Mechanical & Fluid Systems

Reduced-Speed Duplex-Ring Seal

This configuration seals fluid flow and pressure at a significant increase in machine shaft speed.

John H. Glenn Research Center, Cleveland, Ohio

Ring seals are used in rotating union applications where a fluid flow or hydraulic pressure signal is transferred from a static reference frame to a rotating component, such as a shaft, for the purpose of providing lubrication and/or a hydraulic signal to a component(s) in a rotating frame of reference. Ring seals are used in physically compact configurations.

Posted in: Briefs, TSP, Mechanical Components, Seals and gaskets

Performing Launch Depressurization Test on Large Test Articles Using Two Vacuum Chambers in Tandem

NASA’s Jet Propulsion Laboratory, Pasadena, California

Two vacuum chambers were used in tandem to perform a launch depressurization test. The test article was mounted in a 10-ft (≈3 m) Vertical Vacuum Chamber (Chamber 248-10). The 25-ft (≈7.6-m) Space Simulator (Chamber 150-25) was rough-pumped and used for ullage.

Posted in: Briefs, TSP, Aerospace, Mechanical Components, Test procedures

Pyramid Micro-Electrofluidic-Spray Propulsion Thruster with Integrated Attitude and Thrust Vector Control

NASA’s Jet Propulsion Laboratory, Pasadena, California

A micro-electrofluidic-spray propulsion (MEP) system was built on a micro scale, in which arrays of hundreds of nano-thrusters are etched on silicon wafers like ICs, only a centimeter on a side. Many dozens of these thruster chips can be arrayed to form a macro-thruster of finite and significant thrust. Approximately 300 centimeter-square, 100-micro-Newton micro-thrusters are arrayed in a square pyramidal structure. The pyramid is of shallow obliquity, with no more than 20° offset from the spacecraft face. This small angular offset is sufficient to provide thrust vector control (TVC) for the thruster.

Posted in: Briefs, Aerospace, Mechanical Components, Nanotechnology, Propulsion, Semiconductors & ICs

Sampling Mechanism for a Comet Sample Return Mission

A similar sampling mechanism could be deployed in dangerous situations on Earth.

Goddard Space Flight Center, Greenbelt, Maryland

Sample return missions have the ability to vastly increase scientific understanding of the origin, history, current status, and resource potential of solar system objects including asteroids, comets, Mars, and the Moon. However, to make further progress in understanding such bodies, detailed analyses of samples are needed from as many bodies as possible. A standoff sample collection system concept has been developed that would quickly obtain a sample from environments as varied as comets, asteroids, and permanently shadowed craters on the Moon, using vehicles ranging from traditional planetary spacecraft to platforms such as hovering rotorcraft or balloons on Mars, Venus, or Titan. The depth of penetration for this harpoon- based hollow collector was experimentally determined to be proportional to the momentum of the penetrator in agreement with earlier work on the penetration of solid projectiles. A release mechanism for the internal, removable sample cartridge was tested, as was an automatic closure system for the sample canister.

Posted in: Briefs, TSP, Aerospace, Data Acquisition, Mechanical Components, Automation, Monitoring, Test facilities, Spacecraft

MEMS Gyroscope with Dual Interferometric Sense Elements

This sensing technique enables the use of a large proof mass with very low thermomechanical noise.

John F. Kennedy Space Center, Florida

High-performance inertial sensors, such as ring laser gyroscopes or fiber optic gyroscopes, have sufficient performance to enable “dead reckoning” navigation for adequate periods of time. Smaller microelectromechanical system (MEMS) inertial sensors, such as MEMS gyroscopes and MEMS accelerometers, typically have relevant performance characteristics that are 10 or 100 times worse than high-performance inertial sensors. As a result, these small MEMS inertial sensors must be aided by a global positioning system (GPS) if they are to be used for navigation.

Posted in: Briefs, TSP, MEMs, Sensors, Sensors and actuators, Sensors and actuators

Piezoelectric Actuated Inchworm Motor (PAIM)

This linear piezoelectric actuator can operate at temperatures of 77 K or below.

NASA’s Jet Propulsion Laboratory, Pasadena, California

Conventional piezoelectric materials, such as PZTs, have reasonably high electromechanical coupling over 70%, and excellent performance at room temperature. However, their coupling factor (converting electrical to mechanical energy and vice versa) drops substantially at cryogenic temperatures, as the extrinsic contributions (domain wall motions) are almost frozen out below 130 K.

Posted in: Briefs, TSP, Energy, Fluid Handling, Motors & Drives, Electric motors

Design for Improving the Flatness of Solar Sails

An optically flat solar sail could be useful in optical communication and solar energy applications.

NASA’s Jet Propulsion Laboratory, Pasadena, California

This work describes a discontinuous or segmented mirror whose overall flatness is less dependent on the limited tension that can be supplied by the booms. A solar sail is a large, nominally flat sheet of extremely thin reflectorized film rigidly attached to a spacecraft, enabling propulsion via solar radiation pressure. Rip-stop fibers embedded in the backside of the film — with diameters ≈100× the thickness of the film — are commonly used to arrest tear propagation, which can easily occur in the handling and/or deployment of these gossamer-thin structures. Typically, the thin film or membrane that is the sail is systematically folded to enable both volumetrically compact transportation to space and mechanized deployment. It is the aggressive folding and creasing of the thin film that limits the ultimate flatness that can be achieved.

Posted in: Briefs, TSP, Communications, Energy, Solar Power, Mechanical Components, Solar energy, Spacecraft

Reactionless Drive Tube Sampling Device and Deployment Method

Springs and a counter-mass create a powerful and stable sampling device.

NASA’s Jet Propulsion Laboratory, Pasadena, California

A sampling device and a deployment method were developed that allow collection of a predefined sample volume from up to a predefined depth, precise sampling site selection, and low impact on the deploying spacecraft. This device is accelerated toward the sampled body, penetrates the surface, closes a door mechanism to retain the sample, and ejects a sampling tube with the sample inside. At the same time the drive tube is accelerated, a sacrificial reaction mass can be accelerated in the opposite direction and released in space to minimize the momentum impact on the spacecraft. The energy required to accelerate both objects is sourced locally, and can be a spring, cold gas, electric, or pyrotechnic. After the sample tube is ejected or extracted from the drive tube, it can be presented for analysis or placed in a sample return capsule.

Posted in: Briefs, TSP, Mechanical Components, Motors & Drives, Drilling, Test equipment and instrumentation, Spacecraft

Nozzle Heat Flux Gauge

Marshall Space Flight Center, Alabama

This innovation is a tungsten-rhenium gauge that can be placed into an aft exit cone of a rocket motor. It will measure heat flux with time for the full duration of the RSRM (reusable solid rocket motor) nozzle environment with equal response time.

Posted in: Briefs, Mechanical Components, Measuring Instruments, Nozzles, Rocket engines, Thermal testing

Rotary-Hammer Core Sample Acquisition Tool

This tool can be used for drilling in construction, mining, or scientific research applications.

NASA’s Jet Propulsion Laboratory, Pasadena, California

NASA is developing technologies to enable in situ analysis and sample acquisition from planetary bodies. Missions to these diverse locations require autonomous, highly customizable, reliable tools. A tool capable of core generation, capture, and transfer, and customizable for different missions, would be very valuable.

Posted in: Briefs, TSP, Data Acquisition, Mechanical Components, Tools and equipment, Drilling, Test equipment and instrumentation

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