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At least 613 records · Page 34

Transphoresis and isotachophoresis as preparative techniques with reference to zero-gravity

Transphoresis and isotachophoresis are high resolution electrophoretic separation methods for biological materials. They benefit substantially from a weightless environment. Low power consumption and apparatus payload per unit product yield reflect their high electrophoretic efficiency. Properties unique to these systems, including their imposition of self-stabilizing geometry, suggest novel apparatus automatically controllable by largely electrical means with few or no moving parts. Configurations allowing continuous and semicontinuous operation, and further improvement of efficiency, are discussed.

Hinckley, J. O. N.↗

A material fatigue test machine for space orbital application

A prototype fatigue test machine has been designed and fabricated which is suitable for use by an astronaut in conducting constant amplitude materials fatigue tests aboard a Skylab or a shuttle space vehicle. The machine is comprised of a mechanical tester, which would be passed through a small airlock to be supported in the space environment on an extendible boom, and a control console, which would provide remote control from within the space vehicle. The tester is a resonance machine which operates at approximately 60 Hz; vibratory mechanism is symmetrically arranged to minimize external reaction. A control system employing stabilized servo-loop circuits about both mean and varying load components maintains loading accuracy to better than two percent. Specimen installation and control console details are simplified for astronaut use. Power consumption from a 28 volt supply is estimated at between 50 and 80 watts.

Sandorff, P. E.↗

Fluxgate magnetometers for outer planets exploration

The exploration of the interplanetary medium and the magnetospheres of the outer planets requires the implementation of magnetic field measuring instrumentation with wide dynamic range, high stability, and reliability. The fluxgate magnetometers developed for the Pioneer 11 and Mariner-Jupiter-Saturn missions are presented. These instruments cover the range of .01 nT to 2 million nT with optimum performance characteristics and low power consumption.

Acuna, M. H.↗

A nondispersive infrared analyzer

Apparatus retains all advantages of prior nondispersive infrared analysis systems and provides significantly more innumity to type of errors that may be introduced by geometric changes in analysis system. Technique also permits construction of instruments of lower weight, smaller volume, and smaller power consumption.

Dimeff, J.↗

Prospects for the development of phototelevision methods in space studies

In-space imaging of the surface of celestial bodies can be carried out by both television and photographic equipment. Television equipment of various types has the important property of being capable of transmitting imagery in real time. Frequently this is not possible because of the nature of information transmission over the spacecraft-ground communication line. The inadequate energy handling capacity of the communication lines usually requires storage of the video information aboard the spacecraft for subsequent transmission at a definite time and rate. For this purpose, the television camera can be connected with a magnetic memory, or the television imagery may be stored on photographic film. The television/photographic film system has been termed phototelevision. The choice of a system of one type or the other is dictated by several considerations, the most important of which are the size and weight characteristics, other conditions being the same (power consumption, reliability, etc.). The advantages and disadvantages of the two systems are discussed and examples are given of types of satellites on which the two types have been employed.

Selivanov, A. S.↗

The possibility of using superconductive systems in the analysis of the composition of cosmic rays

The experimental results on the use of superconductive systems onboard of spacecraft are described. To ensure low temperatures in the cryostat under weightlessness, helium was used at a pressure above the critical pressure. In flight, the temperature was controlled at six points, while the pressure and intensity of the magnetic field were controlled in the solenoids. The methodical test proved it possible to mount special installations on satellites, with extensive magnetic fields based on superconductive alloys, and particularly, low weights and low power consumption magnetic analyzers.

Anashkin, O. P.↗

Laser space rendezvous and docking tradeoff

A spaceborne laser radar (LADAR) was configured to meet the requirements for rendezvous and docking with a cooperative object in synchronous orbit. The LADAR, configurated using existing pulsed CO2 laser technology and a 1980 system technology baseline, is well suited for the envisioned space tug missions. The performance of a family of candidate LADARS was analyzed. Tradeoff studies as a function of size, weight, and power consumption were carried out for maximum ranges of 50, 100, 200, and 300 nautical miles. The investigation supports the original contention that a rendezvous and docking LADAR can be constructed to offer a cost effective and reliable solution to the envisioned space missions. In fact, the CO2 ladar system offers distinct advantages over other candidate systems.

Adelman, S.↗

A review of precision oscillators

Precision oscillators used in PTTI applications include quartz crystal, rubidium gas cell, cesium beam, and hydrogen maser oscillators. A general characterization and comparison of these devices is given including accuracy, stability, environmental sensitivity, size, weight, power consumption, availability and cost. Areas of special concern in practical applications are identified and a projection of future performance specifications is given. An attempt is made to predict physical and performance characteristics of new designs potentially available in the near future.

Hellwig, H.↗

Infrared radiometer for the Pioneer 10 and 11 missions to Jupiter

Pioneer 10 has successfully encountered Jupiter and several of its satellites. The two-channel infrared radiometer used to obtain data relating to thermal properties of the planet and its atmosphere is described. The instrument features a body-fixed, 7.62-cm-diam aperture Cassegrainian telescope with restrahlen filters defining the 14- to 25-micron and 30- to 56-micron bands. Detectors are 88-junction evaporated thin-film thermopiles. Stringent weight constraints of 2 kg dictated all-beryllium construction. Power consumption was 1.2 W.

