Mechanical & Fluid Systems

Spacecraft Escape Capsule

A report discusses the Gumdrop capsule — a conceptual spacecraft that would enable the crew to escape safely in the event of a major equipment failure at any time from launch through atmospheric re-entry. The scaleable Gumdrop capsule would comprise a command module (CM), a service module (SM), and a crew escape system (CES). The CM would contain a pressurized crew environment that would include avionic, life-support, thermal control, propulsive attitude control, and recovery systems. The SM would provide the primary propulsion and would also supply electrical power, life-support resources, and active thermal control to the CM. The CES would include a solid rocket motor, embedded within the SM, for pushing the CM away from the SM in the event of a critical thermal-protection system failure or loss of control. The CM and SM would normally remain integrated with each other from launch through recovery, but could be separated using the CES, if necessary, to enable the safe recovery of the crew in the CM. The crew escape motor could be used, alternatively, as a redundant means of de-orbit propulsion for the CM in the event of a major system failure in the SM.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Avionics, Electronic control systems, Life support systems, Evacuation and escape, Entry, descent, and landing, Spacecraft

Tool for Torquing Circular Electrical-Connector Collars

A simple tool exerts a strong grip.

An improved tool has been devised for applying torque to lock and unlock knurled collars on circular electrical connectors. The tool was originally designed for, and used by, astronauts working in outer space on the Hubble Space Telescope (HST). The tool is readily adaptable to terrestrial use in installing and removing the same or similar circular electrical connectors as well as a wide variety of other cylindrical objects, the tightening and loosening of which entail considerable amounts of torque.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Connectors and terminals, Tools and equipment, Fasteners

Retaining Device for the Interior Structure of a Spacecraft Payload

Device protects without penalizing interior space.

A device denoted as a bumper assembly for a spacecraft payload container comprises an interior structure surrounded by skin or some other protective enclosure (see figure). When arranged with three or more like assemblies, this bumper assembly is designed to secure the interior structure within a payload’s protective enclosure during the stresses endured in flight and, if required, recovery of the payload. Furthermore, proper use of this innovation facilitates the ability of designers and engineers to maximize the total placement area for components, thus increasing utilization of very valuable and limited space.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Containers, Protective structures, Spacecraft

On Release of Microbe-Laden Particles From Mars Landers

A paper presents a study in which rates of release of small particles from Mars lander spacecraft into the Martian atmosphere were estimated from first principles. Because such particles can consist of, or be laden with, terrestrial microbes, the study was undertaken to understand their potential for biological contamination of Mars. The study included taking account of forces and energies involved in adhesion of particles and of three mechanisms of dislodgement of particles from the surface of a Mars lander: wind shear, wind-driven impingement of suspended dust, and impingement of winddriven local saltating sand particles. Wind shear was determined to be effective in dislodging only particles larger than about 10 microns and would probably be of limited interest because such large particles could be removed by pre-flight cleaning of the spacecraft, and their number on the launched spacecraft would thus be relatively small. Dislodgement by wind-driven dust was found to be characterized by an adhesion half-life of the order of 10,000 years — judged to be too long to be of concern. Dislodgement by saltating sand particles, including skirts of dust devils, was found to be of potential importance, depending on the sizes of the spacecraft-attached particlesand characteristics of both Mars sand-particle and spacecraft surfaces.

Posted in: Briefs, Mechanical Components, Mechanics, Particulate matter (PM), Bacteria, Entry, descent, and landing, Spacecraft

Measurement of Model Noise in a Hard-Wall Wind Tunnel

Spurious noise is suppressed in processing of digitized microphone outputs.

Identification, analysis, and control of fluid mechanically generated sound from models of aircraft and automobiles in special low-noise, semi-anechoic wind tunnels are an important research endeavor. Such studies can also be done in aerodynamic wind tunnels that have hard walls if phased microphone arrays are used to focus on the noise source regions and reject unwanted reflections or background noise. Although it may be difficult to simulate the total flyover or drive-by noise in a closed wind tunnel, individual noise sources can be isolated and analyzed.

Posted in: Briefs, Mechanical Components, Mechanics, Scale models, Noise, Sound quality, Noise, Sound quality, Wind tunnel tests, Aerodynamics

Tilt/Tip/Piston Manipulator With Base-Mounted Actuators

The geometry and kinematics of this manipulator would afford advantages for some applications.

A proposed three degree of freedom (tilt/tip/piston) manipulator, suitable for aligning an optical or mechanical component, would offer several advantages over prior such manipulators:

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Sensors and actuators, Sensors and actuators, Mountings, Pistons

Multifunctional Tanks for Spacecraft

A document discusses multifunctional tanks as means to integrate additional structural and functional efficiencies into designs of spacecraft.  Whereas spacecraft tanks are traditionally designed primarily to store fluids and only secondarily to provide other benefits, multifunctional tanks are designed to simultaneously provide multiple primary benefits. In addition to one or more chamber(s) for storage of fluids, a multifunctional tank could provide any or all of the following:

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Containers, Storage, Spacecraft

Mobile Robot for Exploring Cold Liquid/Solid Environments

This tethered robot could float, swim, crawl, and sample environmental materials.

The Planetary Autonomous Amphibious Robotic Vehicle (PAARV), now at the prototype stage of development, was originally intended for use in acquiring and analyzing samples of solid, liquid, and gaseous materials in cold environments on the shores and surfaces, and at shallow depths below the surfaces, of lakes and oceans on remote planets. The PAARV also could be adapted for use on Earth in similar exploration of cold environments in and near Arctic and Antarctic oceans and glacial and sub-glacial lakes.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Cold weather, Autonomous vehicles, Off-highway vehicles and equipment, Spacecraft

System Would Acquire Core and Powder Samples of Rocks

A sampling system would be built around an ultrasonic/sonic drill corer.

A system for automated sampling of rocks, ice, and similar hard materials at and immediately below the surface of the ground is undergoing development. The system, denoted a sample preparation, acquisition, handling, and delivery (SPAHD) device, would be mounted on a robotic exploratory vehicle that would traverse the terrain of interest on the Earth or on a remote planet. The SPAHD device would probe the ground to obtain data for optimization of sampling, prepare the surface, acquire samples in the form(s) of cores and/or powdered cuttings, and deliver the samples to a selected location for analysis and/or storage.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Soils, Robotics, Test equipment and instrumentation, Autonomous vehicles, Spacecraft

Producing Quantum Dots by Spray Pyrolysis

Sizes of quantum dots are determined by sizes of sprayed drops.

An improved process for making nanocrystallites, commonly denoted quantum dots (QDs), is based on spray pyrolysis. Unlike the process used heretofore, the improved process is amenable to mass production of either passivated or non-passivated QDs, with computer control to ensure near uniformity of size.

Posted in: Briefs, Mechanical Components, Mechanics, Forming, Spraying, Nanotechnology

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