Special Coverage


Ground-to-Space Laser Calibration System

This is a space-focused application located on the ground, which makes it easily accessible for maintenance and development. Langley Research Center, Hampton, Virginia The accuracy of spaceborne sensors measuring reflected solar radiance can be affected by multiple factors. First, instruments with complex optics are sensitive to polarization. The response of such instruments is characterized before launch; however, sensitivity to polarization can change on orbit significantly. None of the existing on-orbit sensors has the ability to monitor its sensitivity to polarization on orbit. Another factor is the degradation of optics, particularly in blue wavelength range below 500 nm. Currently, there is no reliable method to access spectral changes in the optics of instruments on orbit. The third factor contributing to changes in on-orbit calibration is the instrument response to stray light. The prior method of correcting radiometric measurement for polarization effects was based on vicarious calibration to the SeaWIFS instrument, which was designed not to be sensitive to polarization.

Posted in: Sensors, Articles, Briefs, TSP


Process-Hardened, Multi-Analyte Sensor for Characterizing Multiple Rocket Plume Constituents in a Test Environment

A multi-analyte measurement capability is integrated into a single sensor. Stennis Space Center, Mississippi Stennis Space Center (SSC) is one of three government-operated rocket engine test facilities in the United States and is the primary center for testing and flight-certifying rocket propulsion systems for future space vehicles. Safety is a top priority at NASA-SSC. To safely test and certify rocket engines, monitoring technologies for rocket test stands, which (1) verify compliance with federal, state, and local government guidelines; (2) ensure a safe work environment for its personnel at ground testing facilities; as well as (3) monitor environmental impacts, are all required. Additionally, NASA has a need to monitor engine combustion efficiencies and engine health of a variety of launch vehicle configurations utilizing liquid oxygen, liquid hydrogen, isopropanol, and kerosene. Multi-analyte measurement technology is essential for a safe and effective working environment. Therefore, for the advancement in multi-analyte technology in the rocket testing industry, a device was created that integrates multi-analyte measurements into a single sensor unit.

Posted in: Sensors, Test & Measurement, Monitoring, Articles, Briefs


PATTERNS: Panoptic Aspect Time Triggered Ethernet Robust Network Scheduler, Version 1.0

Lyndon B. Johnson Space Center, Houston, Texas The PATTERNS scheduling tool was created to test the multi-plane concept of a Time Triggered Ethernet (TTE) network. The TTE network interface cards used in the Orion vehicle contain three physical network ports, referred to as planes. Each plane exists to serve as a redundant communication channel for each link in the network. The scheduler used prior to PATTERNS was the vendorprovided demonstration tool, TTE-demo-scheduler, which was unable to schedule Ethernet traffic in a manner that would allow the plane-specific and plane-independent tests required to be performed.

Posted in: Electronics & Computers, Articles, Briefs, TSP


Electromagnetic Waves Transformed from a Coherent to a Quasi-Coherent Nature

NASA’s Jet Propulsion Laboratory, Pasadena, California The transformation of naturally occurring electromagnetic waves called “chorus” from a coherent nature to a quasi-coherent nature when propagating a distance from its source was demonstrated. The aim of the mission was to study the energizing of electrons by the waves and also the loss of these particles by interaction with the waves. Both of these processes will be affected by the quasi-coherent nature of chorus. This work indicates that if coherent waves are not propagated in enhanced ionization ducting, the waves will become only quasi-coherent, and their effect of scattering trapped particles will be substantially diminished.

Posted in: Electronics & Computers, Articles, Briefs


An Earth-Observing, Frequency-Agile Radar Receiver for RFI Mitigation

Applications include automotive collision-avoidance radar, cellular phone networks, and radar surveillance sensors for unmanned vehicles. NASA’s Jet Propulsion Laboratory, Pasadena, California The Soil Moisture Active Passive (SMAP) mission will have the first L-band radar/radiometer sensor suite dedicated to global measurements of soil moisture. For the radar sensor, the requirements for achieving high backscatter measurement accuracy from low-Earth orbit present a unique design challenge in the presence of terrestrial radio frequency interference (RFI). The SMAP radar shares the same 1,215 to 1,300 MHz spectrum used by high-power ground-based transmitters like air-route and defense surveillance radars, which can generate strong interference in a conventional fixed-frequency spaceborne radar. The noisy ground environment motivated the development of a frequency-hopping (self-tuning) feature in the radar design. As the SMAP spacecraft orbits across various regions of the Earth, the radar continually adjusts its RF operating frequency to quieter areas of the spectrum for improved fidelity in soil-moisture science data observations.

Posted in: Electronics & Computers, Articles, Briefs, TSP


Wireless Electrical Devices Using Floating Electrodes

Langley Research Center, Hampton, Virginia A wireless, connection-free, open circuit technology can be used for developing electrical devices like sensors that need no physical contact with the properties being measured. At the core of the technology is the SansEC (Sans Electrical Connections) circuit that is damage-resilient and environmentally friendly to manufacture and use.

Posted in: Electronics & Computers, Sensors, Articles, Briefs, TSP


Web-Enabled and Automatic Ground Processing Infrastructure Servicing the UAVSAR Airborne Missions

NASA’s Jet Propulsion Laboratory, Pasadena, California The UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar) ground data processing infrastructure facilitates a wide range of mission operational processes through a centralized database, Web-enabled interfaces, and background automation. By tracking flight request submissions and flight planning activities, the database provides the most up-to-date historical records on how and when flight missions took place, as well as what radar data were collected. As data-collection missions wrap up, post-mission reports are uploaded to the database via a Web interface, while raw data are scanned into the database enabling the operator to perform polarimetric/interferometric processing on the radar data.

Posted in: Electronics & Computers, Data Acquisition, Aviation, Articles, Briefs, Aeronautics