highly efficient anomalous reflectors for the millimetre-wave band.Comment: 8 pages, 8 figure

2020 NASA Technology Taxonomy

This document is an update (new photos used) of the PDF version of the 2020 NASA Technology Taxonomy that will be available to download on the OCT Public Website. The updated 2020 NASA Technology Taxonomy, or "technology dictionary", uses a technology discipline based approach that realigns like-technologies independent of their application within the NASA mission portfolio. This tool is meant to serve as a common technology discipline-based communication tool across the agency and with its partners in other government agencies, academia, industry, and across the world

Survey of Inter-satellite Communication for Small Satellite Systems: Physical Layer to Network Layer View

Small satellite systems enable whole new class of missions for navigation, communications, remote sensing and scientific research for both civilian and military purposes. As individual spacecraft are limited by the size, mass and power constraints, mass-produced small satellites in large constellations or clusters could be useful in many science missions such as gravity mapping, tracking of forest fires, finding water resources, etc. Constellation of satellites provide improved spatial and temporal resolution of the target. Small satellite constellations contribute innovative applications by replacing a single asset with several very capable spacecraft which opens the door to new applications. With increasing levels of autonomy, there will be a need for remote communication networks to enable communication between spacecraft. These space based networks will need to configure and maintain dynamic routes, manage intermediate nodes, and reconfigure themselves to achieve mission objectives. Hence, inter-satellite communication is a key aspect when satellites fly in formation. In this paper, we present the various researches being conducted in the small satellite community for implementing inter-satellite communications based on the Open System Interconnection (OSI) model. This paper also reviews the various design parameters applicable to the first three layers of the OSI model, i.e., physical, data link and network layer. Based on the survey, we also present a comprehensive list of design parameters useful for achieving inter-satellite communications for multiple small satellite missions. Specific topics include proposed solutions for some of the challenges faced by small satellite systems, enabling operations using a network of small satellites, and some examples of small satellite missions involving formation flying aspects.Comment: 51 pages, 21 Figures, 11 Tables, accepted in IEEE Communications Surveys and Tutorial

A Novel Retro-directive Phased Array Antenna Architecture

Mobile wireless communication scenarios can range from a simple indoor WiFi link to a satellite internet connection to an airplane. Virtually in all scenarios, dynamic changes in the propagation environment or the movement of transmitter and receiver are inevitable. Therefore, the wireless link often experiences quality degradation or even interruption. Adaptive antenna arrays offer a promising solution to combat wireless channel impairments as they adaptively reshape their radiation pattern. For two-way communication, an antenna should be retro-directive meaning its transmit and receive beams are aligned. To achieve retro-directivity, techniques based on direction-of-arrival and self-phasing can be used. The former usually calls for a complex calibration routine to estimate the direction of arrival and beamsteering; the latter relies on the received signal to generate the transmit beam, imposing several limitations on its adaptability. In this thesis, a novel retro-directive phased array architecture is proposed that does not require calibration and which generates its transmit wave independently of its receive wave. Moreover, its radiation pattern can be adaptively shaped by a simple beamforming algorithm, while its transmitted and received beams remain aligned. Structurally, it is comprised of independent modules that can be placed in virtually any arrangement without any hardware modification. The architecture uses the LO phase-shifting technique to steer its beams. The LO signals are generated with a novel frequency synthesizer; it creates a pair of LO signals for the transmission and reception paths to achieve retro-directivity. The proposed antenna architecture is demonstrated practically using a 10-element prototype, verifying its ability to steer the transmit and receive beams while keeping them aligned. In addition, two of the key circuit components of the LO synthesizer, a fractional frequency divider and a novel phase-conjugating phase shifter, are designed and successfully implemented on 65nm CMOS technology, paving the path for use in future applications

Technology for large space systems: A special bibliography with indexes (supplement 05)

This bibliography lists 298 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1981 and June 30, 1981. Its purpose is to provide helpful, information to the researcher, manager, and designer in technology development and mission design in the area of the Large Space Systems Technology (LSST) Program. Subject matter is grouped according to systems, interactive analysis and design, structural concepts, control systems, electronics, advanced materials, assembly concepts, propulsion, solar power satellite systems, and flight experiments