Mechanical & Fluid Systems

Passive, Low-Insertion-Force/High-Retention-Force Cam Plug Design for Sample Tube Sample Caging

This plug could be used for soil and sediment samples in petroleum and mining industries, or to plug products of various sizes tightly in tubes for shipping.

NASA’s Jet Propulsion Laboratory, Pasadena, California

AMars “sample caching rover” mission designed to collect, document, and package samples for future collection and return to Earth was recommended as the highest-priority mission for 2013–2022 by the 2011 Planetary Decadal Survey. A key premise of the Mars 2020 rover, which will gather samples for potential future return, is that it should be possible for the samples to be packaged and left on Mars for an extended period of time (at least five Mars years) without loss of scientific value. Two particularly important characteristics of a sample are the structure and relative positioning of the rock fragments and grains. These characteristics can be affected by shock and vibration that could fracture the sample and create relative movement among the fragments and grains, and therefore cause loss of valuable scientific information.

Posted in: Briefs, Mechanical Components, Packaging, Vibration, Test equipment and instrumentation, Spacecraft

Design Support and Analysis Tool for Pyrotechnically Actuated Valves

Lyndon B. Johnson Space Center, Houston, Texas

This software predicts flow through the initiator of a Primer Chamber Assembly Valve. These valves exhibited a potential failure mode for specific operating conditions where dual simultaneous firings of the initiator occurred. The software tool was able to identify a fluid dynamic source for this potential failure mode. Furthermore, the software was also used to provide new conceptual designs that may alleviate or eliminate these failure modes.

Posted in: Briefs, Mechanical Components, Computational fluid dynamics, Failure modes and effects analysis, Sensors and actuators, Valves

Deployable Extra-Vehicular Activity Platform (DEVAP) for Planetary Surfaces

Potential applications include stable work ramps for vehicles, vessels, or portable shelters.

The Deployable Extra-Vehicular Activity Platform (DEVAP) is a staging platform for egress and ingress attached to a lunar, Mars, or planetary surface habitat airlock, suitlock, or port. The DEVAP folds up into a compact package for transport, and deploys manually from its attached location to provide a ramp and staging platform for extravehicular activities (see figure).

Posted in: Briefs, Mechanical Components, Mechanics, Spacecraft

Two-Phase Thermal Switch

The switching mechanism is passively triggered by the temperature of the heat source.

Marshall Space Flight Center, Alabama

There is a wide range of spacecraft thermal management applications that require variable conductance devices such as thermal switches. These switches are used to help maintain the heat source (electronics) temperature under varying thermal loads and varying thermal environments. These applications include satellites and Lunar and Mars landers and rovers, as well as future human spacecraft that may transit through both the cold environment of deep space and warm transient environments such as low lunar orbit.

Posted in: Briefs, Mechanical Components, Electronic equipment, Switches, Thermal management, Spacecraft

Save Your Assembly Space and Weight with Smalley Wave Springs

Smalley Wave Springs offer the unique advantage of space savings when used to replace coil springs. By reducing spring operating height, wave springs also produce a decrease in the spring cavity and assembly size.

Posted in: White Papers, Mechanical Components, Mechanics, Motion Control, Automation, Robotics

Reliable VFD Cables Boost Productivity, Minimize Downtime

From fans and blowers to 24/7 production line equipment, variable frequency drives (VFDs) are a mainstay of the industrial world due to their remarkable ability to improve the efficiency of motor-driven equipment. As part of a complete VFD package, high quality cable is one of the most important components in terms of achieving maximum productivity and minimizing downtime. When designing a robust VFD cable, the materials used in its production are critical to ensuring that the cable’s electrical properties will guarantee peak performance. For system engineers and others involved in specifying VFDs, cable quality should be one of the most decisive factors.

Posted in: White Papers, Aerospace, Defense, Mechanical Components, Mechanics, Motion Control

Constraint Force Equation (CFE) Solver for Multi-Body Dynamics and its Implementation in POST2

Langley Research Center, Hampton, Virginia

Existing aerospace flight trajectory programs simulate the motion of aerospace vehicles by modeling external forces and moments acting on each body, but lack provisions for determining reaction forces and moments exerted by one body on another through a connecting joint. These reaction forces and moments are also known as constraint forces and moments because they permit specified motion of one body relative to another, and, at the same time, prohibit all other relative motions. In other words, a joint imposes certain constraints on relative motion.

Posted in: Briefs, Mechanical Components, Trajectory control, Computer simulation, Aerodynamics

Cyclops: the Space Station Integrated Kinetic Launcher for Orbital Payload Systems (SSIKLOPS)

Lyndon B. Johnson Space Center, Houston, Texas

The Space Station Integrated Kinetic Launcher for Orbital Payload Systems (SSIKLOPS), also known as “Cyclops,” deployed the largest satellite ever from the International Space Station (ISS) on November 28, 2014. The satellite, SpinSat, a Naval Research Laboratory (NRL)/Department of Defense Space Test Program (DoD STP) satellite, is pioneering the utilization of electronically controlled solid propellant thrusters as well as acquiring vital atmospheric density data. It is a spherical satellite 22 inches in diameter, weighing 115 pounds, and will remain in orbit for over two years.

Posted in: Briefs, Mechanical Components, Electronic control systems, Solid propellants, Military aircraft, Satellites

Vacuum-Jacketed Cryogenic Flex-Through

John F. Kennedy Space Center, Florida

A vacuum-jacketed, cryogenic flex hose was designed with an integrated flange to be able to pass through a vacuum chamber wall. This design increases the quality of the cryogenic fluid at the exit of the hose (i.e., more liquid, less vapor) by extending the hose vacuum-jacket through the chamber wall, where usually a non-insulated fluid fitting would be required.

Posted in: Briefs, Mechanical Components, Insulation, Fittings, Hoses

Normally-Closed Zero-Leak Valve with a Magnetostrictive Actuator

The valve can be used wherever normally closed valves are required.

Goddard Space Flight Center, Greenbelt, Maryland

A hermetically sealed, normally closed (NC) zero-leak valve has been developed. Prior to actuation, the valve isolates the working fluid in the upstream volume from the downstream volume with a parent metal seal. The valve utilizes the magnetostrictive alloy Terfenol-D for actuation. This alloy experiences a phenomenon known as magnetostriction, i.e., a gross elongation, when exposed to a magnetic field. This elongation fractures the seal within the wetted volume of the valve, opening the valve permanently and establishing fluid flow. The required magnetic field is generated by redundant coils concentric to the Terfenol, but isolated from the working fluid. The response time for this phenomenon to occur and subsequently for actuation is on the order of milliseconds. The wetted volume consists of entirely parent-metal 6Al-4V titanium, compatible with all storable propellants, helium, nitrogen, argon, isopropyl alcohol, and argon. When coupled with the parent metal seal, this design gives the valve internal and external leak rates of zero.

Posted in: Briefs, Mechanical Components, Ferrous metals and alloys, Magnetic materials, Seals and gaskets, Valves

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