Bender, M. L.↗

A flight simulator control system using electric torque motors

Control systems are required in flight simulators to provide representative stick and rudder pedal characteristics. A system has been developed that uses electric dc torque motors instead of the more common hydraulic actuators. The torque motor system overcomes certain disadvantages of hydraulic systems, such as high cost, high power consumption, noise, oil leaks, and safety problems. A description of the torque motor system is presented, including both electrical and mechanical design as well as performance characteristics. The system develops forces sufficiently high for most simulations, and is physically small and light enough to be used in most motion-base cockpits.

Musick, R. O.↗

Hybrid measurement chains for the SAS-C spacecraft

Spacecraft electronic systems usually demand tight packaging. It was this consideration which initially forced us to consider hybrid circuits for the analog signal processing circuits in the Small Astronomy Satellite-C (SAS-C) scientific payload. We gradually discovered that increased reliability, low power consumption, and reduced program costs all followed. This paper will attempt to share our laboratory's first experience with hybrid circuits and indicate those areas which we found to be important.

Goeke, R. F.↗

One-millipound mercury ion thruster

A mercury ion thruster has been developed for efficient operation at the nominal 1-mlb thrust level with a specific impulse of about 3,000 sec and a total power consumption of about 120 W. At a beam voltage of 1,200 V and beam current of 72 mA, the discharge chamber operates with a propellant efficiency of 93.8% at an ion-generation energy of 276 eV/ion. The 8-cm diameter thruster advances proven component technology to assure the capability for thruster operation over an accumulated beam-on time in excess of 20,000 hours with a capability for 10,000 on-off duty cycles. Discharge chamber optimization has combined stable current-voltage characteristics with high performance efficiency by careful placement of the discharge cathode near the location of a magnetic-field zero just upstream of the thruster endplate.

Hyman, J., Jr.↗

A multichannel implantable telemetry system for flow, pressure, and ECG measurements

The design, principles of operation, and performance of an implantable miniaturized (48 cu cm in volume) multiplex telemetry system for simultaneous measurement of up to eight physiological parameters (including cardiovascular data) are described. Integrated circuits are used to reduce the size, complexity, and cost of fabrication. Power consumption is reduced using recently developed complementary MOS devices. PWM technique is selected as it is relatively easy to implement, lends itself to ICs, and provides an accurate means of transmitting data. The system is totally implantable within the chest of a test animal, with no wire penetrating through the skin. It is shown that the described system permits repeated measurement of the physiological effects of a variety of interventions in awake unanesthetized animals.

Fryer, T. B.↗

Miniature carbon dioxide sensor

Infrared absorption spectrometer with dual wave length monochromator has several valuable features: 3.4 by 1.6 inch size; accuracy within plus or minus 5% from 0 to 30 mm Hg; instantaneous and temperature-independent response time; negligible O2 and N2 effects and less than 0.5% water vapor effect; 2.5 W power consumption; no moving parts; and 1.5 and 30 mm Hg CO2 in range.

Bordeaux, J.↗

Development of a magnetically suspended momentum wheel

An engineering model of a magnetically suspended momentum wheel was designed, fabricated, and tested under laboratory conditions. The basic unit consisted of two magnet bearings, a sculptured aluminum rotor, brushless dc spin motor, and electronics. The magnet bearings, utilizing rare-earth cobltrat-samarium magnets were active radially and passive axially. The results of the program showed that momentum wheels with magnetic bearings are feasible and operable, and that magnetic bearings of this type are capable of being used for applications where high capacity, high stiffness, and low power consumption are required. The tests performed developed criteria for improved performance for future designs.

Hamilton, S. B.↗

LTA application of a long trailing wire high speed/low weight reeling system

The successful development of a unique yet simple reeling system for handling long trailing tensile members at high speeds is described. This high speed when combined with the system simplicity, low weight and effective motive power consumption make this reeling system particularly attractive to LTA planners and designers for numerous LTA missions.

Werb, D. F.↗

Biomedical ultrasonoscope

An instrument with a single ultrasonic transducer probe and a linear array of transducer probes permitting three operator modes is described. An 'A' and an 'M' mode scanner were combined with a 'C' mode scanner and a single receiver is used. The 'C' scanner mode enables two-dimensional cross sections of the viewed organ. Video-produced markers enable measurement of the dimensions of the heart. COS/MOS integrated logic circuit components are used to minimize power consumption and permit battery operation.

Lee, R. D.↗

Status of Marshall Space Flight Center solar house

The Marshall Space Flight Center (MSFC) solar facility is described herein, and test results obtained from late May 1974 to September 1974 are discussed. This facility was assembled to provide operational experience in the utilization of solar energy for heating and cooling buildings. The major subsystems are the solar collector, the energy storage tank, the simulated living space, the air conditioning and heating subsystems, and the controls. These subsystems are described with emphasis placed on major results and conclusions. A cursory evaluation of the system for cooling is given from energy and power consumption viewpoints. This data evaluation indicates the current system is capable of supplying 50 per cent of the thermal energy required to drive the air conditioner. A preliminary evaluation of winter data indicates that more than 90 per cent of the heating required can be provided by the solar system.

Humphries, W. R.↗