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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 1,423 records · Page 79
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

The magnetic attitude control of the Atmosphere Explorer-E spacecraft

The Atmosphere Explorer-E spacecraft was launched in November 1975, as the last of the Atmosphere Explorer series. It is a dual spin satellite and has on-board magnetic coils to maintain the spin axis of the spacecraft within 2 degrees of orbit normal. There is a constraint on the total angular momentum to keep it at a constant level, at around 1200 in-lb-sec +/-10 percent. On the previous AE satellites, the attitude and momentum were controlled separately, with dipoles mounted parallel to the spin axis for pure attitude control, and with coils in the spin plane to desaturate the momentum wheel. Due to the near-equatorial orbit of the AE-E spacecraft, spin axis coils would be inefficient, because the dipoles would have been closely aligned with the geomagnetic field vector. For this reason it was decided to control both attitude and momentum magnitude with dipoles in the spin plane. However, for spin plane coils the attitude and momentum control are strongly coupled, which required a special control theory to be worked out.

Grell, M. G.↗
NASA NTRS1978

A study to examine the feasibility of using surface penetrators for mineral exploration

The feasibility of using penetrators in earth applications is examined. Penetrator applications in exploration for mineral resources only is summarized. Instrumentation for future penetrators is described. Portions of this report are incorporated into a more extensive report examining other penetrator applications in exploration for fossil fuels, geothermal resources, and in environmental and engineering problems, which is to be published as a NASA technical publication.

Davis, A. S.↗
NASA NTRS1979

Study of entry and landing probes for exploration of Titan

Saturn's largest moon, Titan, is a totally unique planetary body which is certain to yield exciting new phenomena. Current information is lacking in detail to distinguish between a thin methane rich atmosphere and a thick nitrogen rich atmosphere. Therefore, both the thin and thick atmospheric models were used for the study of various Titan probe classes described in this report. The technical requirements, conceptual design, science return, schedule, cost and mission implications of three probe classes that could be used for exploration of Titan are defined. The three probe classes were based on a wide range of exploration mission possibilities.

Source record↗
NASA NTRS1979

International Ultraviolet Explorer (IUE) Post Launch Report 2

The International Ultraviolet Explorer (IUE), an Explorer class ultraviolet astronomy mission, is an international cooperative program between the United States, the United Kingdom (UK), and the European Space Agency (ESA) which provides for a single launch into geosynchronous orbit to conduct spectral distribution studies of celestial and solar system ultraviolet sources. The spacecraft and scientific instruments were designed and fabricated at the Goddard Space Flight Center. The spectrograph camera was provided by the UK; ESA provided the solar array as well as the European ground station. The IUE observatory system was designed to functionally resemble a ground-based optical observatory at which guest observers could execute observing programs in real time. Observatory performance substantially exceeded design and mission objectives. The secondary mission objectives were also met.

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NASA NTRS1979

Solar Mesosphere Explorer optical-mechanical systems engineering

Mission overview of the Solar Mesosphere Explorer is presented along with design analysis and summaries of results. The Solar Mesosphere Explorer is a spin stabilized satellite carrying a complement of four Ebert-Fastie spectrometers and a four-channel Mersenne radiometer. Description of the spectrometer is given including a telescope and its aberrations. The radiometer is also described with consideration given to isothermal and thermal design, a Winston paraboloid, and optical tolerances. These five instruments are for measuring the earth's ozone density and distribution and providing quantitative data about those processes which govern the formation and destruction of ozone.

Gause, K. A.↗
NASA NTRS1979

Scientific exploration of the moon

The paper reviews efforts undertaken to explore the moon and the results obtained, noting that such efforts have involved a successful interdisciplinary approach to solving a number of scientific problems. Attention is given to the interactions of astronomers, cartographers, geologists, geochemists, geophysicists, physicists, mathematicians and engineers. Earth based remote sensing and unmanned spacecraft such as the Ranger and Surveyor programs are discussed. Emphasis is given to the manned Apollo missions and the results obtained. Finally, the information gathered by these missions is reviewed with regards to how it has increased understanding of the moon, and future exploration is considered.

