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
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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
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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
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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
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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
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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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Lightweight, Reusable Payload Launch and Transportation Latch

This device can be used for latching cargo in aircraft, supporting hazardous materials, or latching pallets and shipping boxes.

This innovation addresses the problem of automatic engagement and disengagement of payloads from their transport vehicle when lifted by a crane or other material handling device. The prior state-of-the-art is in material handling devices that require personnel to activate the latch, or latches that are actuated by heavy, bulky actuator systems fixed to the transportation device. These require significant accommodations on the transport vehicle to mate to the latch.

Posted in: Briefs, Mechanical Components, Mechanics, Materials handling, Construction vehicles and equipment, Industrial vehicles and equipment
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Structural Assembly Incorporating Integral Thermal Heat Spreader for Cold Plate Cooling

Lyndon B. Johnson Space Center, Houston, Texas

In a structural cold plate, typically there is a structural member such as a honeycomb panel or a brazed sandwich assembly that provides the structural strength, and at least one cold plate that cools equipment attached to the structural member. The cold plate is typically located between the structural member and the item it is cooling. With this configuration, the cold plate’s location, shape, and size are limited to being placed beneath the item it is cooling. This requires an additional envelope that is equal to the cold plate thickness. Being able to locate the cold plate in locations other than beneath the item it is cooling would have multiple benefits including reduced envelope requirements in the direction of the item it is cooling, as well as allowing a larger cold plate cooling footprint.

Posted in: Briefs, Mechanical Components, Cooling, Parts
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Advanced Magnetostrictive Regulator, Valve, and Force-to-Angle Sensor

The components are lightweight, compact, highly precise, and can operate over a wide range of temperatures and pressures.

Typical aerospace rocket engines use valves to control the flow and pressures of propellant and pressurants. These typical valves are designed to operate with a mechanical, electromechanical, or pneumatic operator. They all have at least one, and often multiple, penetrations from the fluid to the operator’s prime mover. The penetrations are sources for leaks, failures, and are often considered to be unreliable for use in single string systems. Therefore, the fluid system designer frequently will utilize several parallel path valves, effectively doubling the resources needed to accomplish the task. These redundant valves allow for isolation of the potentially leaking fluid penetrations. If the systems cannot afford the multiple path approach, then the valves are subjected to high levels of testing and quality control, or utilize bellows or other expensive and difficult to handle/design and costly features.

Posted in: Briefs, Mechanical Components, Mechanics, Computational fluid dynamics, Sensors and actuators, Rocket engines, Transmission valves
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Circular Cross-Section Blades for a Sampling Device

The blades can be used for shallow or deep sampling, low-strength or high-strength sampled media, and consolidated or unconsolidated sampled material.

To date, there are solutions that can collect samples by being deployed from a distance from a low-gravity body or using a touch-and-go approach. To increase precision collection of samples from both consolidated and unconsolidated material, allow for precise sampling location selection, and impart a low impact on the spacecraft, bi-blade sampling devices have been developed.

Posted in: Briefs, Mechanical Components, Mechanics, Materials handling, Spacecraft
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