Mechanical & Fluid Systems

Piezoelectric-Actuated Rotary Ultrasonic Motor

This motor can be used where rotary actuation is required, particularly in cryogenic and high-temperature applications. NASA’s Jet Propulsion Laboratory, Pasadena, California This actuator was developed out of a need for a cryogenic actuator that can operate effectively in spite of the thermal mismatch involved with construction materials that have different expansion coefficients. Also, there is a need for a cryogenic motor that can drive infrared systems and produce minimal thermal energy that can interfere with their operation.

Posted in: Briefs, Mechanical Components, Mechanics, Automation, Sensors and actuators, Thermal management, Materials properties


How to Prevent Step Losses with Stepper Motors

While stepper motors are an excellent solution for many applications, a key concern is step losses. However, in most instances step losses can be prevented or corrected. It is important to remember that a stepper motor does not operate like a DC motor. This white paper from MICROMO engineers provides guidance to determine step losses or non-operation across a variety of applications.

Posted in: White Papers, White Papers, Mechanical Components, Medical, Motion Control, Motors & Drives


Launch Tie-Down and Release Mechanism for CubeSat Spacecraft

This hardware configuration takes up an extremely small volume inside the CubeSat bus. NASA’s Jet Propulsion Laboratory, Pasadena, California As CubeSats take on increased functionality, including larger solar arrays for increased power demands and large antennas for science and communications needs, the requirements for launch tie-down and release mechanisms are evolving. In the past, some large CubeSat-deployable structures (solar arrays) relied on the confining walls of the CubeSat canister to act as the restraint mechanism. However, this practice is largely eliminated now, with most CubeSat specifications requiring a minimum amount of dwell time (after the CubeSat has been ejected from its parent canister) before the deployable structure can be released and deployed on orbit. Thus, a reliable restraint and release mechanism that does not depend on the geometry of the canister walls must be implemented.

Posted in: Briefs, Mechanical Components, Antennas, Packaging, Launch vehicles, Satellites


Ratcheting Threaded Tapered Collet for use in Planetary Sample Caching Systems

The desired sample tube preload can be tailored to specific applications, and allows each sample to be individually secured. NASA’s Jet Propulsion Laboratory, Pasadena, California Aridged retention interface is necessary to secure planetary sample tubes within a caching system for use in future sample return missions. The assumed retention interface requirements are as follows: the interface shall maintain sample integrity at large deceleration landing loads; the interface shall minimize weight and complexity; and any required actuation for sample tube retention shall be performed by an external source (such as a robotic end-effector).

Posted in: Briefs, Mechanical Components, Containers, Mountings, Entry, descent, and landing


Planetary Ice Mining by Down-Hole Energy Injection

This lightweight technology operates in low gravity with energy efficiency. John F. Kennedy Space Center, Florida Ice has been discovered on Mars and is present in the permanently shadowed craters on the Moon and on many asteroids. The ice is usually buried beneath an overburden of regolith. Evidence indicates this overburden may be a meter deep in some locations for the Moon; for Mars, it varies with latitude and may be as deep as or deeper than two meters in many locations. To obtain this ice as a resource in usable quantities, existing technology will require that it be strip-mined.

Posted in: Briefs, Mechanical Components, Water, Mining vehicles and equipment, Spacecraft


The Ultimate Shaft-To-Hub Connection

Polygon Shapes - Multi-Faceted Problem Solvers Kinematically ground polygonal shapes have been used as drive connections for more than 45 years. What is now referred to as Polygon Systems was developed by Fortunawerke, Stuttgart, West Germany, who patented a grinding machine capable of producing matched polygonal shaft and bore diameters.

Posted in: White Papers, White Papers, Mechanical Components, Mechanics


Integrated Epoxy Feedthroughs Improve Fuel Pump Reliability

Of all the design decisions that affect the operation of an in-tank fuel pump, the way you seal the pump housing may top the list. A bad seal will allow liquid fuel to work its way into the housing, which will eventually corrode the electronics and potentially cause a risk of fire.

Posted in: White Papers, Aeronautics, Defense, Mechanical Components, Mechanics


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