Physical Sciences

Cryogenic Liquid Sample Acquisition System for Remote Space Applications

There is a need to acquire autonomously cryogenic hydrocarbon liquid sample from remote planetary locations such as the lakes of Titan for instruments such as mass spectrometers. There are several problems that had to be solved relative to collecting the right amount of cryogenic liquid sample into a warmer spacecraft, such as not allowing the sample to boil off or fractionate too early; controlling the intermediate and final pressures within carefully designed volumes; designing for various particulates and viscosities; designing to thermal, mass, and power-limited spacecraft interfaces; and reducing risk. Prior art inlets for similar instruments in spaceflight were designed primarily for atmospheric gas sampling and are not useful for this front-end application.

Posted in: Briefs, TSP, Physical Sciences, Data Acquisition, Hydrocarbons, Test equipment and instrumentation, Test procedures, Spacecraft

Integrating a Microwave Radiometer into Radar Hardware for Simultaneous Data Collection Between the Instruments

Electronics are shared between the instruments.

The conventional method for integrating a radiometer into radar hardware is to share the RF front end between the instruments, and to have separate IF receivers that take data at separate times. Alternatively, the radar and radiometer could share the antenna through the use of a diplexer, but have completely independent receivers. This novel method shares the radar’s RF electronics and digital receiver with t he radiometer, while allowing for simultaneous operation of the ra da r and radiometer.

Posted in: Briefs, TSP, Physical Sciences, Data Acquisition, Antennas, Data acquisition and handling, Radar, Radio equipment, Antennas, Data acquisition and handling, Radar, Radio equipment

High-Speed Data Recorder for Space, Geodesy, and Other High-Speed Recording Applications

A high-speed data recorder and replay equipment has been developed for reliable high-data-rate recording to disk media. It solves problems with slow or faulty disks, multiple disk insertions, high-altitude operation, reliable performance using COTS hardware, and long-term maintenance and upgrade path challenges.

Posted in: Briefs, Physical Sciences, Data Acquisition, Computer software / hardware, Computer software and hardware, Computer software / hardware, Computer software and hardware, Data management, Storage, Event data recorders

A Short-Range Distance Sensor with Exceptional Linearity

Potential uses exist in the areas of micromachining and nanotechnology.

A sensor has been demonstrated that can measure distance over a total range of about 300 microns to an accuracy of about 0.1 nm (resolution of about 0.01 nm). This represents an exceptionally large dynamic range of operation — over 1,000,000. The sensor is optical in nature, and requires the attachment of a mirror to the object whose distance is being measured.

Posted in: Briefs, Physical Sciences, Measurements, Optics, Sensors and actuators, Optics, Sensors and actuators

Fast, Large-Area, Wide-Bandgap UV Photodetector for Cherenkov Light Detection

This detector can be used for monitoring fires, microbial sterilization/disinfection processing, and spectrophotometry analysis.

Due to limited resources available for power and space for payloads, miniaturizing and integrating instrumentation is a high priority for addressing the challenges of manned and unmanned deep space missions to high Earth orbit (HEO), near Earth objects (NEOs), Lunar and Martian orbits and surfaces, and outer planetary systems, as well as improvements to high-altitude aircraft safety. New, robust, and compact detectors allow future instrumentation packages more options in satisfying specific mission goals.

Posted in: Briefs, TSP, Physical Sciences, Downsizing, Semiconductors, Test equipment and instrumentation, Spacecraft

Miniature Trace Gas Detector Based on Microfabricated Optical Resonators

Ultra-sensitive detection of molecules is available with a modified whispering gallery mode resonator.

While a variety of techniques exist to monitor trace gases, methods relying on absorption of laser light are the most commonly used in terrestrial applications. Cavity-enhanced absorption techniques typically use high-reflectivity mirrors to form a resonant cavity, inside of which a sample gas can be analyzed. The effective absorption length is augmented by the cavity’s high quality factor, or Q, because the light reflects many times between the mirrors. The sensitivity of such mirrorbased sensors scales with size, generally making them somewhat bulky in volume. Also, specialized coatings for the high-reflectivity mirrors have limited bandwidth (typically just a few nanometers), and the delicate mirror surfaces can easily be degraded by dust or chemical films.

Posted in: Briefs, TSP, Physical Sciences, Optics, Sensors and actuators, Optics, Sensors and actuators, Gases

Enhancing Microwave Spectroscopy in Astrophysics Applications

An arbitrary waveform generator is the key element in this faster and more accurate method.

In popular perception, the vastness of space is an empty vacuum dotted with stars, planets, black holes, and other celestial formations. In reality, astrophysicists have shown that space contains low-density matter — gas clouds, dust grains, and more — existing in ionic, atomic, or molecular phases.

Posted in: Briefs, Physical Sciences, Antennas, Spectroscopy, Antennas, Spectroscopy, Chemicals, Gases

JWST Integrated Science Instrument Module Alignment Optimization Tool

During cryogenic vacuum testing of the James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM), the global alignment of the ISIM with respect to the designed interface of the JWST optical telescope element (OTE) will be measured through a series of optical characterization tests. These tests will determine the locations and orientations of the JWST science instrument projected focal surfaces and entrance pupils with respect to their corresponding OTE optical interfaces. If any optical performance non-compliances are identified, the ISIM will be adjusted to improve its performance. In order to understand how to manipulate the ISIM’s degrees of freedom properly and to prepare for the ISIM flight model testing, a series of opticalmechanical analyses have been completed to develop and identify the best approaches for bringing a non-compliant ISIM element into compliance.

Posted in: Briefs, TSP, Physical Sciences, Optics, Optics, Performance tests, Test procedures

Radar Range Sidelobe Reduction Using Adaptive Pulse Compression Technique

There is significant improvement on sidelobe performance.

Pulse compression has been widely used in radars so that low-power, long RF pulses can be transmitted, rather than a high-power short pulse. Pulse compression radars offer a number of advantages over high-power short pulsed radars, such as no need of highpower RF circuitry, no need of high-voltage electronics, compact size and light weight, better range resolution, and better reliability. However, range sidelobe associated with pulse compression has prevented the use of this technique on spaceborne radars since surface returns detected by range sidelobes may mask the returns from a nearby weak cloud or precipitation particles. Research on adaptive pulse compression was carried out utilizing a field-programmable gate array (FPGA) waveform generation board and a radar transceiver simulator. The results have shown significant improvements in pulse compression sidelobe performance.

Posted in: Briefs, TSP, Physical Sciences, Radar, Radar, Research and development, Spacecraft

Digitally Calibrated TR Modules Enabling Real-Time Beamforming SweepSAR Architectures

Civilian and military remote sensing instruments could benefit from this work, as well as military intelligence applications.

SweepSAR, a novel radar architecture that depends on a DBF (digital beamforming) array, requires calibration accuracies that are order(s) of magnitude greater than is possible with traditional techniques, such as a priori characterization of TR (transmit/receive) modules in thermal vacuum chambers, or simple loop-back of the calibration signal. The advantages of a SweepSAR architecture are so great that it is worth applying significant resources to calibration efforts.

Posted in: Briefs, TSP, Physical Sciences, Calibration, Architecture, Radar, Architecture, Radar

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