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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Laser range measurement for a satellite navigation scheme and mid-range path selection and obstacle avoidance

The functions of a laser rangefinder on board an autonomous Martian roving vehicle are discussed. The functions are: (1) navigation by means of a passive satellite and (2) mid-range path selection and obstacle avoidance. The feasibility of using a laser to make the necessary range measurements is explored and a preliminary design is presented. The two uses of the rangefinder dictate widely different operating parameters making it impossible to use the same system for both functions.

Zuraski, G. D.↗
NASA NTRS1971

Performance of the Boeing LRV wheels in a lunar soil simulant. Report 2: Effects of speed, Wheel load, and soil

Two nearly identical Boeing-GM wire-mesh Lunar Roving Vehicle (LRV) wheels were laboratory tested in a lunar soil simulant to determine the influence of wheel speed and acceleration, wheel load, presence of a fender, travel direction, and soil strength on the wheel performance. Constant-slip and three types of programmed-slip tests were conducted with a single-wheel dynamometer system. Test results indicated that performance of single LRV wheels in terms of pull coefficient, power number, and efficiency were not influenced by wheel speed and acceleration, travel direction, the presence of a fender, or wheel load. Of these variables, only load influenced sinkage, which increased with increasing load. For a given slip, the pull coefficient and power number increased with increasing soil strength. However, for a given pull coefficient or slope, slip was less in firmer soil; thus, the power number decreased and efficiency increased with increasing soil strength.

Melzer, K.↗
NASA NTRS1972

Apollo 16 time and motion study

A time and motion study is presented of astronaut lunar surface activity on Apollo 16 which consists of five distinct analyses: an evaluation of lunar mobility, a comparison of task performance in 1-g training and lunar EVA, a study of metabolic costs and adaptation, a discussion of falls, and retrieval of fallen objects. Two basic mobility patterns, the hop or canter and the traditional walking gait, were consistently utilized in longer traverses. The metabolic rates associated with these two mobility types, each used by a different astronaut, were relatively equivalent. The time to perform tasks on the lunar surface was significantly longer (on the order of 70%) than the time to perform the same tasks during the last 1-g training session. These results corroborated the findings on Apollo 15 and were not significantly different from them. There was general improvement in lunar EVA performance upon repetition of tasks. Metabolic rate (BTU/hr.) and metabolic cost (BTU) decreased over successive EVAs. Specifically, the metabolic rate associated with riding the lunar roving vehicle (LRV) decreased by approximately 18% from EVA 1 to EVA 2 and by 15% from EVA 2 to EVA 3.

Kubis, J. F.↗
NASA NTRS1972

The lunar cart

Expanded experiment-carrying capability, to be used between the Apollo 11 capability and the lunar roving vehicle capability, was defined for the lunar surface crewmen. Methods used on earth to satisfy similar requirements were studied. A two-wheeled cart was built and tested to expected mission requirements and environments. The vehicle was used successfully on Apollo 14.

Miller, G. C.↗
NASA NTRS1972

Ground-Commanded Television Assembly (GCTA)

A ground-commanded color television assembly (GCTA) was designed for use on lunar explorations associated with NASA manned Apollo missions. The camera system as seen on Apollo 15 provided television coverage in the vicinity of the lunar module (LM) landing site, and was mounted on the lunar roving vehicle (LRV) to provide color coverage of astronaut activity and lunar topography during traverses on the surface. Remote control of the camera from earth was accomplished through the existing real-time Apollo command links. The assembly is illustrated. The configuration satisfied all anticipated requirements of the Apollo 15 mission and was fully responsive to specifications. The technical approach was based on proven designs and offered maximum mission flexibility, potential growth, and capability to withstand environmental extremes encountered on the lunar surface.

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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.

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NASA NTRS1972

Soil mechanics

Preliminary results are presented of an investigation of the physical and mechanical properties of lunar soil on the Descartes slopes, and the Cayley Plains in the vicinity of the LM for Apollo 16. The soil mechanics data were derived form (1) crew commentary and debriefings, (2) television, (3) lunar surface photography, (4) performance data and observations of interactions between soil and lunar roving vehicle, (5) drive-tube and deep drill samples, (6) sample characteristics, and (7) measurements using the SRP. The general characteristics, stratigraphy and variability are described along with the core samples, penetrometer test results, density, porosity and strength.

Mitchell, J. K.↗
NASA NTRS1973

Surface electrical properties experiment study phase, volume 1

The evolution of a conceptual design of the flight hardware for the surface electrical properties experiment (SEP), the definition of requests for proposals, the analysis of proposals submitted by prospective flight hardware subcontractors, and recommendations for the flight configuration to be implemented are discussed. Initial efforts were made to assess the electromagnetic environment of the SEP experiment. An EMI receiver and tri-loop antenna were constructed and tests of opportunity were performed with a lunar roving vehicle (LRV). Initial analyses were made of data from these tests with support from this contract, analyses which were continued in depth under the hardware contract.

