Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “mercury”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Sputter erosion and deposition in the discharge chamber of a small mercury ion thruster

A 5 cm diameter mercury ion thruster similar to one tested for 9715 hours was operated approximately 400 hrs each at discharge voltages of 36.6, 39.6, and 42.6 V, with corresponding discharge propellant utilizations of 58, 68, and 70 percent. The observed sputter erosion rates of the internal thruster parts and the anode weight gain rate all rose rapidly with discharge voltage and were roughly in the ratio of 1:3:5 for the three voltages. The combined weight loss of the internal thruster parts nearly balanced the anode weight gain. Hg(+2) ion apparently caused most of the observed erosion.

Power, J. L.↗
NASA NTRS1972

Space food systems - Mercury through Apollo.

Major achievements which characterized the development of food systems used by American astronauts in manned space flight are reviewed throughout a period spanning the Mercury, Gemini, and Apollo programs up to and including the Apollo 11 lunar landing mission. Lists of food types are accompanied by information on packaging, storage, preparation, consumption, and quality of particular products. Experience gained from development efforts for the Manned Orbiting Laboratory Program is also discussed.

Roth, N. G.↗
NASA NTRS1973

Ballistic mode Mercury orbiter missions.

The MVM'73 Mercury flyby mission will initiate exploration of this unique planet. No firm plans for follow-on investigations have materialized due to the difficult performance requirements of the next logical step, an orbiter mission. Previous investigations of ballistic mode flight opportunities have indicated requirements for a Saturn V class launch vehicle. Consequently, most recent effort has been oriented to use of solar electric propulsion. More comprehensive study of the ballistic flight mode utilizing Venus gravity-assist has resulted in identification of timely high-performance mission opportunities compatible with programmed launch vehicles and conventional spacecraft propulsion technologies. A likely candidate for an initial orbiter mission is a 1980 opportunity which offers net orbiter spacecraft mass of about 435 kg with the Titan IIIE/Centaur launch vehicle and single stage solid propulsion for orbit insertion.

Hollenbeck, G. R.↗
NASA NTRS1974

The transit of Mercury of 10 November 1973

The transit of Mercury of November 10, 1973 was observed from Silver Spring, Maryland (76 deg 58' W, 39 deg 01' N) for the period 6:48:00 EST, near sunrise, to 8:17:18 (contact 4). A total of 24 frames of 35mm Pan X film were taken through a Questar telescope equipped with a sun filter of 40mm aperture. The diameter of the solar image is 13mm on the film. Transit photographs from the observation are included.

Feibelman, W. A.↗
NASA NTRS1974

Status of 30 cm mercury ion thruster development

Two engineering model 30-cm ion thrusters were assembled, calibrated, and qualification tested. This paper discusses the thruster design, performance, and power system. Test results include documentation of thrust losses due to doubly charged mercury ions and beam divergence by both direct thrust measurements and beam probes. Diagnostic vibration tests have led to improved designs of the thruster backplate structure, feed system, and harness. Thruster durability is being demonstrated over a thrust range of 97 to 113 mN at a specific impulse of about 2900 seconds. As of August 15, 1974, the thruster has successfully operated for over 4000 hours.

Sovey, J. S.↗
NASA NTRS1974

Seismic effects from major basin formation on the Moon and Mercury

Grooved and hilly terrains are reported which occur at the antipode of major basins on the Moon (Imbrium, Orientale) and Mercury (Caloris). Order-of-magnitude calculations, for an Imbrium-size impact on the Moon, indicate P-wave-induced surface displacements of 10 m at the basin antipode that would arrive prior to secondary ejecta. Comparable surface waves are reported which would arrive subsequent to secondary ejecta impacts and would increase in magnitude as they converge at the antipode. Other seismically induced surface features include: subdued, furrowed crater walls produced by landslides and concomitant secondary impacts; emplacement and leveling of light plains units owing to seismically induced "fluidization" of slide material; knobby, pitted terrain around old basins from enhancement of seismic waves in ancient ejecta blankets; and the production and enhancement of deep-seated fractures that led to the concentration of farside lunar maria in the Apollo-Ingenii region.

