Mechanical & Fluid Systems

Elastic Deployable Composite Tubular Roll-Out Boom

Goddard Space Flight Center, Greenbelt, Maryland The objective of this work was to develop an innovative deployable boom/structure technology that is ultra-lightweight (<30-grams/meter potential), and has extremely compact stowage volume (>100:1 compaction ratio), broad scalability (no size limits envisioned), high deployed frequency, high deployed strength, good thermal/dimensional stability, reliable/immediate and repeatable controlled deployment, high stiffness maintained during the entire deployment sequence, affordability (simple, easily produced tubular structure, very low parts count, and proven tube manufacture provides low cost and rapid assembly), space environmental survivability, and broad mission applicability.

Posted in: Briefs, TSP, Aerospace, Mechanical Components, Composite materials, Lightweighting

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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

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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

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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

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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

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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

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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

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