Dynamic stability of symmetric spinning missiles.
High drag planetary entry vehicles dynamic stability prediction accounting for gravitational effects in terminal flight at small roll rates
Coakley, T. J.↗
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Role of gravitational stress in land plant evolution - The gravitational factor in lignification Semiannual report
Gravitational effects on lignification in plants
Siegel, S. M.↗
Principles of celestial mechanics
Book on celestial mechanics covering perturbation methods, two body problems, astronomical coordinates, orbital mechanics, satellite rotation, gravitational effects, etc
Fitzpatrick, P. M.↗
The long-term motion of artificial planetary satellites
Artificial planetary satellites long term orbital evolution under strong perturbations, considering solar and lunar gravitational effects
Uphoff, C.↗
Respirometer development program and gravity and neurohypophyseal secretory activity Final technical report
Microrespirometers to measure oxygen consumption of sprouting potato plugs, and gravitational effects on hypothalamo-hypophyseal system of fish
Source record↗
S-band transponder experiment
Apollo 14 command service and lunar module orbital velocity data from radio navigation S-band transponder experiment for lunar gravitation effects
Gottlieb, P.↗
The libration case of the stellar problem of three bodies
Three body stellar problem libration calculation using nonlinear mechanics methods, and application to lunar satellite perturbation by earth and lunar gravitational effects
Fisher, D.↗
Measurement of the gravitational redshift using a clock in an orbiting satellite
A hydrogen maser clock is proposed for enclosure in an orbiting satellite to measure the gravitational effect on time scales with high accuracy. This experiment is used to test the principle of equivalence for clocks in space. Extremely narrow linewidth of Fe-57 radiation and absorption due to Mossbauer effect over 75 ft vertical distance was used to confirm the prediction of the equivalence principle to 1 part in 100. The fractional frequency shift of a satellite-borne oscillator observed from earth is also given.
Vessot, R. F. C.↗
Simple mass distribution for the lunar potential.
A set of twenty-one point masses gravitationally equivalent to the L1 lunar potential model is presented. By construction, the equivalence is valid only in a region of space 'sampled' by Apollo spacecraft. That region is taken to be a finite, torus-shaped shell. When used in place of the L1 model for Apollo 12 lunar orbit determination, the solution set gives spacecraft positions identical to within about 100 m. The solution is developed in two steps: first the L1 potential is examined to determine favorable mass locations, and then the mass values are computed to force an optimum matching of the L1 potential. Therefore the solution set is 'artificial.' It is related to the moon's actual mass distribution only in its similar gravitational effects in a limited region of space.
Levie, S. L., Jr.↗
An analytic guidance technique for planetary and lunar approach trajectories.
An explicit, analytic guidance technique is developed for the hyperbolic approach phases of interplanetary and lunar spacecraft trajectories. The guidance technique is based upon a first-order analytic solution for the perturbed planet-centered (or moon-centered) trajectory. This trajectory is represented as the sum of two components: (1) the unperturbed osculating hyperbola at pericenter, and (2) first-order position and velocity perturbations due to gravitational effects of the sun and other planets. A closed-form analytic approximation for these perturbations valid for the entire approach trajectory is derived, thereby eliminating the need for numerical integration of the equations of motion. By means of this analytic trajectory model, the approach guidance problem is reduced to an equivalent two-body problem. The guidance objectives are specified in terms of actual, attainable conditions at pericenter, and the required corrective velocity is determined explicitly for both fixed and variable times of arrival.
Carlson, N. A.↗
Theory of an experiment in an orbiting space laboratory to determine the gravitational constant.
An experiment is discussed for determining the gravitational constant with the aid of an isolated system consisting of an artificial satellite moving around an artificial planet. The experiment is to be conducted in a spherical laboratory traveling in an orbit around the earth. Difficulties due to the gravity-gradient term are considered, and the three-tunnel method proposed by Wilk (1969) is examined. The rotation of the sphere is discussed together with aspects of the reference systems used, the equations of motion of the spacecraft and of the test objects, the field from the earth's gravity gradient at the test object, higher harmonic terms in the gravity gradient force, gravitational effects of the spacecraft itself, and a computer simulation.
Vinti, J. P.↗
Wicking of liquids in screens
An investigation was conducted to determine the magnitude of the wicking rates of liquids in various screens. Evaluation of the parameters characterizing the wicking process resulted in the development of an expression which defined the wicking velocity in terms of screen and system geometry, liquid properties, and gravitational effects. Experiment data obtained both in normal gravity and in weightlessness demonstrated that the model successfully predicted the functional relation of the liquid properties and the distance from the liquid source to the wicking velocity. Because the pore geometry in the screens was complex, several screen geometric parameters were lumped into a single constant which was determined experimentally for each screen.
