Electrical/​Electronics

High-speed complex-amplitude spatial light modulators (SLMs) containing liquid crystals with pixel electronic circuitry on single-crystal-silicon backplanes are undergoing development. The basic approach taken in this project is to use fast-switching liquid-crystal materials and modulation-enhancing...

A laser illuminator system has been developed for use in automated tracking of objects. In its original application, the system illuminates a 5° conical region expected to contain a small satellite at a distance up to 750 m from the space shuttle. If the satellite comes within this region, then a receiving...

An integrated optical voltage-measuring apparatus based on a Mach-Zehnder interferometer has been designed and constructed. The main feature of this apparatus is that optical fibers link part of it to an optical sensor head placed at the source of the voltage to be measured, whether the source be a...

An apparatus records triaxial acceleration and temperature as a function of time, operating unattended for as long as 3 weeks on power supplied by two D cells. The apparatus, which has dimensions of only 3.5 by 4.5 by 2.2 in. (8.9 by 11.4 by 5.6 cm) and weighs only 28.5 oz (0.81 kg) is designed...

A dynamic random-access memory (DRAM) circuit that tolerates single-event upsets (SEUs) has been developed. A single-event upset is a bit flip caused by ionizing radiation. In a DRAM, the state of each bit (0 or 1) is stored as charge on a buried capacitor. The impingement of an energetic charged particle...

Lightweight reflector dishes for radio antennas would be mass-produced cheaply by spin casting of polymers, according to a proposal. These reflector dishes were conceived for compact stowage followed by deployment and operation aboard spacecraft, but might also be useful on Earth in...

A retroreflective communication system (RCS), is a state-of-the-art system that provides (1) two-way optical communication using only one transmitter and (2) multipath communication among remote locations. RCSs were conceived for use in communication among stations on the ground and aboard spacecraft in...

An algorithm for filtering synthetic-aperture-radar (SAR) interferograms has been developed which substantially improves the performance of subsequent phase-unwrapping. It accomplishes this task by filtering the interferogram strongly in areas where the scene contains little detail, and weakly where the...

The forward-link/simulator card (FLS) performs the fundamental satellite-telemetry data-transmission function for the forward (Earth-to-spacecraft) link in real time at rates up to 400 Mb/s. The FLS also simulates a Consultative Committee for Space Data Systems (CCSDS) telemetry data source that outputs data at rates...

Two reports present further developments in the subject of "Computation of Characteristics of a Helical TWT Slow-Wave Circuit" (LEW-16571), NASA Tech Briefs, Vol. 22, No. 4 (April 1998), page 54. The subject is computation, by use of the MAFIA (Solution of MAxwell's Equations by the...