El-Baz, F.↗
NASA NTRS1979

Future exploration of the asteroids

Future possibilities for the further study of the asteroids are reviewed, with particular attention paid to space missions for their direct exploration. The role of traditional ground-based and earth orbiting techniques is examined briefly, and it is concluded that although astronomical techniques are presently at their peak, and despite the opportunities provided by the Infrared Astronomical satellite, the Space Telescope and Spacelab Infrared Telescope Facility, the next major step will require direct exploration by space probes to obtain information on asteroid surface chemistry, geology and bulk properties. Various mission modes and propulsion systems for a first multi-target asteroid mission are discussed, including flyby, rendezvous, landing and sample return, and ion-drive propulsion systems. Science payloads for a basic rendezvous mission are considered, and target selection for multi-asteroid flyby tours and rendezvous tours is discussed. Consideration is also given to sample return missions for the evaluation of the asteroid as potential resources.

Morrison, D.↗
NASA NTRS1981

Dynamics Explorer twin spacecraft under evaluation tests

The Dynamics Explorer A and B satellites designed to explore the interactive processes occuring between the magnetosphere and Earth's ionosphere, upper atmosphere, and plasmasphere are described. Effects of these interactions, satellite orbits, data collecting antennas, solar power systems, axes, configurations, and Earth based command, control and data display systems are mentioned.

Redmond, C.↗
NASA NTRS1981

NASA launches dual Dynamics Explorer spacecraft

A Delta launch vehicle was used to insert Dynamics Explorer A into a highly elliptical polar orbit, ranging from 675 to 24,945 km, and Dynamics Explorer B satellite into a low polar orbit, ranging from 306 to 1,300 km. The two spacecraft are designed to provide specific knowledge about the interaction of energy, electric currents, electric fields, and plasmas between the magnetosphere, the ionosphere, and the atmosphere.

Source record↗
NASA NTRS1981

Deep space exploration - The new challenges

Prospects for future planetary exploration missions are examined. The evolution of planetary mission objectives in the U.S. and U.S.S.R. is traced, and planetary mission attempts and results are reviewed. The present situation with regard to planetary and interplanetary spacecraft operating in 1980 and approved deep-space missions for the future is considered, and the good scientific prospects of future Soviet missions are emphasized. Future plans for U.S. missions not yet approved are then discussed, with consideration given to the Venus Orbital Imaging Radar mission, a mission to Halley's comet, a rendezvous with a short-period comet, a Saturn orbiter mission with probes into Saturn and Titan, asteroid missions, gravity-assisted flights to Uranus, Neptune and Pluto, a Mercury orbiter/lander, lunar activities and a program of Mars exploration. The demanding requirements in the fields of automation, instrumentation and data gathering techniques, launch vehicle capabilities and spacecraft propulsion for future possible missions and possible solutions are examined. Finally, recommendations for the simultaneous pursuit of both major missions at the scientific and technological frontier and lesser missions designed to investigate specific scientific questions raised by earlier probes are presented.

French, J. R.↗
NASA NTRS1981

An evaluation of nuclear electric propulsion for planetary exploration missions

A set of nuclear electric propulsion (NEP) system parameters for planetary exploration missions is described. Orbiter missions to the planets Saturn, Uranus and Neptune were selected for assessment, and five delivery modes were evaluated. The NEP system envisioned for this application consisted of a nuclear fission reactor with a thermoelectric conversion system and a thrust subsystem comprised of power processors coupled with mercury ion-bombardment thrusters. The results indicate that an NEP system sized at 90-160 kW electrical power rating and operating within a specific impulse range of 4500-5500 sec provides adequate performance for outer planet exploration.

Nagorski, R. P.↗
NASA NTRS1981

Nuclear Electric Propulsion - A concept for solar system exploration

The potential of Nuclear Electric Propulsion (NEP) to meet the increasing demands of our planetary space exploration program is examined and evaluated. Based on an assumption of a modest growth beyond current technology, an NEP system is described that provides performance advantage over all competitive technologies. Flight times and available payload mass - as indicators of mission performance - are compared for several mission opportunities of interest. NEP is shown to have a unique capacity for substantial reductions in mission flight times in terms of payloads consistent with the needs of planetary exploration.

Nagorski, R. P.↗
NASA NTRS1981

The stellar coronal X-ray Explorer: STCOEX

The status of the newly born field of stellar X-ray astronomy is considered. The need for further observational capability, the study of stellar surface activity and the development of design criteria for a follow-up mission, with primary emphasis on stellar observations and with general capabilities within the scope of the Explorer program are examined. The criteria which lead to the desired instrumental capabilities are reviewed; and an overview of the proposed instrument and some of its capabilities, as indicated by simulations is presented. Two versions of a trial payload the stellar coronal. Explorer (STCOEX) which meet the observational desirable are developed.