Symons, E. P.↗
The gravimetric geodesy investigation
The Gravimetric Geodesy Investigation which will utilize altimeter and satellite-to-satellite tracking data from GEOS-C, ATS-F, and other spacecraft as appropriate to improve our knowledge of the earth's gravitational field is discussed. This investigation is interrelated with the study of oceanographic phenomena such as those associated with tides and currents, hence the latter are considered together with gravitational effects in the analysis of the data. The oceanographic effects, each of the order of a meter or two in amplitude and with still smaller uncertainties does not seriously hamper the altimeter gravimetric studies at the five meter level. Laser and satellite-to-satellite tracking data, when combined with the altimeter results, should provide the basis for such studies over wide areas of the ocean surface. Laser and conventional geodetic tracking data from ISAGEX and succeeding campaigns will provide a valuable framework for these analyses.
Siry, J. W.↗
Space shuttle/food system study. Volume 2, Appendix A: Active heating system-screening analysis. Appendix B: Reconstituted food heating techniques analysis
Technical data are presented which were used to evaluate active heating methods to be incorporated into the space shuttle food system design, and also to evaluate the relative merits and penalties associated with various approaches to the heating of rehydrated food during space flight. Equipment heating candidates were subject to a preliminary screening performed by a selection rationale process which considered the following parameters; (1) gravitational effect; (2) safety; (3) operability; (4) system compatibility; (5) serviceability; (6) crew acceptability; (7) crew time; (8) development risk; and (9) operating cost. A hot air oven, electrically heated food tray, and microwave oven were selected for further consideration and analysis. Passive, semi-active, and active food preparation approaches were also studied in an effort to determine the optimum method for heating rehydrated food. Potential complexity, cost, vehicle impact penalties, and palatability were considered in the analysis. A summary of the study results is provided along with cost estimates for each of the potential sytems
Source record↗
Skylab radar altimeter - Short-wavelength perturbations detected in ocean surface profiles
Short-wavelength anomalies in sea surface topography, caused by the gravitational effects of major ocean bottom topographic features, have been detected by the radar altimeter aboard Skylab. Some features, such as deep ocean trenches, seamounts, and escarpments, displace the ocean surface by as much as 15 meters over 100-kilometer wavelengths. This experiment demonstrates the potential of satellite altimetry for determining the ocean geoid and for mapping major features of the ocean bottom.
Leitao, C. D.↗
A note on the problem of jet stream formation
It is noted that the formation of 'jet streams', or narrow ringlike structures of small particles, in early planetary and satellite systems cannot result solely from inelastic collisions among the small particles. The possibility is considered that gravitational encounters between the particles will perturb them into more eccentric orbits and thus maintain the orbital coupling between particles (or jet streams) in neighboring orbits. It is found that when the gravitational effect of the particles is taken into account, the average eccentricity of the particles increases as agglomeration due to inelastic collisions proceeds. With respect to jet-stream formation, it is suggested that the ever-increasing orbital eccentricity of the particles will aid in coupling together the different 'sub-jet streams', so that large-scale orbital focusing toward the center of the whole system can continue. Alternative mechanisms leading to planetary accretion are briefly discussed.
Ip, W.-H.↗
Making clouds in Spacelab
Improvements in the accuracy of weather predictions and possibilities for changing the weather might depend on a better understanding of the microphysical processes which take place within clouds. A study of these processes on the surface of the earth is difficult in connection with gravitational disturbances. An Atmospheric Cloud Physics Laboratory (ACPL), which is currently being developed, is to be carried into space in the Spacelab in the early 1980's. This facility will provide scientists, for the first time, with the opportunity to study cloud physics without the disturbing gravitational effects. In the ACPL facility, a microscopic element can be suspended without support. The processes of freezing, thawing, collision, electric charging, and temperature changes can be observed and photographed as many times and for as long as necessary.
Duncan, C.↗
Cinemicrographic specimen housing
Housing used to observe gravitation effects on specimens embedded in support media, such as agar, supports microbial specimens vertically for time-lapsed cinemicrographic studies. Procedure cannot be performed with conventional microscopes which see specimens in horizontal plane only.
Wilkins, J. R.↗