Mechanical Components

Swan Seal

The seal can be sized to any application while maintaining its important features. John H. Glenn Research Center, Cleveland, Ohio This seal features dual sealing capabilities: a face seal and an axial seal. The name swan seal is derived from its cross section, which resembles a swan. Most injector designs require fuel to be delivered from an inlet fitting, through a feed arm, to the injector tip. Temperature variation from the inlet to the tip, from the cool fuel to hot combustion air, and from startup to full power, often poses a challenge due to thermal growth. One of the most challenging areas is accommodating the growth differential between a hot feed arm and a cool fuel delivery tube, which is exacerbated by the relatively long distance. Several methods have been used to allow for this including coiling the fuel tube, utilizing an O-ring sliding seal, metal C-seals, or incorporating stretchable bellows. Some of the drawbacks of these methods include limited space, poor durability at high temperatures, serviceability, long lead times, and cost. The swan seal presents a compact, high-temperature, replaceable, low-cost option for this and other applications where a sliding axial seal is required.

Posted in: Mechanical Components, Briefs, TSP

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Piezoelectric Actuated Valve for Operation in Extreme Conditions

The low-power, compact valve can be used wherever valves are required in harsh environments. NASA’s Jet Propulsion Laboratory, Pasadena, California The extreme conditions on Venus (460 °C and 92 atm) prevent the use of any of the existing science instruments outside of the lander. To transfer a sample into the lander, a pneumatic mechanism was conceived that could bring sample powder into the lander. The mechanism is critically dependent on the availability of valves that can operate at the conditions on Venus. The ability to perform the sample transfer will enable the use of instruments that require direct access to the sample, but cannot sustain Venus’ ambient environment.

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A Field-Reconfigurable Manipulator for Rovers

Applications include bomb disposal, disaster recovery, search and rescue, and law enforcement. Lyndon B. Johnson Space Center, Houston, Texas, and Ames Research Center, Moffett Field, California Robotic technologies will be deeply involved in any future human mission to the Moon. Prior to human arrival, robots will survey and explore the lunar surface, establish infrastructure, and assemble and test habitat modules. Once humans have arrived, the robots must be able to assist human exploration activities. After the humans depart, robots will perform cleanup, maintenance, and documentation tasks. All these various robotic activities will require sensing and manipulation of the environment, but in quite different ways: a survey robot has very different requirements from a habitat assembly robot. It would be inefficient to launch a different robot for each task, yet a single robot capable of performing all of them would be ungainly and impractical. Instead, what is needed is a “kit” of robot parts that can be assembled into the desired robot for each task.

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Lightweight, Flexible, Freezable Heat Pump/Radiator for EVA Suits

The absorption cooling process can be used to provide portable, regenerable refrigeration and air conditioning for recreation, transportation, and medical applications. Lyndon B. Johnson Space Center, Houston, Texas For space exploration missions that may require extended stays and extensive extra-vehicular activity (EVA) operations, the temperature control system must be lightweight, rugged, non-venting, and repairable in space.

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Cryogenic Balloon End Fitting Seal

The seal does not crack or leak at cryogenic temperatures. NASA’s Jet Propulsion Laboratory, Pasadena, California Typical lighter-than-air vehicles utilizing a superpressure design such as balloons, aerostats, or blimps, have one or more fittings attached to the gas containment skin that can serve as load attachment points or inflation/vent ports. These fittings are often sealed to the skin with a silicone gasket and a room temperature vulcanizing (RTV) adhesive. This type of seal works very well over the temperature range encountered in the Earth’s atmosphere (–60 to +40 °C). However, balloons designed to operate at Titan or Mars would encounter temperatures much colder than those found on Earth, making this type of seal inadequate.

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Compact Regenerative Blower

The blower can be used to provide ventilation flow for astronauts in spacesuits, cooling for soldiers wearing body armor, or in personal cooling systems for construction work, law enforcement, or firefighting. Lyndon B. Johnson Space Center, Houston, Texas The regenerative blower provides air flow through structures or systems that have relatively high flow resistance. Specifically, the regenerative blower was designed to provide a flow of ventilation gas through a spacesuit and its portable life support system (PLSS). Since the ventilation gas is primarily oxygen, fire prevention is a critical design requirement.

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Shape-Memory-Alloy-Based Launch Lock

This low-mass, low-power lock can be activated multiple times. NASA’s Jet Propulsion Laboratory, Pasadena, California Most NASA missions require the use of a launch lock for securing moving components during the launch or securing the payload before release. A launch lock is used to prevent unwanted motion and secure the controlled components. The current launch locks are based on pyrotechnic, electromechanical or NiTi-driven pin pullers that are one-time activation mechanisms. Generally, the use of piezoelectric activation provides high-precision nanometer accuracy, but they rely on friction to generate displacement. During launch, the generated vibrations can release the normal force between the actuator components, allowing the shaft’s free motion, which could result in damage to the actuated structures or instruments. This problem is common to other linear actuators that consist of a ball screw mechanism. There are many mechanisms that require the capability of being activated multiple times, and the disclosed concept addresses this need.

Posted in: Mechanics, Mechanical Components, Briefs, TSP

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