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NASA Technology Provides Secure Networks for First Responders

In 2003, engineers at NASA’s Glenn Research Center in Cleveland, OH, sent a miniature Cisco router into low Earth orbit on a satellite, proving that Internet Protocols can be used to communicate with satellites. “We wanted to put the Internet in space because it will make it far easier to design, build, test, and later operate new satellite systems,” said Phil Paulsen, project manager in Glenn’s Space Communications Office.

Posted in: UpFront

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NASA Spinoff Brings Nanotechnology to Market

NASA’s Goddard Space Flight Center in Greenbelt, MD, licensed its patented technique for manufacturing high-quality, single-walled carbon nanotubes (CNTs) to Idaho Space Materials (ISM) in Boise. Carbon nanotubes based on this process are being used by researchers and companies working on the next generation of composite polymers, metals, and ceramics that will impact almost every facet of life.

Posted in: UpFront

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Bare Conductive Tether for Decelerating a Spacecraft

A document describes a prototype of electrically conductive tethers to be used primarily to decelerate spacecraft and/or generate electric power for the spacecraft. Like prior such tethers, this tether is designed so that when it is deployed from a spacecraft in orbit, its motion across the terrestrial magnetic field induces an electric current. The Lorentz force on the current decelerates the spacecraft. Optionally, the current can be exploited to convert some orbital kinetic energy to electric energy for spacecraft systems. Whereas the conductive portions of prior such tethers are covered with electrical insulation except for end electrodes that make contact with the ionosphere, this tether includes a conductive portion that is insulated along part of its length but deliberately left bare along a substantial remaining portion of its length to make contact with the ionosphere. The conductive portions of the tether are made of coated thin aluminum wires wrapped around strong, lightweight aromatic polyamide braids. The main advantages of the present partly-bare-tether design over the prior all-insulated-tether design include greater resistance to degradation by the impact of monatomic oxygen at orbital altitude and speed and greater efficiency in collecting electrons from the ionosphere.

Posted in: Briefs, TSP

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Staggering Inflation To Stabilize Attitude of a Solar Sail

A document presents computational simulation studies of a concept for stabilizing the attitude of a spacecraft during deployment of such structures as a solar sail or other structures supported by inflatable booms. Specifically, the solar sail considered in this paper is a square sail with inflatable booms and attitude control vanes at the corners. The sail inflates from its stowed configuration into a square sail with four segments and four vanes at the tips. Basically, the concept is one of controlling the rates of inflation of the booms to utilize in mass distribution properties to effect changes in the system’s angular momentum.

Posted in: Briefs, TSP

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Arrays of Bundles of Carbon Nanotubes as Field Emitters

Area-averaged current densities exceed those of arrays of single nanotubes. Experiments have shown that with suitable choices of critical dimensions, planar arrays of bundles of carbon nanotubes (see figure) can serve as high-current-density field emitter (cold-cathode) electron sources. Whereas some hot-cathode electron sources must be operated at supply potentials of thousands of volts, these cold-cathode sources generate comparable current densities when operated at tens of volts. Consequently, arrays of bundles of carbon nanotubes might prove useful as cold-cathode sources in miniature, lightweight electron-beam devices (e.g., nanoklystrons) soon to be developed.

Posted in: Briefs, TSP

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Delta-Doped CCDs as Detector Arrays in Mass Spectrometers

Improved performance is obtained with reduced size, mass, and power. Delta-doped, back-illuminated charge-coupled devices (CCDs) are used as detector arrays in high-performance double- focusing miniature mass spectrometers of Mattauch-Herzog design (described below). The uses of delta-doped CCD detector arrays eliminates the need for microchannel plates (MCPs) and the high-voltage power supplies, that, heretofore, have been used in detection schemes in mass spectrometers; this makes it possible to reduce the sizes, masses, and power demands of mass spectrometers. The use of delta-doped CCDs enables the direct and simultaneous measurement of ions with different masses separated along the focal plane.

Posted in: Briefs, TSP

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Array of Bolometers for Submillimeter-Wavelength Operation

This is a prototype of arrays for astrophysical imaging and photometry. A feed-horn-coupled monolithic array of micromesh bolometers is undergoing development for use in a photometric camera. The array is designed for conducting astrophysical observations in a wavelength band centered at 350 μm. The bolometers are improved versions of previously developed bolometers comprising metalized Si3N4 micromesh radiation absorbers coupled with neutron-transmutation-doped Ge thermistors. Incident radiation heats the absorbers above a base temperature, changing the electrical resistance of each thermistor. In the present array of improved bolometers (see figure), the thermistors are attached to the micromesh absorbers by indium bump bonds and are addressed by use of lithographed, vapor-deposited electrical leads. This architecture reduces the heat capacity and minimizes the thermal conductivity to 1/20 and 1/300, respectively, of earlier versions of these detectors, with consequent improvement in sensitivity and speed of response.

Posted in: Briefs, TSP

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