Vaiana, G. S.↗
NASA NTRS1981

The Fabry-Perot Interferometer on Dynamics Explorer

The Fabry-Perot Interferometer (FPI) on Dynamics Explorer is a remote sensing instrument designed to measure the temperature, meridional wind and density of the metastable atoms O(1S) and O(1D), and the ion O(plus)(2P) in the thermosphere. The measurements are made with a stable, high resolution Fabry-Perot etalon, which performs a wavelength analysis on the light detected from the thermospheric emission features by spatially scanning the interference fringe plane with a multichannel array detector. The wavelength analysis characterizes the Doppler line profile of the emitting species. A sequential altitude scan, performed by a commandable horizon scan mirror, provides a cross-sectional view of the thermodynamic and dynamic state of the thermosphere below the orbit of the Dynamics Explorer B satellite.

Hays, P. B.↗
NASA NTRS1981

High-Altitude Plasma Instrument for Dynamics Explorer-A

The Dynamics Explorer A High-Altitude Plasma Instrument (HAPI) will make differential measurements of the velocity-space distributions of electrons and positive ions over the energy/charge range of 5 eV to 32 keV. Five identical analyzers, each making simultaneous measurements of electrons and positive ions at 64 possible energy levels, will have viewing angles of 45, 78, 90, 102, and 135 deg relative to the spacecraft spin axis. The HAPI data will contribute to the overall Dynamics Explorer science objectives, particularly by providing information on the hot-plasma effects of the coupling of energy, mass, and momentum within the earth's atmosphere, ionosphere, and magnetosphere.

Burch, J. L.↗
NASA NTRS1981

Dynamics Explorer Science Data Processing System

The Dynamics Explorer project has acquired the ground data processing system from the Atmosphere Explorer project to provide a central computer facility for the data processing, data management and data analysis activities of the investigators. Access to this system is via remote terminals at the investigators' facilities, which provide ready access to the data sets derived from groups of instruments on both spacecraft. The original system has been upgraded with both new hardware and enhanced software systems. These new systems include color and grey scale graphics terminals, an augmentation computer, micrographics facility, a versatile data base with a directory and data management system, and graphics display software packages.

Smith, P. H.↗
NASA NTRS1982

High-temperature electronics applications in space exploration

One of the most exciting applications of high-temperature electronics is related to the exploration of the planet Venus. On this planet the atmospheric temperatures range from about 170 K at elevations of 100 km to a searing 730 K near the surface. Mechanisms for exploring the atmosphere might include balloons, airplanes, surface landers, and surface-launched probes. Balloons, for example, could fly in the region from 20 (320 C at 22 bars) to 60 km (-20 C at 0.2 bar). Suitable balloon fabrics presently exclude excursions to lower altitudes; however, adequate electronic systems could survive to 325 C. Small airplanes would require more sophisticated electronics for guidance and control. Long life surface landers would most likely be developed first, as these could be used to measure long-term variations in weather. Ranging transponders would be important for ephemeris development, measurement of spin state, and studies of general relativity. Surface temperatures of 460 C and pressures of 90 bars present a challenge to the developers of such instruments. Other space applications for high-temperature electronics include transponders for the surface of Mercury, near solar drag-free orbiters, and deep atmospheric penetrators for Jupiter and Saturn. Each of these has its own particular problems with respect to instrumentation adequate to meet the desired scientific goals. This paper is primarily concerned with defining possible mission applications, the required electronic systems, and the approaches that are currently being studied for their development.

Jurgens, R. F.↗
NASA NTRS1982

Analytical solution for the drift behavior of Dynamics Explorer-B

The Dynamics Explorer (DE) mission was designed to explore the earth's magnetosphere, ionosphere, and plasmasphere. The DE mission employs two spacecraft, including DE-A and DE-B. The spacecraft were launched from the Western Test Range on Aug. 3, 1981, onboard the same Delta launch vehicle. The two spacecraft were placed in a coplanar polar orbit, with DE-A in a high altitude orbit (perigee = 570 km and apogee = 23174 km) and DE-B in a low altitude orbit (perigee = 309 km and apogee = 1013 km). In the present investigation, an attempt has been made to validate the flight data for DE-B with analytic and simulation results. The external torques acting on the spacecraft are represented in terms of tractable mathematical functions. A piecewise linear model of the superrotation of the upper atmosphere is assumed. The effect of individual torques on the long-term pitch axis motion is investigated using analytic and simulation methods. The results are found to be in very good agreement with the available flight data.

Sellappan, R. G.↗