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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 1,747 records · Page 97
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NASA NTRS1979

Pointing and control of planetary spacecraft - The next 20 years

The preliminary pointing and control systems for five planetary mission groups are presented, as well as the rationale and key characteristics for each system type. The five groups entail: (1) a preliminary survey, (2) a detailed remote observation, (3) close scrutiny in deep space, (4) close scrutiny near the sun, and (5) a sample return. Attention is given to each group with respect to two- and three-axis control and various instruments for spin control. The future development of component trends and needs, electronic trends, electromechanical development, gyros and other general system trends are discussed in detail.

Mcglinchey, L. F.↗
NASA NTRS1980

Planetary spacecraft pointing and control - The next 20 years

Pointing and control systems recommended for NASA planetary exploration missions of the next twenty years are discussed. The functional and operational requirements and design constraints imposed on the driving control system by the mission and science goals of the spacecraft are examined. Criteria for the selection of a pointing and control system type (spin, dual-spin, three-axis active or momentum bias) are outlined, including payload functional characteristics, orbital characteristics, vehicle configuration and mission duration, and candidate system types proposed for preliminary survey, detailed remote observation, deep space close scrutiny, near-sun close scrutiny and sample return missions are indicated. Trends in control system design are discussed, and key enabling technology areas that will require additional or new development are considered, with particular emphasis on laser and fiber optics gyros, CCD arrays and DMA signal/power transmission, bearings and motor technologies, directed at three-axis active and dual-spin implementations.

Mcglinchey, L. F.↗
NASA NTRS1980

Laboratory verification of the lunar orbital X-ray fluorescence experiment - Initial results

The combined use of remote sensing and returned sample chemical data in lunar studies presumes a direct link between the two types of data. Laboratory experiments have demonstrated that within the precision of the lunar orbital X-ray fluorescence data there is a direct relationship between the fluorescence K-series X-radiation emitted from Mg, Al and Si in the surfaces of lunar soil samples and the concentrations of these elements in the bulk soil samples. This relationship encompasses both mare and terra soils. The degree of maturity is not an important variable for the existing orbital X-ray data. It is argued that these results are directly applicable to the lunar surface analyzed by the Apollo orbital X-ray fluorescence experiment.

Hubbard, N.↗
NASA NTRS1981

Aerobraking techniques for planetary missions

Aerobraking techniques are applied to trajectory design for the VOIR (Venus Orbiting Imaging Radar) mission to enhance overall mission performance. The approach can be used for other planetary missions such as a Titan orbiter or a Mars sample return to earth. The orientation of the elliptical insertion orbit must be chosen in such a way that the combined effects of solar gravity, central-body harmonics, and drag on periapsis altitude are minimized to avoid frequent maneuvers. The selection of the base and width of a corridor for periapsis altitude depends upon the temperature and integrated heat of the aerobrake shield, the atmospheric density profile, the duration of aerobraking, the number of maneuvers, the time available between maneuvers, and uncertainties in the central-body gravity field and atmospheric density. Flight path profiles for an aerodynamically stable spacecraft and an inertially fixed spacecraft passing through the free molecular flow regime, as well as the transitional flow regime, are illustrated

Tang, C. C. H.↗
NASA NTRS1981

Interplanetary navigation in the 1980's and 1990's

Interplanetary space missions for the 1980's and 1990's will require more accurate and more automated navigation than the missions of the 1970's have required. Spacecraft which have orbited Mars and Venus, landed on Mars, and flown past Jupiter and Saturn are giving way to spacecraft which may orbit Jupiter, Saturn, Uranus, and Neptune, fly past Pluto, fly by or rendezvous with comets and asteroids, return samples from Mars, and fly close to the sun. Starting with the Voyager navigation system as a baseline, anticipated navigation requirements and performance for some of these candidate future missions are discussed, along with navigation system designs and strategies. Various developments in navigation technology, required or desirable for these missions, are treated.

Wood, L. J.↗
NASA NTRS1981

Optimization of extended propulsion time nuclear-electric propulsion trajectories

This paper presents the methodology used in optimizing extended propulsion time NEP missions considering realistic thruster lifetime constraints. These missions consist of a powered spiral escape from a 700-km circular orbit at the earth, followed by a powered heliocentric transfer with an optimized coast phase, and terminating in a spiral capture phase at the target planet. This analysis is most applicable to those missions with very high energy requirements such as outer planet orbiter missions or sample return missions where the total propulsion time could greatly exceed the expected lifetime of an individual thruster. This methodology has been applied to the investigation of NEP missions to the outer planets where examples are presented of both constrained and optimized trajectories.

