Physical Sciences

Software for Generating Troposphere Corrections for InSAR Using GPS and Weather Model Data

Atmospheric errors due to the troposphere are a limiting error source for spaceborne interferometric synthetic aperture radar (InSAR) imaging. This software generates tropospheric delay maps that can be used to correct atmospheric artifacts in InSAR data. The software automatically acquires all needed GPS (Global Positioning System), weather, and Digital Elevation Map data, and generates a tropospheric correction map using a novel algorithm for combining GPS and weather information while accounting for terrain.

Posted in: Physical Sciences, Software, Briefs

Read More >>

Implementation of a Wavefront-Sensing Algorithm

A computer program has been written as a unique implementation of an imagebased wavefront-sensing algorithm reported in “Iterative-Transform Phase Retrieval Using Adaptive Diversity” (GSC-14879-1), NASA Tech Briefs, Vol. 31, No. 4 (April 2007), page 32. This software was originally intended for application to the James Webb Space Telescope, but is also applicable to other segmented-mirror telescopes.

Posted in: Physical Sciences, Software, Briefs

Read More >>

Advanced Multimission Operations System (ATMO)

The HiiHat toolbox developed for CAT/ENVI provides principal investigators di rect, immediate, flexible, and seamless in - teraction with their instruments and data from any location. Offering segmentation and neutral region division, it facilitates the discovery of key endmembers and regions of interest larger than a single pixel.

Posted in: Physical Sciences, Software, Briefs

Read More >>

Method of Separating Oxygen From Spacecraft Cabin Air to Enable Extravehicular Activities

Extravehicular activities (EVAs) require high-pressure, high-purity oxygen. Shuttle EVAs use oxygen that is stored and transported as a cryogenic fluid. EVAs on the International Space Station (ISS) presently use the Shuttle cryo O2, which is transported to the ISS using a transfer hose. The fluid is compressed to elevated pressures and stored as a high-pressure gas. With the retirement of the shuttle, NASA has been searching for ways to deliver oxygen to fill the high-pressure oxygen tanks on the ISS.

Posted in: Physical Sciences, Briefs

Read More >>

On-Chip Microfluidic Components for In Situ Analysis, Separation, and Detection of Amino Acids

This innovation can be integrated in a lab-on-a-chip device for biological and analytical instruments. The Astrobiology Analytical Laboratory at GSFC has identified amino acids in meteorites and returned cometary samples by using liquid chromatography-electrospray ionization time-of-flight mass spectrometry (LCMS). These organic species are key markers for life, having the property of chirality that can be used to distinguish biological from non-biological amino acids. One of the critical components in the benchtop instrument is liquid chromatography (LC) analytical column. The commercial LC analytical column is an over-250-mm-long and 4.6-mm-diameter stainless steel tube filled with functionized microbeads as stationary phase to separate the molecular species based on their chemistry. Miniaturization of this technique for spaceflight is compelling for future payloads for landed missions targeting astrobiology objectives.

Posted in: Physical Sciences, Briefs

Read More >>

CRUQS: A Miniature Fine Sun Sensor for Nanosatellites

Size, mass, and power make the sensor suited to small satellite applications, especially nanosatellites. A new miniature fine Sun sensor has been developed that uses a quadrant photodiode and housing to determine the Sun vector. Its size, mass, and power make it especially suited to small satellite applications, especially nanosatellites. Its accuracy is on the order of one arcminute, and it will enable new science in the area of nanosatellites.

Posted in: Physical Sciences, Briefs

Read More >>

Spectroscopic Determination of Trace Contaminants in High-Purity Oxygen

A glow discharge emission system is used to detect and quantify trace amounts of argon in pure oxygen. Oxygen used for extravehicular activities (EVAs) must be free of contaminants because a difference in a few tenths of a percent of argon or nitrogen content can mean significant reduction in available EVA time. These inert gases build up in the extravehicular mobility unit because they are not metabolized or scrubbed from the atmosphere. A prototype optical emission technique capable of detecting argon and nitrogen below 0.1% in oxygen has been developed. This instrument uses a glow discharge in reduced-pressure gas to produce atomic emission from the species present. Because the atomic emission lines from oxygen, nitrogen, and argon are discrete, and in many cases well-separated, trace amounts of argon and nitrogen can be detected in the ultraviolet and visible spectrum. This is a straightforward, direct measurement of the target contaminants, and may lend itself to a device capable of on-orbit verification of oxygen purity.

Posted in: Physical Sciences, Briefs

Read More >>