Mechanical & Fluid Systems

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

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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.

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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.

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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.

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Pyrotechnically Actuated Gas Generator Using Aqueous Methanol

This gas generator ensures successful inflation of a supersonic pilot ballute. NASA’s Jet Propulsion Laboratory, Pasadena, California The largest supersonic parachute ever developed is one of the test articles on the Supersonic Flight Dynamics Test (SFDT) vehicle of the Low Density Supersonic Decelerator (LDSD) project. The typical method for deploying a supersonic parachute from an entry vehicle, by firing it from a mortar, is not viable for this application due to its noncentral location on the vehicle and the associated high reaction force. Instead, the parachute is pulled off the vehicle using the Parachute Deployment Device (PDD). The PDD uses a ballute, a smaller, balloon-like, soft-good drag body that maintains positive internal pressure by ingesting air at supersonic speeds through a set of ram-air inlets. The PDD, being significantly smaller than the supersonic parachute, is deployed using a mortar.

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Deployable Perimeter Truss with Blade Reel Deployment Mechanism

Applications include pop-up tents, deployable deck awnings, and pop-up lawn chairs. NASA’s Jet Propulsion Laboratory, Pasadena, California Solar sail technology depends heavily on the total surface area of the sail. In other words, minimizing mass and volume of its support structure is the main objective, particularly when it comes to launch configuration, i.e. mass, volume constraints, etc. There is a need to develop a low-cost concept of a deployable support structure that can stow in the EELV Secondary Payload Adapter (ESPA) volume, and carries as much sail material as possible. This structure must then be able to deploy the sail material out, and provide the surface area needed.

Posted in: Briefs, TSP

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Cantera Integration with T-MATS

John H. Glenn Research Center, Cleveland, Ohio The Toolbox for the Modeling and Analysis of Thermodynamic Systems (TMATS) software package is a library of building blocks that can be assembled to represent any thermodynamic system in the Simulink® (MathWorks, Inc.) environment. These elements, along with a Newton Raphson solver (also provided as part of the T-MATS package), enable users to create models of a wide variety of systems. The updated version of T-MATS (v1.1.1) includes the integration of Cantera, an open source thermodynamic simulation tool. T-MATS was initially described in detail in LEW-19165-1, "Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS)", Software Tech Briefs (September 2014), p. 11.

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