Sauer, C. G., Jr.↗
NASA NTRS1981

A proposed new policy for planetary protection

A critical review of the present policy was conducted with emphasis on its application to future planetary exploration. The probable impact of recent data on the implementation of the present policy was also assessed. The existing policy and its implementation were found to: be excessive for certain missions (e.g., Voyager), neglect the contamination hazard posed by the bulk constituent organics of spacecraft, be ambiguous for certain missions (e.g., Pioneer Venus), and treat all extraterrestrial sample return missions alike. The major features of the proposed policy are planet/mission combinations, a qualitative top level statement, and implementation by exception rather than rule. The concept of planet/mission categories permits the imposition of requirements according to both biological interest in the target planet and the relative contamination hazard of the mission type.

Barengoltz, J. B.↗
NASA NTRS1981

Orbiting Quarantine Facility. The Antaeus report, summary

Requirements for handling extraterrestrial samples in an orbiting quarantine facility are examined. The major concepts and findings of the study are outlined. One approach that could be taken for receiving, containing, and analyzing samples returned from the surface of Mars in a mission analogous to the lunar return missions of the late 1960s and early 1970s is described. It constructs a general mission scenario and presents an overall systems design, including an approach to cost assessment. Particular attention is paid to the design of system hardware components and to the elaboration of an experimental protocol.

Source record↗
NASA NTRS1982

Rusty rock 66095 - A paradigm for volatile-element mobility in highland rocks

The ultimate goals of Apollo 16 consortia investigations are related to a determination of the nature of the early crust of the moon, taking into account questions regarding the petrogenesis of highland breccias and melt-rocks. In addition to these potential objectives, the consortia study of 66095 has also the goal to provide information for an understanding of the origin of volatile elements. Since 66095 is the most volatile-rich sample returned by the Apollo missions and its elemental ratios mimic those in many Apollo 16 breccias, it was selected as a paradigm for the highland breccias. 66095 is a clast-laden, impact-melt breccia. The volatile-rich nature is manifest in the presence of rust, schreibersite, and minor volatile-bearing compounds, usually in association with native metal and/or troilite. Attention is given to aspects of petrography, mineral chemistry, major element chemistry, the volatile bearing phases, and the history of the volatiles starting with their ultimate origin.

Hunter, R. H.↗
NASA NTRS1982

Mariner Mark II - An approach to solar system exploration in the 1990's

Significant progress has been made in the twenty-plus years since the start of direct solar system exploration. NASA through its Solar System Exploration Committee (SSEC), has been developing guidelines and plans for continuing this exploration. The Mariner Mark II (MMII) development project has been initiated as one element of this planning to focus primarily on imaging class, deep space missions at minimum cost. A description is presented of concepts for a new spacecraft and ground system capability, uniquely focused on the selected mission scenarios and lower cost approaches of MMII. A summary of Mariner Mark II candidate missions is provided, taking into account a comet rendezvous, a comet elemental sample return, main-belt asteroid flybys and rendezvous, a Saturn orbiter, Titan or Saturn flyby and probe, Uranus flyby and probe, Neptune flyby and probe, and a Mars Orbiter.

Heacock, R. L.↗
NASA NTRS1982

Earth-crossing asteroids - New discoveries

An earth-crossing asteroid is an asteroid whose orbit will intersect the orbit of the earth as a result of secular perturbations. Astronomical observations have led to the discovery of 43 earth-crossing asteroids during the last fifty years. Nearly sixty percent of these were found in the decade 1971-1981. Noteworthy results of the last decade are discussed, taking into account the Aten asteroids, accidental rediscoveries, asteroids of possible cometary origin, candidates for rendezvous and sample return missions, and populations and collision rates with earth. The observed earth-crossing asteroids are listed in a table, and the orbits of earth, Mars, and four Atens projected on ecliptic plane are shown.

Helin, E. F.↗
NASA NTRS1983

Mariner Mark II and the exploration of the solar system

NASA's Solar System Exploration Committee has proposed the Mariner Mark II concept for the next generation of deep-space planetary observation missions, which will yield Voyager- and Galileo-quality focused data sets at a fraction of the costs associated with those spacecraft. Cost-limiting strategies under consideration include the use of reconfigurable designs, a multimission ground support system, and the incorporation of such selected new technologies as an all-X band telemetry system, fiber-optic rate sensors for use as an inertial reference system, image compression, and electronic and optical disk data distribution. It is believed possible to meet cost goals of 150-300 million/mission. The missions under consideration are comet rendezvous and sample return, main belt asteroid flybys, and orbits, flybys and probes of Saturn, Titan, Neptune and Uranus.

