Special Coverage

Home

Multiplexer for Multiple Sensors in a Vacuum Chamber

The multiplexer reduces the number of required feedthroughs and ports. John F. Kennedy Space Center, Florida Vacuum chamber testing at large facilities can require hundreds of instruments, necessitating even more feedthroughs. The number of instruments and sensors that can be fed into a vacuum chamber is limited by the number of feedthrough ports dedicated to instrumentation. Thus high-pin-count, mil-spec-style feedthroughs have been developed, but these are all custom-made and also expensive to make and replace. The high-pin-count feedthroughs also make it much harder to troubleshoot individual wires in case of a problem. By using a multiplexer within the vacuum chamber, the number of wires required per instrument can be reduced to much less than one. The multiplication of wires from within a vacuum chamber allows a drastic increase in sensor and instrumentation channel count, while using the same number of sensor ports and feedthroughs within an existing vacuum system.

Posted in: Physical Sciences, Sensors, Briefs, TSP

Read More >>

Analog Ceramic Isolated Voltage Sensor

John H. Glenn Research Center, Cleveland, Ohio Galvanic isolated monitoring of voltages for launch vehicle, missiles, and space-deployed systems can be very challenging. Radiation exposure makes use of optics-based sensors difficult, as they can latch-up and become corrupted by the radiation environment; such devices can moreover be thermally challenged. Magnetic transformer-based methods of isolated voltage measurement require shielding to prevent stray magnetic interference from degrading or corrupting the readings; moreover, magnetic-based solutions are unable to measure voltages down to DC levels.

Posted in: Physical Sciences, Sensors, Briefs, TSP

Read More >>

Flexible and Erectable Magnetic Field Response Sensors

Langley Research Center, Hampton, Virginia The means to make a flexible and/or erectable magnetic field response sensor, a geometrically fixed capacitor mounting frame, a wireless dipstick, and an elastically flexible capacitor support have been developed. Either the capacitor mounting frame or the flexible, erectable magnetic field response sensor can be developed to take measurements in hazardous conditions, or in containers with environmentally harmful contents, such as a gasoline storage tank.

Posted in: Physical Sciences, Sensors, Briefs, TSP

Read More >>

Improved Light Injection and Detection Methods for fNIRS Headgear for Use in Avionics and Astronautics

The benefits of the innovation allow the technique to move out of the controlled laboratory and into clinical and operational environments. John H. Glenn Research Center, Cleveland, Ohio Measuring hemoglobin concentration changes in the brain with functional near infrared spectroscopy (fNIRS) is a promising technique for monitoring cognitive state to optimize human performance during both aviation and space operations. The detection and prevention of performance decrement is also relevant to safety-critical operational tasks such as monitoring for air traffic control, performing surgery, and driving. Advances in optical instrumentation for fNIRS have been conceptualized and integrated into several new headgear prototypes designed for use by operators in the real world.

Posted in: Physical Sciences, Briefs, TSP

Read More >>

A High-Cross-Polarization-Isolation, Multi-Frequency Antenna for Cloud and Precipitation Research

Goddard Space Flight Center, Greenbelt, Maryland The Global Precipitation Mission (GPM) has an immediate need for a matched-beam Ku-band/Ka-band antenna system that can be used as a component of a ground validation radar. Retrieval techniques based on both polarization and differential absorption at the two wavelengths can be used to provide additional insight into precipitation type and particle size distribution over a 10- to 40-km spatial domain. These measurements can then be compared with long range radar, such as the WSR-88D, and in situ sensors to provide a comprehensive dataset for evaluating and improving satellite-based precipitation estimates.

Posted in: Physical Sciences, Briefs, TSP

Read More >>

Advanced P-Band Spaceborne Radar System

A new imaging approach can overcome the fundamental limitations of conventional radar systems. Goddard Space Flight Center, Greenbelt, Maryland Low-cost, flexible spaceborne radar architectures are needed to provide critical data for Earth and science applications. An instrument concept was developed for an advanced spaceborne radar system that can measure terrestrial biomass (woody mass per unit area), ecosystem structure (height and density), and extent on a global scale. The PNTB band polarimetric radar architecture employs advanced techniques to increase the science value of the measurements while achieving it at a lower cost. The spaceborne radar concept leverages the existing airborne L-band digital beamforming synthetic aperture radar (DBSAR) and the new P-band digital beamforming (DBF) polarimetric and interferometric EcoSAR (ESTO IIP) architectures that employ DBF and reconfigurable hardware to provide advanced radar capabilities not possible with conventional radar instruments.

Posted in: Physical Sciences, Briefs, TSP

Read More >>

Global Fire Detection Constellation

Small satellites could monitor and process images to track fires from space. NASA’s Jet Propulsion Laboratory, Pasadena, California Wildfires that start in backcountry areas sometimes burn for hours before being detected and reported. Satellites offer a vantage point from which infrared sensors can detect fires. Individual satellites in low Earth orbit (LEO) offer infrequent overpasses, making the delay from ignition to detection unacceptably long. Geostationary satellites offer a platform from which to maintain a round-the-clock vigil, but lack geographic precision, and cannot detect a rather small fire within a large pixel definitively above noise.

Posted in: Physical Sciences, Briefs, TSP

Read More >>