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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Extended performance solar electric propulsion thrust system study. Volume 1: Executive summary

Several thrust system design concepts were evaluated and compared using the specifications of the most advanced 30 cm engineering model thruster as the technology base. The extensions in thruster performance required for the Halley's comet mission were defined and alternative thrust system concepts were designed. Confirmation testing and analysis of thruster and power-processing components were performed, and the feasibility of satisfying extended performance requirements was verified. A baseline design was selected from the alternatives considered, and the design analysis and documentation were refined. A program development plan was formulated that outlines the work structure considered necessary for developing, qualifying, and fabricating the flight hardware for the baseline thrust system within the time frame of a project to rendezvous with Halley's comet. An assessment was made of the costs and risks associated with a baseline thrust system as provided to the mission project under this plan. Critical procurements and interfaces were identified and defined. Results are presented.

Poeschel, R. L.↗
NASA NTRS1989

Orbit determination of the Comet Rendezvous/Asteroid Flyby mission - Post-rendezvous phases

Orbit determination during the post-rendezvous phases of the Comet Rendezvous/Asteroid Flyby mission is described. The orbit determination process is discussed, with emphasis placed on optical imaging of landmarks and Doppler tracking. Rotational dynamics are introduced for the cometary nucleus. State estimation errors are given for spacecraft trajectory prediction and cometary nucleus attitude prediction. Estimation errors are also given for parameters that describe the cometary nucleus such as moments of inertia and gravity harmonics. The orbit determination performance in support of science observations while in orbit about the nucleus is described.

Miller, James K.↗
NASA NTRS1981

Interactions between a spacecraft and an ion thruster produced environment

The electron bombardment ion thruster is a candidate propulsion device for several proposed interplanetary missions. A comet rendezvous mission is expected to be the first use of a Solar Electric Propulsion System (SEPS). Because this is the first use of such a system, it is necessary to understand the interactions between the spacecraft and the environment produced by the SEPS. A preliminary assessment of the interactions between a thruster produced environment and the Comet Rendezvous spacecraft, including its science instruments, is presented which concludes that compatibility between the SEPS and the spacecraft can be obtained.

Carruth, M. R., Jr.↗
NASA NTRS1971

Interplanetary mission planning

A long range plan for solar system exploration is presented. The subjects discussed are: (1) science payload for first Jupiter orbiters, (2) Mercury orbiter mission study, (3) preliminary analysis of Uranus/Neptune entry probes for Grand Tour Missions, (4) comet rendezvous mission study, (5) a survey of interstellar missions, (6) a survey of candidate missions to explore rings of Saturn, and (7) preliminary analysis of Venus orbit radar missions.

Source record↗
NASA NTRS1981

Comets: Gases, ices, grains and plasma

The program and abstracts of the 97 papers delivered at the colloquium are presented. Cometary nuclei, comet dust, the coma, ion tails, several comet missions, and cometary origin and evolution were discussed.

Wilkening, L. L.↗
NASA NTRS1982

A scheme for tracking and pointing at small celestial bodies during high velocity encounters

A scheme has been developed and verified for closed-loop tracking and pointing space-borne science instruments at small celestial bodies, such as comets and asteroids, during high velocity encounters. To overcome ephemeris uncertainties for these bodies, the scheme involves sequential estimation of flyby model parameters. The design consists of a two-axis gimballed platform mounted on a three-axis stabilized spacecraft. A platform-mounted optical tracker provides closed-loop target measurements and precision micro-step actuators enable high-rate platform slewing. For comet missions which involve dust particle impact disturbances, a dual-mode attitude control scheme is presented for minimizing transient response time.

Burdick, G. M.↗
NASA NTRS1982

An instrument for rapidly measuring plasma distribution functions with high resolution

An instrument which can rapidly measure plasma particle distribution functions has been developed based upon recent innovations in electrostatic analyzer design and position sensitive particle detection. The new analyzer uses a quadrispherical geometry, but has a completely uniform 360 deg fan-shaped field of view. The polar angular distribution of entering particles is spatially imaged onto a position sensitive detector at the annular exit aperture after a deflection through 90 deg. Several methods of position sensitive detection have been successfully used in conjunction with this analyzer. The simplest is individual channel multipliers spaced around the annular exit. Microchannel plate electron multipliers permit greater position resolution to be obtained, and a detector using microchannel plates followed by a resistive anode image converter obtains angular resolution of about one degree, i.e., 360 individual angle pixels. Instruments of this type were flown on a sounding rocket in early 1982 and will be included on the Giotto comet mission and the AMPTE ion release module (IRM).

