Metadata Updated: February 28, 2019

The goal of this project is to develop the Ocean-salinity Soil-moisture Integrated Radiometer-radar Imaging System (OSIRIS) instrument concept for combined passive and active sensing in the 1-3GHz range, using a 6m diameter, lightweight, deployable mesh antenna. The OSIRIS concept was used as the starting point to determine specifications and error budgets for the instrument subsystems and to evaluate the science performance. Key technology issues were then identified to scope the study. The ability of a tensioned wire mesh to serve as a high- precision, high reflectivity and low emissivity antenna reflector surface at low frequencies is a key requirement. The emissivity must be low enough that uncertainties in the emissivity and physical temperature of the reflecting surface do not give rise to excessive thermal noise. The design of the reflector and feedhorns, and the surface shape accuracy of the reflector, must provide antenna patterns that meet the required performance for beam efficiency, gain, sidelobe levels, and cross-polarization. Mass and power requirements must be kept to a minimum, and the rotational dynamics of the antenna and the attitude control requirements and capabilities of the spacecraft must be well understood. The volume of the combined antenna and spacecraft in the stowed configuration and the total mass must be within the capabilities of a low-cost launch vehicle. To address these issues, the specific objectives of the study were outlined as follows:(1) Perform a requirements analysis to validate the baseline instrument design (measurement channels, sensitivities, beam-pointing, sampling, and other system and orbital characteristics) and to assess the geophysical retrieval accuracies and allowable error budgets for the instrument subsystems[HTML_REMOVED](2) [HTML_REMOVED]Perform laboratory measurements of wire mesh samples to determine their microwave emissivity, and evaluate the ability of mesh reflectors to meet the required brightness temperature precision and calibration stability(3) [HTML_REMOVED]Design lightweight, multifrequency, dual-polarized feedhorns and electronics subsystems, including passive and active channels at L- and S-band frequencies, for a rotating parabolic mesh reflector system, and analyze the antenna pattern characteristics and performance(4) [HTML_REMOVED]Perform an antenna and spacecraft configuration, integration, and optimization study, including deployment mechanisms, mechanical and thermal modeling, and attitude control analysis of the antenna and spacecraft system.[HTML_REMOVED]

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Public: This dataset is intended for public access and use. License: U.S. Government Work

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Metadata Created Date August 1, 2018
Metadata Updated Date February 28, 2019

Metadata Source

Harvested from NASA Data.json

Additional Metadata

Resource Type Dataset
Metadata Created Date August 1, 2018
Metadata Updated Date February 28, 2019
Publisher Space Technology Mission Directorate
Unique Identifier TECHPORT_33098
Maintainer Email
Public Access Level public
Bureau Code 026:00
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Harvest Object Id 7e496dd1-7aa5-44c4-9d2f-c97c1bacc5f6
Harvest Source Id 39e4ad2a-47ca-4507-8258-852babd0fd99
Harvest Source Title NASA Data.json
Data First Published 2002-08-01
Homepage URL
Data Last Modified 2018-07-19
Program Code 026:027
Source Datajson Identifier True
Source Hash f20dee316b2a4d6aad5dfde010dbc1dc66a52f9d
Source Schema Version 1.1

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