Meyer, J. W.↗
NASA NTRS1973

Apollo 17 mission. Lunar roving vehicle/traverse gravimeter experiment motion sensitivity

The results of the lunar roving vehicle/traverse gravimeter experiment motion sensitivity test shows that the gravity measurements in both the normal and bypass modes should not be adversely affected by motion induced in the lunar roving vehicle by operation of the television camera position drive device or the operation of the surface electrical properties receiver/recorder. Motion of the traverse gravimeter experiment occurred when a 1.4-hertz resonant mode in pitch of the pallet was excited. Both of these modes were excited by camera elevation changes with the camera axis positioned fore and aft.

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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.

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NASA NTRS1973

Very long baseline interferometry

S-band stations with dual tracking capability have been used to gather double differential very long baseline interferometry data on Apollo 16 and Apollo 17. This was accomplished by simultaneously receiving both monochromatic radio signal emissions at each of two separated receiving stations, transmitting these data to a central processing facility, and calculating the differences between Doppler angular rates to determine the motion of the lunar roving vehicle.

Salzberg, I. M.↗
NASA NTRS1973

Lunar and planetary rover concepts.

Roving vehicle systems and concepts which evolved from lunar mission and mission studies, as well as from Martian mission studies, are discussed. Additional planetary mission applications for rovers and other remotely manned systems are briefly described. These mission include such targets as Venus, the natural satellites of some planets, and selected asteroids.

Moore, J. W.↗
NASA NTRS1973

Unmanned surface traverses of Mars and Moon: Science objectives, payloads, operations

Science objectives and properties to be measured are outlined for long surface traverse missions on Mars and the Moon, with remotely-controlled roving vehicles. A series of candidate rover payloads is proposed for each planet, varying in weight, cost, purpose, and development needed. The smallest weighs 35 kg; the largest almost 300 kg. A high degree of internal control will be needed on the Mars rover, including the ability to carry out complex science sequences. Decision-making by humans in the Mars mission includes supervisory control of rover operations and selection of features and samples of geological and biological interest. For the lunar mission, less control on the rover and more on earth is appropriate. Science portions of the rover mission profile are outlined, with timelines and mileage breakdowns. Operational problem areas for Mars include control, communications, data storage, night operations, and the mission operations system. For the moon, science data storage on the rover would be unnecessary and control much simpler.

Jaffe, L. D.↗
NASA NTRS1973

Apollo 17 site selection

The scientific arguments and recommendations concerning the selection of the Apollo 17 landing site are presented. The final selection was influenced by the accomplishments and circumstances of previous Apollo flights and by the proposed experiments for Apollo 17. The decisive factors in selecting the Taurus-Littrow landing area were: (1) certainty of acquiring highlands lunar samples, (2) superior orbital coverage, and (3) better use of the lunar roving vehicle capabilities.

Hinners, N. W.↗
NASA NTRS1974

Viking '79 Rover study. Volume 1: Summary report

The results of a study to define a roving vehicle suitable for inclusion in a 1979 Viking mission to Mars are presented. The study focused exclusively on the 1979 mission incorporating a rover that would be stowed on and deployed from a modified Viking lander. The overall objective of the study was to define a baseline rover, the lander/rover interfaces, a mission operations concept, and a rover development program compatible with the 1979 launch opportunity. During the study, numerous options at the rover system and subsystem levels were examined and a baseline configuration was selected. Launch vehicle, orbiter, and lander performance capabilities were examined to ensure that the baseline rover could be transported to Mars using minimum-modified Viking '75 hardware and designs.

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NASA NTRS1974

Composition dependent effects in gas chromatography

Fundamantal concepts are developed which are required to optimize a gas chromatograph-mass spectrometer chemical analysis system suitable for use on an unmanned roving vehicle for Mars exploration. Prior efforts have developed simulation models for the chromatograph which were compared with data obtained from a test facility. Representation of binary systems by superposition was shown to be a first-order approximation and in certain cases large discrepencies were noted. This subtask has as its objective generation of additional binary data and analysis of the observed nonlinear effects.

Lavoie, R. C.↗
NASA NTRS1974

Analysis of chromatograph systems using orthogonal collocation

Research is generating fundamental engineering design techniques and concepts for the chromatographic separator of a chemical analysis system for an unmanned, Martian roving vehicle. A chromatograph model is developed which incorporates previously neglected transport mechanisms. The numerical technique of orthogonal collocation is studied. To establish the utility of the method, three models of increasing complexity are considered, the latter two being limiting cases of the derived model: (1) a simple, diffusion-convection model; (2) a rate of adsorption limited, inter-intraparticle model; and (3) an inter-intraparticle model with negligible mass transfer resistance.

Woodrow, P. T.↗
NASA NTRS1974

Recognition of three dimensional obstacles by an edge detection scheme

The need for an obstacle detection system on the Mars roving vehicle was assumed, and a practical scheme was investigated and simulated. The principal sensing device on this vehicle was taken to be a laser range finder. Both existing and original algorithms, ending with thresholding operations, were used to obtain the outlines of obstacles from the raw data of this laser scan. A theoretical analysis was carried out to show how proper value of threshold may be chosen. Computer simulations considered various mid-range boulders, for which the scheme was quite successful. The extension to other types of obstacles, such as craters, was considered. The special problems of bottom edge detection and scanning procedure are discussed.

Reed, M. A.↗