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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Lessons learned from selecting and testing spaceflight potentiometers

A solar array drive (SAD) was designed for operation on the TOPEX/POSEIDON spacecraft that was launched in August, 1992. The experience gained in selecting, specifying, testing to failure, and redesigning its position sensor produced valuable lessons for future component selection and qualification. Issues of spaceflight heritage, cost/benefit/risk assessment, and component specification are addressed. It was found that costly schedule and budget overruns may have been avoided if the capability of the candidate sensors to meet requirements had been more critically examined prior to freezing the design. The use of engineering models and early qualification tests is also recommended.

Iskenderian, T.↗
NASA NTRS1994

Lessons Learned form Selecting and Testing Spaceflight Potentiometers

A solar array drive (SAD) was designed for operation on the TOPEX/POSEIDON spacecraft that was launched in August of 1992. The experience gained in selecting, specifying, testing to failure, and redesigning its position sensor produced valuable lessons for future component selection and qualification.

TOPEX/POSEIDON redesigning SAD component specifica↗
NASA NTRS1974

Measuring probe position recorder

A device which enables a person to record the location of measurements made by a hand held nonconducting probe is described. The hand probe is coupled to a linear potentiometer and a sine-cosine potentiometer by means that varies the output of the linear potentiometer proportional to the distance between the hand probe and the linear potentiometer and that varies the output of the sine-cosine potentiometer proportional to the angular movement of the hand probe relative to the sine-cosine potentiometer. The output of the linear potentiometer is applied directly to one input of the sine-cosine potentiometer and is applied through an inverter to the other input or the sine-cosine potentiometer. The cosine and sine outputs of the sine-cosine potentiometer are applied to the X and Y outputs, respectively, of an X-Y recorder.

Flagge, B.↗
NASA NTRS1980

Active notch filter network with variable notch depth, width and frequency

An active notch filter having independently adjustable notch frequency, width, and depth is provided by three equal capacitors connected in series with an operational amplifier (connected in a voltage follower configuration), a potentiometer across the series connected capacitors for notch depth adjustment, and a potentiometer (for notch frequency connected across the center capacitor); with its tap connected to receive a voltage feedback signal from a variable voltage divider comprised of another potentiometer for notch width. Adjusting the voltage dividing potentiometer will independently set the notch width, and adjusting the tap on the potentiometer across the center capacitor will independently adjust the notch frequency of the filter. A second operational amplifier connected in a voltage follower configuration may be used to connect the voltage divider output to the adjustable tap of the potentiometer across the center capacitor.

Black, J. M.↗
NASA NTRS1982

Pressure suit joint analyzer

A measurement system for simultaneously measuring torque and angular flexure in a pressure suit joint is described. One end of a joint under test is held rigid. A torque transducer is pivotably supported on the other movable end of a joint. A potentiometer is attached to the transducer by an arm. The wiper shaft of the potentiometer is gripped by a reference arm that rotates the wiper shaft the same angle as the flexure of joint. A signal is generated by the potentiometer which is representative of the joint flexure. A compensation circuit converts the output of the transducer to a signal representative of joint torque.

Vykukal, H. C.↗
NASA NTRS1993

Instrumented Glove Measures Positions Of Fingers

Glove instrumented with flat membrane potentiometers to obtain crude measurements of relative positions of fingers. Resistance of each potentiometer varies with position of associated finger; translator circuit connected to each potentiometer converts analog reading to 1 of 10 digital levels. Digitized outputs from all fingers fed to indicating, recording, and/or data-processing equipment. Gloves and circuits intended for use in biomedical research, training in critical manual tasks, and other specialized applications.

Bozeman, Richard J., Jr.↗
NASA NTRS1989

Method and apparatus for multiplexing switch signals

Apparatus for multiplexing switch state signals comprises a plurality of switches and parallel weighted resistors connected in series between circuit ground and a node at a utilization device. The resistors are weighted as a function of a power of the same base, such as the power of the base 2, for coding the multiplexed switch state signals. A constant current source connected between the node and circuit ground drives current over a single cable conductor through the resistor. Each switch may be independently closed to change the switch state voltage signals multiplexed to the node. An analog-to-digital converter connected between the node and circuit ground demultiplexes the switch state signals received at the node and provides a switch state signal at each analog-to-digital output corresponding to the state of the switches at the moment. A potentiometer may replace a resistor and bypass switch combination in a position where the potentiometer has a maximum value of the lowest power of the base in order to multiplex a true analog voltage signal while switch state signals are unambiguously coded and multiplexed. The potentiometer in the least significant position permits the analog value to be in the range from 0 to a maximum corresponding to the least significant position of the switch state encoding. The invention may be used in redundancy systems by duplicating the invention with corresponding switches in each duplication ganged to open and close simultaneously upon operation of a pushbutton switch.

Hannaford, Blake↗
NASA NTRS1973

Apollo 16 mission anomaly report no. 10: Rear steering inoperative

The report by the Apollo 16 crew that the lunar roving vehicle rear steering was inoperative during the initial drive from the vehicle's deployment site was investigated. The malfunction, and the steering system are described. It is concluded that an open circuit occurred either in the hand controller potentiometer or between the potentiometer wiper and the summing node.

