Mechanical & Fluid Systems

Technology for a Comet Sample Return Mission Version 2

Harpoon-based sample collectors with rectangular cross-sections are regarded as the best candidates. Goddard Space Flight Center, Greenbelt, Maryland A standoff sample collection system would be capable of quickly obtaining a sample from environments as varied as comets, asteroids, and permanently shadowed craters on the Moon from vehicles ranging from traditional planetary spacecraft to platforms such as hovering rotorcraft or balloons at Mars, Venus, or Titan. The depth of penetration for this harpoon-based hollow collector design was experimentally determined to be proportional to the momentum of the penetrator, in agreement with earlier work on the penetration of solid projectiles. A release mechanism for the internal, removable sample cartridge was tested, as was an automatic closure system for the sample canister and tether recovery approaches.

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


Nitrous Oxide Ethane-Ethylene Engine

Marshall Space Flight Center, Alabama The Nitrous Oxide Ethylene-Ethane (NEE) engine uses nitrous oxide as an autogenously pressurizing oxidizer, and a mixture of ethane and ethylene is used in the same manner as fuel. Initially, the ethane and ethylene mixture has the same vapor pressure as the nitrous oxide. By using the autogenous pressurization capabilities of these propellants, instead of an additional pressurization system, greater system simplicity and reliability can be attained. The NEE can obtain a specific impulse of 320 s, making it the highest-performing, non-toxic, storable bipropellant rocket propulsion system in existence at the time of this reporting.

Posted in: Briefs, Mechanical Components, Propellants, Spacecraft fuel, Rocket engines


Method for Improved Gun-Drilled Cold Plate Fabrication and Inspection

A method was developed for obtaining proper fluid distribution through parallel gun-drilled passages and for being able to inspect the actual drilled passages to guarantee that the designed minimum wall thickness is not violated. This invention uses one feature that addresses both issues mentioned. By machining a “trough” in the center of the cold plate that intersects the gun-drilled passages where they meet in the center, the area where the two drilled passages intersect is removed and any mismatch is eliminated. This allows access for direct inspection of the drill wander. An integral cap, which incorporates orifice features to address the fluid distribution, is then inserted into this trough. This method can also work in a two-layer cold plate where every other fluid passage is for the alternating fluid layer.

Posted in: Briefs, Mechanical Components, Mechanics, Fabrication, Machining processes, Inspections


Powder Handling Device for Analytical Instruments

Powder is handled as a fluid via equipment that requires few or no moving parts. Ames Research Center, Moffett Field, California A new technology provides for automated sample handling and movement of coarse-grained powder or other solid materials to enable analysis by a robotic or totally automated computer system. Currently, many analytical instruments require a powder sample to control the shape and/or volume of the specimen, to increase the surface area of the specimen, to increase the statistical representation of a specimen when samples are not homogeneous with regard to the characterized property, and/or to increase the statistical representation of the specimen spatial orientation when the properties being characterized are not equivalent in different viewing directions. Grinding the material down to an ideal grain size is sometimes impossible, and conditioning the sample for analysis is often time-consuming and labor-intensive. In the new approach, the powder is handled as a fluid, using mechanical vibrations in conjunction with a driving force (gravity or gas flow), and requiring few or no moving parts.

Posted in: Briefs, Mechanical Components, Test equipment and instrumentation


Universal Mechanical Testers for Tribology Testing in the Automotive Industry

Universal mechanical testers provide tribology testing for friction, wear, coatings, and lubrication in macro, micro, and nano regimes. Very few industries are as affected by strict test standards as the automotive sector. Nearly every automobile component (engine parts, accelerators, clutches, brakes, tires, seatbelts, etc.) must exhibit adequate tribological properties in accordance with ASTM, DIN, JIS, ISO, and other comprehensive international standards. Universal mechanical testers (UMTs) that are able to perform multiple tests in a single platform with interchangeable modules can help manufacturers meet test specifications quickly and economically. For example, crankshafts and camshafts have critical requirements for proper functioning under diverse service conditions. Tests include evaluation of base materials, heat-treated parts, surface coatings, and lubricants. Tests can be run with diverse loads, velocities, and temperatures that simulate actual service conditions using various lubricants and liquids.

Posted in: Briefs, Mechanical Components, Mechanics, Test & Measurement, Lubricants, Coatings, colorants, and finishes, Tribology, Wear, Test equipment and instrumentation, Test procedures


Fail-Safe Accumulator for Internal Active Thermal Control Loops

Spacecraft internal active thermal control systems (ATCSs) typically use water or a water mixture as their working fluid. A gas-charged bellows accumulator pressurizes the system and provides liquid inventory control. If only a single internal ATCS loop is used, the accumulator represents a single-point failure that can result in a loss of crew. To protect against this possibility, the normal practice is to add a second, fully redundant loop. A redundant loop requires duplication of cold plates, heat exchangers, and plumbing, even though these items are themselves highly reliable. Duplicating these reliable piece parts to protect against accumulator failure adds significant mass to the spacecraft.

Posted in: Briefs, Mechanical Components, Mechanics, Thermal management, Cooling, Spacecraft


Rocket Vent Design With Variable Flow Control and Rain Protection

Rugged design will ensure operation from pre-flight through flight.This innovation is a rocket purge vent design that can control and balance flow across multiple vents and across very large gas flow ranges while keeping water or other undesirable gases from entering into the vented space. When changing purge rates, this device adapts to the different flow rates to maintain a very low internal delta pressure. It provides a vent design that can withstand high winds and blowing rain without allowing water entry. With the rugged design, it can operate during all rocket operational phases, from pre-flight operations through flight. This design is useful for any device needing a one-way valve type purge or general air vent where rain and gas reverse entry must not occur.

Posted in: Briefs, Mechanical Components, Mechanics, Exhaust valves, Rocket engines


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