Physical Sciences

Hydrogen Measurement in a Cryogen Flow Stream Reduces Waste of Helium

Energy conservation and sustainability technologies are applied for propellant conservation.The purpose of this research was to develop an improved method for measuring hydrogen concentrations in a cryogen flow stream to minimize helium waste during the purge process. Currently, this type of measurement is performed manually with a sniffer, and involves obtaining periodic measurements that are not accurate or repeatable and do not optimize the conservation of hydrogen. The goal of this project was to create an autonomous real-time method for continuously measuring hydrogen that potentially offers not only cost saving advantages by conserving expensive resources that are used for purging, but also for providing an additional safety mechanism to monitor hydrogen in a cryogenic flow stream.

Posted in: Briefs, Physical Sciences, Sensors and actuators, Sustainable development, Energy conservation, Propellants


Noncontact DC and AC Magnetostrictive Current Sensor

At the time of this reporting, there have been no effective methods of monitoring current in conductors in space without breaking the circuit or making contact with the conductor. In space, reliability rules all designs, and breaking a circuit to insert a sensor to monitor current would reduce reliability of the system. Hall effect sensors provide a noncontact DC measurement technique, but they are relatively expensive and not rugged enough for the space environment.

Posted in: Briefs, Physical Sciences, Sensors and actuators


Method and Apparatus for Determining Propellant Mass in Microgravity by Capacitance Measurements

The method is relatively insensitive to propellant orientation.Propellant mass gauging in microgravity has posed a challenge for decades. Various methods have been applied, including ultrasonic, capacitance probes, point level sensors, thermal detectors (thermistors, thermocouples, etc.), Michelson interferometry, and nuclear devices. All have problems in terms of how to provide accurate measurements irrespective of the fluid orientation in the tank.

Posted in: Briefs, Physical Sciences, Analysis methodologies, Propellants, Test equipment and instrumentation


Preparation, Planning, and Concept Demo of a Technique to Find ≈7-to-10-m Near Earth Asteroids

A paper describes a new technique designed to increase significantly the sensitivity for finding and tracking small, dim, and fast-moving near Earth asteroids (NEAs). The technique relies on a combined use of a novel data processing approach and a new generation of high-speed CCD cameras. These new cameras have very low readout noise (≈le–) and allow taking short exposures of moving objects at high frame rates, effectively “freezing” their motion on the CCD. A long-exposure image is synthetically created as if the telescope were tracking the object with a significantly higher SNR — an approach called “synthetic tracking.” By changing the shift/add vector, multiple dim objects moving in different directions can be detected in the same data set.

Posted in: Briefs, TSP, Physical Sciences, Imaging and visualization, Data management


Strobing to Mitigate Vibration for Display Legibility

Blur is eliminated with appropriate strobing frequency.This method mitigates the motion blur introduced when a display, and/or the operator reading it, is undergoing vibration (e.g. during the launch phase of spaceflight). If both the operator and the display are undergoing vibration, their respective impulses need not be in phase. This mitigation occurs when the display is illuminated at a strobing rate that corresponds with the frequency of the vibration. This can be done either by strobing the ambient illumination in the environment (e.g., if the operator is reading a reflective surface display), or by strobing the display itself (e.g., strobing the LED backlighting of an electronic display).

Posted in: Briefs, TSP, Physical Sciences, Displays, Vibration


Imaging Space System Architectures Using a Granular Medium as a Primary Concentrator

Higher-resolution optics provide improved hyperspectral imaging for ocean and land monitoring, as well as exoplanet detection.Typically, the cost of a space observatory is driven by the size and mass of the primary aperture. Generally, a monolithic aperture is much heavier and complex to fabricate (hence, more costly) than an aperture of the same size but composed of much smaller units. Formation flying technology, as applied to swarm systems in space, is an emerging discipline.

Posted in: Briefs, TSP, Imaging, Physical Sciences, Architecture, Imaging and visualization


Image Processing Method To Determine Dust Optical Density

Image processing techniques for determining dust optical density in Apollo videos have been developed. The software generates histograms, and calculates the mean and standard deviation, which are then used to match dusty and clear images for the purpose of estimating an effective optical density. A dust thickness model, based on the tilt of the camera and increasing thickness of the dust layer towards the top of the image, is used to account for the distance light travels through dust.

Posted in: Briefs, TSP, Physical Sciences, Imaging and visualization, Optics, Particulate matter (PM)


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