Neugebauer, M.↗
NASA NTRS1983

A proposed new policy for planetary protection

A policy on the protection of extraterrestrial bodies from contamination by terrestrial microorganisms and organic constituents that might interfere with studies of chemical and biological evolution on those bodies is proposed which is based on new information gained in planetary exploration over the past decade. The proposed policy overcomes the difficulties associated with the uncertainties in parameters and the rigid requirements of the current probabilistic approach by eliminating the general quantitative guideline and by calling for the implementation of planetary protection procedures for space projects by exception, depending on target planet and type of encounter. The impact of the proposed policy on the implementation of future space missions is illustrated for the Galileo Jupiter mission, a cometary mission, the Saturn Orbiter with Twin Probes, and a Mars Surface Sample Return Mission, and procedures which may lead to the eventual adoption of the policy are noted.

Devincenzi, D. L.↗
NASA NTRS1983

Mars - A contamination potential?

Three regions on Mars, Solis Lacus, Noachis-Hellespontus, and the Syrtis Major border areas, would appear to have generally less hostile environments than at the Viking lander sites. Significant soil moisture may extend to within about 1 cm of the surface. Water vapor pressures within the pore spaces may be near saturation, and brines may be physically segregated from pockets of relatively pure H2O. Temperatures reach above 0 C during southern spring and summer, with peak temperatures reaching +22 C. These regions should contain fewer oxidants, and primary synthesis of organics may occur. The potential for contamination of these sites by microbes transported from existing spacecraft should be assessed. The adequacy of proposed new planetary protection procedures for possible future United States Mars Surface Sample Return missions should also be assessed in light of these findings.

Huguenin, R. L.↗
NASA NTRS1984

The energy dependence and surface morphology of Kapton (trademark) degradation under atomic oxygen bombardment

Data from laboratory simulations and from samples returned from STS-8 are used to derive the energy dependence of the mass loss rate of Kapton under atomic oxygen bombardment and to discuss the development of surface structure and its effect on erosion rates. It is concluded that all the laboratory data from discharge and flow tubes and from accelerated beams, along with the orbital data from STS-3 through STS-8, can be accommodated by a rate of mass loss that varies with impact energy normal to the surface. It is hypothesized that increases of mass loss rate with exposure time may be due to trapping of the incoming atoms by the surface structure which develops.

Ferguson, D. C.↗
NASA NTRS1984

The discovery of 1982 DB, the most accessible asteroid known

A small Apollo object was found while photographing the split comet DuToit 2-Hartley on February 27/28, 1982. Designated 1982 DB, this earth-crossing asteroid passed the earth at a distance of 4.08 million km about 1 month prior to its discovery. Asteroid 1982 DB has been determined to be the most accessible near-earth minor planet known. It provides many excellent opportunities for rendezvous and sample return missions, and a rare dual rendezvous mission with 1980 AA as the second target. For a mission to be realized, opportunities to observe 1982 DB during future apparitions must be taken.

Helin, E. F.↗
NASA NTRS1984

Space exploration outlook

The exploration of the solar system has been one of NASA's most significant achievements. Currently Voyager 2 is on its way to Uranus and Neptune, and Galileo is being readied for detailed investigation of Jupiter and its Galilean satellites. A new phase of exploration will be inaugurated in the mid-80s with the start of the Planetary Observers and Mariner Mark II missions. A major thrust during this phase will be to cut mission costs by emphasizing spacecraft inheritance and multi-mission automated mission operations. More ambitious missions, e.g., Mars Sample Return, are under study but probably will not be candidates for new start funding till the mid-90s. Another exciting area is the potential utilization of resources on the moon and near earth asteroids.

Rea, D. G.↗
NASA NTRS1984

The Planetary Observer Program

An overview is presented of NASA's plans for the Planetary Observer Program, whose key element is to control the cost of each mission while establishing a long-term, stable base for the planetary sciences. The SSEC (Solar System Exploration Committee) has endorsed the view that many high science priority inner solar system missions are possible through the use of spacecraft derived from existing earth-orbital spacecraft. It has also recommended the application of space hardware such as that used on the Voyager and Galileo missions, development of both a new modular spacecraft for outer planet, comet, and main-belt asteroid missions (Mariner Mark II Program), and a multi-mission operations system to support future missions after the Venus Radar Mapper (VRM), and Galileo. A set of missions for the SSEC's Core Program has been recommended; they include: the VRM, the Mars Geoscience/Climatology Observer, the Comet Rendezvous/Asteroid Flyby, the Lunar Geoscience Orbiter, the Near-Earth Asteroid Rendezvous, the Venus Atmosphere Probe, the Mars Aeronomy Orbiter, the Mars Surface Probe, and the Comet Intercept Sample Return.

Blume, W. H.↗