Schultz, P. H.↗
NASA NTRS1973

Sputter erosion and deposition in the discharge chamber of a small mercury ion thruster

A 5-cm diameter mercury ion thruster similar to one tested for 9715 hours was operated approximately 400 hrs each at discharge voltages of 36.6, 39.6, and 42.6 V, with corresponding discharge propellant utilizations of 58, 68, and 70 percent. The observed sputter erosion rates of the internal thruster parts and the anode weight gain rate all rose rapidly with discharge voltage and were roughly in the ratio of 1:3:5 for the three voltages. The combined weight loss of the internal thruster parts nearly balanced the anode weight gain. Hg+2 ions apparently caused most of the observed erosion.

Power, J. L.↗
NASA NTRS1974

Surface features on Mercury

A high-resolution study of the surface of Mercury with a 2.388 GHz radar reveals the existence of hills and valleys with heights (depths) of about 1 km. There is also evidence supporting the existence of craters with diameters of about 50 km and depths of about 700 m.

Zohar, S.↗
NASA NTRS1974

Mercury - Does its atmosphere contain water

The atmosphere of Mercury, like that of the moon, is maintained in an extremely tenuous minimum state by weak solar wind accretion and radioactive decay processes, and depleted by strong removal mechanisms. Unlike the moon, it has a high daytime surface temperature that promotes the production of water vapor, which may be the dominant atmospheric constituent derived from solar wind protons.

Thomas, G. E.↗
NASA NTRS1974

Mariner 10 pictures of Mercury - First results

Mercury has a heavily cratered surface containing basins up to at least 1300 kilometers diameter flooded with mare-like material. Many features are closely similar to those on the moon, but significant structural differences exist. Major chemical differentiation before termination of accretion is implied.

Murray, B. C.↗
NASA NTRS1974

The nature of the subsurface of Mercury from microwave observations at several wavelengths

Interferometric observations of Mercury at 3.71 cm are used to determine the dielectric constant of the subsurface material at a depth of 50 cm to be 2.4 plus or minus 0.3. The surface emissivity in the radio range is determined by the value of the dielectric constant which is thus necessary in order to interpret the thermal properties of the regolith. New integrated-disk data at 6- and 18-cm wavelengths are found to be consistent with a regolith of particulate geological material in which radiative transfer of heat is important. The results are very similar to the lunar case where regolith density, dielectric constant, and loss tangent are observed to increase smoothly with depth in the subsurface.

Cuzzi, J. N.↗
NASA NTRS1974

Mariner 10 Mercury encounter

Mariner 10's closest approach to Mercury on Mar. 29, 1974 occurred on the dark side of the planet at a range of approximately 700 kilometers. The spacecraft trajectory passed through the shadows of both the sun and earth. Experiments conducted included magnetic fields, plasma and charged particle studies of the solar wind interaction region, television photography, extreme ultraviolet spectroscopy of the atmosphere, the detection of infrared thermal radiation from the surface, and a dual-frequency radio occultation in search of an ionosphere.

Dunne, J. A.↗
NASA NTRS1974

Magnetic field observations near Mercury - Preliminary results from Mariner 10

Results are presented from a preliminary analysis of data obtained near Mercury on Mar. 29, 1974 by the NASA-GSFC magnetic field experiment on Mariner 10. Rather unexpectedly, a very well-developed, detached bow shock wave, which develops as the super-Alfvenic solar wind interacts with the planet, has been observed. In addition, a magnetosphere-like region, with maximum field strength of 98 gammas at closest approach (704 kilometers altitude), has been observed, contained within boundaries similar to the terrestrial magnetopause. The obstacle deflecting the solar wind flow is global in size, but the origin of the enhanced magnetic field has not yet been uniquely established. The field may be intrinsic to the planet and distorted by interaction with the solar wind.