Carlson, C. W.↗
NASA NTRS1982

Structural load prediction methods for space payloads

The state of the art in structural loads prediction procedures for spacecraft is summarized. Three categories of prediction techniques delineated by cost, complexity, comprehensiveness, accuracy, and applications are outlined. The lowest cost method has been used for earth resources, communications, and weather satellites, the medium cost method for sun-synchronous orbits and the large space telescope, and the most expensive for planetary missions, comet rendezvous, and out-of-ecliptic orbits, all assuming Shuttle launch. The lowest cost method involves a mass-acceleration curve. A shock spectra technique predicts a least upper bound for loads. A recovered transient method analyzes the interface acceleration of two connected launch vehicles. The most accurate method devised thus far is a transient analysis of the total launch vehicle/payload dynamic system.

Wada, B. K.↗
NASA NTRS1986

Hungarian space research 1981-1985: Lectures and review articles

This monograph presents an overview of Hungarian space research from 1981 to 1985. Topics discussed in the original report include the development of space research centers, the flight of the first Hungarian astronaut, Hungarian participation in international space programs such as the Vega/Halley's Comet mission and the BEALUCA materials science experiment, advances in astronomical research, and activities of the Cosmic Geodetic Observatory. Other topics discussed incude space biomedical studies, meteorological applications of space research, satellite communications, and satellite power supply systems.

Benko, G.↗
NASA NTRS1989

Multi-spacecraft testing of time-dependent interplanetary MHD models for operational forecasting of geomagnetic storms

An MHD 2-1/2D, time-dependent model is used, together with observations of six solar flares during February 3-7, 1986, to demonstrate global, large-scale, compound disturbances in the solar wind over a wide range of heliolongitudes. This scenario is one that is likely to occur many times during the cruise, possibly even encounter, phases of the Multi-Comet Mission. It is suggested that a model such as this one should be tested with multi-spacecraft data (such as the MCM and earth-based probes) with several goals in view: (1) utility of the model for operational real-time forecasting of geomagnetic storms, and (2) scientific interpretation of certain forms of cometary activities and their possible association with solar-generated activity.

Dryer, M.↗
NASA NTRS1991

Systems for COMET

The Centers for Commercial Development of Space (CCDS) have become the nation's primary focus for stimulating private sector investment in space. In establishing the COMmercial Experiment Transporter (COMET) program, the CCDS's have taken a major step toward the full scale commercial development of space. The COMET program will enable the CCDS community to turn the goal of commercial space into reality, and in the process, establish U.S. leadership in the global market for space systems and services. Some details are presented on the systems that make up the COMET missions, specifically as they describe the accommodation for potential users and mission parameters.

Andrews, Harry↗
NASA NTRS2005

Planetary Exploration in ESA

A viewgraph presentation on planetary exploration in the European Space Agency is shown. The topics include: 1) History of the Solar System Material; 2) ROSETTA: The Comet Mission; 3) A New Name For The Lander: PHILAE; 4) The Rosetta Mission; 5) Lander: Design Characteristics; 6) SMART-1 Mission; 7) MARS Express VENUS Express; 8) Planetary Exploration in ESA The Future.

Schwehm, Gerhard H.↗
NASA NTRS2014

The Meteoroid Fluence at Mars Due to Comet Siding Spring

Long-period comet C/2013 A1 (Siding Spring) is headed for a close encounter with Mars on 2014 Oct 19. A collision between the comet and the planet has been ruled out, but the comets coma may envelop Mars and its man-made satellites. We present an analytic model of the dust component of cometary comae that describes the spatial distribution of cometary dust and meteoroids and their size distribution. If the coma reaches Mars, we estimate a total incident particle fluence on the planet and its satellites of 0.01 particles per square meter. We compare our model with numerical simulations, data from past comet missions, and recent Siding Spring observations.

