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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS2014

The Orbit of Transneptunian Binary Manwe and Thorondor and Their Upcoming Mutual Events

A new Hubble Space Telescope observation of the 7:4 resonant transneptunian binary system (385446) Manwe has shown that, of two previously reported solutions for the orbit of its satellite Thorondor, the prograde one is correct. The orbit has a period of 110.18 +/- 0.02 days, semimajor axis of 6670 +/- 40 km, and an eccentricity of 0.563 +/- 0.007. It will be viewable edge-on from the inner Solar System during 2015- 2017, presenting opportunities to observe mutual occultation and eclipse events. However, the number of observable events will be small, owing to the long orbital period and expected small sizes of the bodies relative to their separation. This paper presents predictions for events observable from Earth-based telescopes and discusses the associated uncertainties and challenges.

Hubble Space Telescope observations↗
NASA NTRS1966

Algal mutualism

Symbiosis between unicellular algae and marine invertebrates

ALGAE↗
NASA NTRS1972

Magnetic circuitry mutual coupling probe

Development of magnetic probe for nondestructive testing of multilayer printed circuit boards to determine existence of opens or shorts is reported. Components of probe are described and procedures for operation are discussed. Two illustrations are provided to show magnetic circuits and principles of operation.

Anthony, P. L.↗
NASA NTRS1975

Mutual assistance in space

Operating principles, system functions, and technological problems associated with developing compatible spacecraft, station approach, and docking facilities between the U.S. and the U.S.S.R. are reported. Two designs, the probe cone and the androgynous docking device are examined.

Bushuev, K.↗
NASA NTRS1978

Mutual phenomena of Jupiter's five inner satellites in 1979

In this paper, we first predict eclipses and occultations of the Galilean satellites in 1979 and find that, although circumstances are generally poor, about 75 events are observable. We have then made a special point of including 40 eclipses of J5 (Amalthea) by the Galilean satellites in the hope that both visual and far-infrared light curves can be obtained - the former giving accurate astrometric information for J5, and the latter possible bearing on its surface structure or composition.

Aksnes, K.↗
NASA NTRS1979

Definition of mutually optimum NDI and proof test criteria for 2219 aluminum pressure vessels. Volume 1: Methods

The requirements for proof testing and nondestructive inspection of aluminum pressure vessels were discussed. The following conclusions are (1) lack-of-fusion weld defects are sufficiently tight in the as-welded condition to be considered undetectable; (2) proof-level loads are required to fully open lack-of-fusion weld defects; (3) significant crack opening occurs at subproof levels so that an inspection enhancement loading treatment designed to avoid catastrophic failure is feasible; (4) currently used proof levels for 2219 pressure vessels are adequate for postproof inspection; (5) quantification of defect size and location using collimated ultrasonic pitch-catch techniques appears sufficiently feasible for tankage to warrant developmental work; (6) for short-time single-cycle pressure-vessel applications, postproof inspection is desirable; and (7) for long-term multiple-cycle pressure-vessel applications, postproof inspection is essential for life assurance.

Schwartzberg, F. R.↗
NASA NTRS1979

Definition of Mutually Optimum NDI and Proof Test Criteria for 2219 Aluminum Pressure Vessels. Volume 2: Optimization and Fracture Studies

Certain behavioral aspects associated with fracture and crack extension that cannot be studied using other techniques were evaluated with the ultrasonic method. Characterization of collimated beam techniques showed that significant beam width reduction could be accomplished. Techniques for collimation are given. The crack-opening displacement-gage correction-factor study showed that displacement resulting from crack opening and that from plasticity could be readily differentiated. Crack closure studies using both ultrasonic and crack-opening displacement measurements showed an opening and closing behavior associated with load-unload curves. The results of this work were in general agreement with the closure concepts of Elber. Ultrasonic measurements used to study the nature of flaw extension characteristics associated with failure of the ligament between the flaw front and back surface showed that penetration could occur by an abrupt fracturing after subcritical growth or by continuous growth.

Schwartzberg, F. R.↗
NASA NTRS1979

Definition of mutually optimum NDI and proof test criteria for 2219 aluminum pressure vessels. Volume 3: Applications to rail defect evaluation

The technique for inspection of railroad rails containing transverse fissure defects was discussed. Both pulse-echo and pitch-catch inspection techniques were used. The pulse-echo technique results suggest that a multiple-scan approach using varying angles of inclination, three-surface scanning, and dual-direction traversing may offer promise of characterization of transverse defects. Because each scan is likely to produce a reflection indicating only a portion of the defect, summing of the individual reflections must be used to obtain a reasonably complete characterization of the defect. The ability of the collimated pitch-catch technique to detect relatively small amounts of flaw growth was shown. The method has a problem in characterizing the portions of the defect near the top surface or web intersection. The work performed was a preliminary evaluation of the prospects for automated mapping of rail flaws.

Schwartzberg, F. R.↗
NASA NTRS1983

Delay line and mutual coupling considerations for MST radar antenna arrays

Basic antenna theory which states that the field radiated from an antenna array is equal to the sum of the currents flowing in each element of the array is discussed. The feedline distribution system guarantees the proper amplitude and phase of the current for each element of an array. The difference in electrical lengths of the feedlines to the elements has to equal the desired phase angle. The current for voltage delay in a transmission line is equal to the transmission line electrical length in only a few special cases, when the transmission line is terminated in its characteristic impedance or when the transmission line's electrical length is a multiple of 90 degrees.

Brosnahan, J. W.↗