Ness, N. F.↗
NASA NTRS1974

Electrons and protons accelerated in Mercury's magnetic field

Fluxes of protons with energies of about 550 kev and electrons with energies of about 300 kev which exceed approximately 10,000 and 100,000 per sq cm per sec, respectively, have been discovered in the magnetosphere of Mercury. Electron fluxes greater than 1000 per sq cm per sec are also observed in the outbound pass of the Mariner 10 spacecraft through the magnetosheath. The intensity vs time profiles of the particle fluxes in the magnetosphere appear with sudden onsets beginning at interplanetary background levels and persisting for times equivalent to their being distributed spatially over regions having a scale size comparable to the planetary radius. It is shown that the radiation events observed in the magnetosphere and magnetosheath are transient and are not interpretable in terms of stable trapped particle populations.

Simpson, J. A.↗
NASA NTRS1974

Navigation of the Mariner 10 spacecraft to Venus and Mercury

Orbit determination techniques used during the highly successful flight of Mariner 10 to Venus and Mercury are presented. Comparisons are made between different data sets, different sets of parameters, and between a conventional least squares batch filter and a sequential batch filter and smoother that was designed for this mission. The sequential filter was able to account for small spacecraft forces that the batch filter was unable to handle effectively, and hence, contributed greatly to the mission success. The sequential filter and smoother design is given as well as results for each phase of the mission.-

Christensen, C. S.↗
NASA NTRS1959

Preliminary Study of Capsule Recovery for the First Series of Project Mercury Orbital Flights

This report contains the results of a preliminary study of the search and. recovery operations required. for the safe and. expeditious return of the Mercury Recovery Capsule in the first series of orbital flights. The study is concerned primarily with the high-probability impact areas in the Atlantic Ocean. Emphasis is placed on safe recovery within reasonable time at least cost. A preliminary study of this nature is not able to provide final answers to all of the problems; the report instead constitutes a "first look" at the overall operation. Much of the report is therefore devoted to basic data, the building blocks from which recovery systems can be assembled and evaluated. These include the performance characteristics, reliability, and cost of the vehicles and equipment which may be used, and their compatibility with one another, with the capsule, and with the expected environment. The availability of vehicles and equipment has also been considered., although it is appreciated. that this may change from week to week where the forces are drawn from the military services. consideration of alternative vehicles, equipments, and systems, and their evaluation from the standpoint of effectiveness and. cost. While the equipment considered. is generally expected to be operational throughout 1960, consideration is also given to more advanced schemes which might effect reductions in recovery time, cost, or dependence upon the military forces.

Source record↗
NASA NTRS1975

Finite element analysis of Mercury slosh in the solar electric propulsion stage

The static equilibrium shapes of the neoprene bladder have been established corresponding to various ullage and gravity configurations under specified boundary conditions. The hemispherical bladder is taken to be attached at the diametral plane of the sphere with zero relative slope. With these shapes, the spherical tank with bladder and mercury has been modeled as an assemblage of finite elements. The properties of these elements have then been calculated using a linear displacement field. The dynamic characteristics were obtained to be used to define a mechanical analog which will reproduce the sloshing phenomenon of the system.

Singh, J. N.↗
NASA NTRS1975

Measurement of sputtered efflux from 5-, 8-, and 30-cm diameter mercury ion thrusters

A study was undertaken to investigate the sputtered efflux from 5-, 8-, and 30-cm diameter mercury ion thrusters. Quartz crystal microbalances and fused silica samples were used to analyze the sputtered flux. Spectral transmittance measurements and spectrographic analysis of the samples were made after they were exposed to different thruster effluence by operating the thrusters at various conditions and durations of time. These measurements were used to locate the source of the efflux and determine its accumulated effect at various locations near the thruster. Comparisons of in situ and ex situ transmittance measurements of samples exposed to thruster efflux are also presented.

Weigand, A. J.↗