Moorhead, Althea V.↗
NASA NTRS1977

Opportunities for ballistic missions to Halley's comet

Alternative strategies for ballistic missions to Halley's comet in 1985-86 are described. A large scientific return would be acquired from a ballistic Halley intercept in spite of the high flyby speeds that are associated with this mission mode. The possibility of retargeting the cometary spacecraft to additional comets after the Halley intercept also exists. Two cometary spacecraft of identical design would be used to carry out four separate cometary encounters over a 3 year period. One spacecraft would intercept Halley's comet before its perihelion passage in December 1985 and then go on to comet Borrelly with an encounter in January 1988. The other spacecraft would be targeted for a postperihelion Halley intercept in March 1986 before proceeding toward an encounter with comet Tempel 2 in September 1988.

Farquhar, R. W.↗
NASA NTRS1977

Opportunities for ballistic missions to Halley's comet

Alternative strategies for ballistic missions to Halley's comet in 1985-86 are described. It is shown that a large science return would be acquired from a ballistic Halley intercept in spite of the high flyby speeds of almost 60 km/sec that are associated with this mission mode. The possibility of retargeting the cometary spacecraft to additional comets after the Halley intercept also exists. In one scenario two cometary spacecraft of identical design would be used to carry out four separate cometary encounters over a three-year period. One spacecraft would intercept Halley before its perihelion passage in December 1985 and then go on to comet Borrelly witn an encounter in January 1988. The other spacecraft would be targeted for a post-perihelion Halley intercept in March 1986 before proceeding towards an encounter with comet Tempel-2 in September 1988. The flyby speeds for the Borrelly and Tempel-2 intercepts are 21 and 13 km/sec, respectively.

Farquhar, R. W.↗
NASA NTRS1991

The comet rendezvous asteroid flyby mission: A status report

The Comet Rendezvous Asteroid Flyby (CRAF) mission received a new start in fiscal year 1990. CRAF will match orbits with an active short-period comet and follow it around the Sun, making scientific measurements of the nucleus, coma, and tail. The Imaging system will map the nucleus surface at a resolution of 1 meter/line-pair or better, while Visible and Infrared Mapping Spectrometer (VIMS) and Thermal Infrared Radiometer Experiment (TIREX) will produce spectral and thermal maps of the surface. Onboard instruments will collect cometary dust, ice, and gases and perform elemental and molecular analysis. A suite of fields and particles instruments will observe the solar wind interaction with the cometary atmosphere and tail. Radio tracking of the spacecraft will provide an accurate measure of the nucleus mass and higher harmonics in the comet's gravity field. En route to the comet, the spacecraft will make a close flyby of a large asteroid, preferably a primitive type from the outer main belt. Observations at the asteroid include remote sensing mapping of the surface, detection of any solar wind interaction observable at the flyby distance, and measurement of the asteroid mass to better than 10 percent accuracy. Detailed design of the CRAF spacecraft is currently underway at the Jet Propulsion Laboratory (JPL). Recent mass growth has necessitated a switch to Venus-Earth gravity assist type trajectories, similar to that used by the Galileo spacecraft. These trajectories require longer flight times from launch to rendezvous with the target comet. The details of the current baseline mission, spacecraft design, and instrument payload will be reviewed.

Weissman, Paul R.↗
NASA NTRS1973

Study of 1980 Comet Encke-asteroid missions using a spin-stabilized spacecraft. Volume 2: Technical Report

The data and analyses that support the conclusions and recommendations of a space mission to intercept comets and asteroids are presented. The scientific basis for the Encke missions is discussed and includes a summary of the physical characteristics of Encke, a statement of scientific objectives and priorities, a definition of the spacecraft payload, and a rationale for utilization and instrumentation of coma probes. Data are included for the reference mission selected as the baseline for science analysis and design studies. Alternate spacecraft configurations are compared in terms of their capability in meeting the science and mission requirements.

Bursnall, W. J.↗