SEARCH · Search NASA
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Spaceborne remote sensing instruments allow the acquisition of global and synoptic information for Earth Science investigations. In particular, active microwave remote sensing that have contributed geophysical measurements of a scale and accuracy which surpass what could be accomplished with ariborne or in-situ observations.
Modern spaceborne radar scatterometers such as the NASA Scatterometer (NSCAT) and SeaWinds radar instruments require precise determination of the normalized backscattered radar cross section within a few tenth of a decibel in order to achieve the desired wind velocity and direction measurement accuracy of 2 m/s and 20 degrees respectively.
A set of space environmental test specifications has been defined for spaceborne computer modules and is identified in IEEE P1156.4,.
The OH radical is an important player in known ozone depletion cycles; however, due to its location in the atmosphere, it must be studied from either a balloon or spaceborne platform.
We present a real-time high-performance and fault-tolerant FPGA-based hardware architecture for the processing of synthetic aperture radar (SAR) images in future spaceborne system. In particular, we will discuss the integrated design approach, from top-level algorithm specifications and system requirements, design methodology, functional verification and performance validation, down to hardware design and implementation.
This document presents an interference mitigation technique using the active spaceborne sensor SAR3 antenna in the Earth Exploration-Satellite Service (active) and Space Research Service (active) for use in a 500 MHz bandwidth near 9.6 GHz. The purpose of the document is present antenna designs which offer lower sidelobes and faster rolloff in the sidelobes which in turn mitigates the interference to other services from the EESS (active) and SRS (active) sensors.
This document presents a study of out of band (OOB) 40 dB bandwidth requirements of spaceborne SARs in the Earth Exploration-Satellite Service (active) and Space Research Service (active). The purpose of the document is to study the OOB 40 dB bandwidth requirements and compare the 40 dB bandwidth B-40 as measured in simulations with that calculated using the ITU-R Rec SM.1541 equations. The spectra roll-off and resulting OOB 40 dB bandwidth of the linear FM signal is affected by the time-bandwidth product and the rise/fall times. Typical values of these waveform characteristics are given for existing EESS (active) sensors.
The Spaceborne Imaging Radar-C / X-band Synthetic Aperture Radar (SIR-C/X-SAR, the most advanced imaging radar system to have flown in Earth orbit, was carried in the cargo bay of the Space Shuttle Endeavour in April and October, 1994. SIR-C/X-SAR simultaneously recorded data at three wavelengths (L-, C-, and X-bands; 23.5, 5.8 and 3.1 cm respectively).
This paper describes the Micro-Precision Interferometer (MPI) testbed and its major achievements to date related to mitigating risk for future spaceborne optical interferometer missions.
This paper proposes a vibration attenuation strategy for spaceborne optical interferometers to meet their sub-micron positional stability requirements.
Reliable miniature spaceborne memory system design, and testing of breadboard version of circuits and memory plane
Design and testing of majority logic redundancy for spaceborne and GSE digital systems
On board computer simultaneously processing spaceborne data including life support, energy management, human performance control, etc
Electronically-scanned K-band passive phased array for spaceborne radiometry
Multiprocessor organization, integrated circuit techniques, self-repairing systems for spaceborne computer designs - conference
Active optical system for spaceborne, orbiting telescopes
Bibliography and new techniques for use of error correction and redundancy to improve reliability of spaceborne computers
Spaceborne memory organization, associative data acquisition system design, and data compression techniques