Source record↗
NASA NTRS1973

Rear Steering Inoperative: Apollo 16 Mission

The inoperative condition of the rear steering system of the lunar roving vehicle (Apollo 16) during the initial drive to the modular equipment stowage assembly was investigated. The front and rear steering systems are described, and the failure analyzed. It is concluded that an open circuit must have occurred either in the hand controller potentiometer or between the potentiometer wiper and the summing node.

Source record↗
NASA NTRS1980

Air speed and attitude probe

An air speed and attitude probe characterized by a pivot shaft normally projected from a data boom and supported thereby for rotation about an axis of rotation coincident with the longitudinal axis of the shaft is described. The probe is a tubular body supported for angular displacement about the axis of rotation and has a fin mounted on the body for maintaining one end of the body in facing relation with relative wind and has a pair of transducers mounted in the body for providing intelligence indicative of total pressure and static pressure for use in determining air speed. A stack of potentiometers coupled with the shaft to provide intelligence indicative of aircraft attitude, and circuitry connecting the transducers and potentiometers to suitable telemetry circuits are described.

Baker, G. J.↗
NASA NTRS1984

Spectrophone stabilized laser with line center offset frequency control

Continuous offset tuning of a frequency stabilized CW gas laser is achieved by using a spectrophone filled with the same gas as the laser for sensing a dither modulation, detecting a first or second derivative of the spectrophone output with a lock-in amplifier, the detected output of which is integrated, and applying the integrator output as a correction signal through a circuit which adds to the dither signal from an oscillator a dc offset that is adjusted with a potentiometer to a frequency offset from the absorption line center of the gas, but within the spectral linewidth of the gas. Tuning about that offset frequency is achieved by adding a dc value to the detected output of the dither modulation before integration using a potentiometer.

Kavaya, M. J.↗
NASA NTRS1984

Load positioning system with gravity compensation

A load positioning system with gravity compensation has a servomotor, position sensing feedback potentiometer and velocity sensing tachometer in a conventional closed loop servo arrangement to cause a lead screw and a ball nut to vertically position a load. Gravity compensating components comprise the DC motor, gears, which couple torque from the motor to the lead screw, and constant current power supply. The constant weight of the load applied to the lead screw via the ball nut tend to cause the lead screw to rotate, the constant torque of which is opposed by the constant torque produced by the motor when fed from the constant current source. The constant current is preset as required by the potentiometer to effect equilibration of the load which thereby enables the positioning servomotor to see the load as weightless under both static and dynamic conditions. Positioning acceleration and velocity performance are therefore symmetrical.

Hollow, R. H.↗
NASA NTRS1991

Device Measures Angle Of Deployment

Simple electromechanical device indicates angular position of unfolding panel during and after deployment. Resistance of potentiometer gradually increases as unfolding of solar panel about hinge moves wiper of potentiometer. At full deployment, panel pushes and opens normally closed switch. Designed for use on panel of solar photovoltaic cells in spacecraft, modified for use in other, similar position-indicating applications.

Jermakian, Joel B.↗
NASA NTRS1992

Eliminating Deadbands In Resistive Angle Sensors

Proposed shaft-angle-measuring circuit provides continuous indication of angle of rotation from 0 degree to 360 degrees. Sensing elements are two continuous-rotation potentiometers, and associated circuitry eliminates deadband that occurs when wiper contact of potentiometer crosses end contacts near 0 degree position of circular resistive element. Used in valve-position indicator or similar device in which long operating life and high angular precision not required.

Salomon, Phil M.↗
NASA NTRS2012

Dynamically variable spot size laser system

A Dynamically Variable Spot Size (DVSS) laser system for bonding metal components includes an elongated housing containing a light entry aperture coupled to a laser beam transmission cable and a light exit aperture. A plurality of lenses contained within the housing focus a laser beam from the light entry aperture through the light exit aperture. The lenses may be dynamically adjusted to vary the spot size of the laser. A plurality of interoperable safety devices, including a manually depressible interlock switch, an internal proximity sensor, a remotely operated potentiometer, a remotely activated toggle and a power supply interlock, prevent activation of the laser and DVSS laser system if each safety device does not provide a closed circuit. The remotely operated potentiometer also provides continuous variability in laser energy output.

Gradl, Paul R.↗
NASA NTRS1965

Tension is servo controlled in film advance system

Servocontrol device feeds film into a roller system. Two linear potentiometers connected to spring loaded tension rollers furnish servo input signal. Can be used in any continuous material transport system.

Source record↗
NASA NTRS1965

Simple circuit reduces transistor switching time

Silicon-Controlled Rectifier /SCR/, gated by a voltage divider, controls the potentiometer in transistorized switching circuits. The SCR acts as a gate to trigger the switching transistor only when the input signal reaches an amplitude that will switch the transistor rapidly.

Source record↗
NASA NTRS1966

High voltage potential divider calibrated by simple device

Resistance bridge device incorporates a potentiometer, switches, and a null detector to calibrate high potential dividers under high voltage operation conditions. Calibration can be performed with this device in less than 1 minute at an accuracy of 0.001 percent.

Lewis, R. N.↗