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Results for “FLYBY MISSION”

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 325 records · Page 18
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NASA NTRS1974

Encke ballistic flybys in 1980

In a search for missions with reasonable flyby speed, reasonable arrival conditions, as well as reasonable cost, two types of ballistic trajectories to Encke are studied. The 100-day flight time region is examined, and two trajectories are selected as baseline mission possibilities. To find slower flybys, the 600-day region was investigated as a three-impulse transfer using a simple optimization procedure in order to display the tradeoff between deep space delta-V and flyby speed. Significant lowering of flyby speed is attainable, but the cost in delta-V is so high that this mode does not provide an attractive alternative at present.

Bender, D. F.↗
NASA NTRS1973

Alternate multiple-outer-planet missions using a Saturn-Jupiter flyby sequence

A study has been made of a method for providing more frequent launch opportunities for multiple-planet Grand Tour type missions to the outer solar system. A Saturn-Jupiter flyby sequence was used in the analysis to initiate the mission instead of the normal Jupiter-Saturn sequence. The Saturn-first approach is shown to yield several new launch opportunities following the 1980 cutoff date for Jupiter-first missions. Results are given for various two-planet, three-planet, and four-planet Jupiter-first and Saturn-first missions. A unique five-planet Saturn-first mission and a Saturn-Jupiter flyby which returns to earth are also discussed. Mission performance is evaluated for each flyby technique by comparing Saturn-first and Jupiter-first missions with respect to launch energy requirements, available launch windows, planetary encounter conditions, and total mission times.

Young, J. W.↗
NASA NTRS1992

Exploration of Pluto

Two NASA-sponsored cost-constrained mission implementations for the exploration of Pluto are described. One is the Pluto Fast Flyby (PFF) mission, which utilizes an 83 kg spacecraft to be launched in 1998 aboard a Titan IV (Solid Rocket Motor Upgrade)/Centaur) for an about 7-year-long direct trajectory to Pluto, which will carry an integrated CCD-imaging/UV spectrometer, with a possible integrated IR spectrometer. The other is the Pluto-350 spacecraft, weighing about 316 kg, which will carry a broader instrument set, greater redundancy, and which will require greater than 11 year flight time. Pluto-350 will be launched in 2001 aboard a Delta or Atlas, toward earth and Jupiter swingbys to provide the energy to reach Pluto.

Staehle, Robert L.↗
NASA NTRS1988

Visible and infrared mapping spectrometer (VIMS) - A facility instrument for planetary missions

A second-generation visible and IR mapping spectrometer (VIMS), selected for both the Mars Observer and Comet Rendezvous Asteroid Flyby (CRAF) missions, is described. VIMS is a scanning spectrometer with a focal plane consisting of linear arrays of visible and IR detectors, cooled by a radiative cooler. It is noted that a wide-angle scan using a full-aperture scan mirror was implemented for the Mars Observer; a narrow-angle scan using a scanning secondary mirror within a Cassegrain foreoptic was achieved for the CRAF mission.

Wellman, John B.↗
NASA NTRS1994

Cometary coma chemical composition (C4) mission

Cometary missions are of enormous fundamental importance for many different space science disciplines, including exobiology. Comets are presumed relics of the earliest, most primitive material in the solar nebula and are related to the planetesimals. They undoubtedly provided a general enrichment of volatiles to the inner solar system (contributing to atmospheres and oceans) and may have been key to the origin of life. A Discovery class, comet rendezvous mission, the Cometary Coma Chemical Composition (C4) Mission, was selected for further study by NASA earlier this year. The C4 Mission is a highly focused and usefully-limited subset of the Cometary Rendezvous Asteroid Flyby (CRAF) Mission, concentrating exclusively on measurements which will lead to an understanding of the chemical composition and make-up of the cometary nucleus. The scientific goals of the Cometary Coma Chemical Composition (C4) Mission are to rendezvous with a short-period comet and (1) to determine the elemental, chemical, and isotopic composition of the nucleus and (2) to characterize the chemical and isotopic nature of its atmosphere. Further, it is a goal to obtain preliminary data on the development of the coma (dust and gas composition) as a function of time and orbital position.

Carle, G. C.↗
NASA NTRS1972

Multiple asteroid flyby opportunities in the 1970's and 1980's.

Trajectory characteristics are described for several representative multiple asteroid flyby (MAF) missions possible in the 1970's and early 1980's, many of which are constrained to include a flyby of Ceres, the largest asteroid. It is shown that flybys of three or four asteroids are possible with spacecraft having a delta-V capability of less than 1 km per sec. The major technical problems associated with MAF missions are due to the small size and poorly known orbits of aster oids. These factors make acquisition, guidance, and science measurements difficult, especially for the very small asteroids. Yet, MAF missions are expected to provide a significant increase in knowledge of basic properties of asteroids and to lay the groundwork for more sophisticated rendezvous and sample return missions.

Brooks, D. R.↗
NASA NTRS1994

Cometary Coma Chemical Composition (C4) Mission

Cometary exploration remains of great importance to virtually all of space science. Because comets are presumed to be remnants of the early solar nebula, they are expected to provide fundamental knowledge as to the origin and development of the solar system as well as to be key to understanding of the source of volatiles and even life itself in the inner solar system. Clearly the time for a detailed study of the composition of these apparent messages from the past has come. A comet rendezvous mission, the Cometary Coma Chemical Composition (C4) Mission, is now being studied as a candidate for the new Discovery program. This mission is a highly-focussed and usefully-limited subset of the Cometary Rendezvous Asteroid Flyby (CRAF) Mission. The C4 mission will concentrate on measurements that will produce an understanding of the composition and physical makeup of a cometary nucleus. The core science goals of the C4 mission are 1) to determine the chemical, elemental, and isotopic composition of a cometary nucleus and 2) to characterize the chemical and isotopic nature of its atmosphere. A related goal is to obtain temporal information about the development of the cometary coma as a function of time and orbital position. The four short-period comets -- Tempel 1, Tempel 2, Churyumov-Gerasimenko, and Wirtanen -which all appear to have acceptable dust production rates, were identified as candidate targets. Mission opportunities have been identified beginning as early as 1998. Tempel I with a launch in 1999, however, remains the baseline comet for studies of and planning the C4 mission. The C4 mission incorporates two science instruments and two engineering instruments in the payload to obtain the desired measurements. The science instruments include an advanced version of the Cometary Ice and Dust Experiment (CIDEX), a mini-CIDEX with a sample collection system, an X-ray Fluorescence Spectrometer and a Pyrolysis-Gas Chromatograph, and a simplified version of the Neutral Gas and Ion Mass Spectrometer (NIGMS). Both of these instruments have substantial heritage as they are based on those developed for the CRAF Mission. The engineering instruments include a simplified Comet Dust Environmental Monitor (SCODEM) and a navigational Camera, NAVCAM. While neither of the instruments will be permitted to establish science requirements, it is anticipated that significant science return will be accomplished Radio science will also be included.

Carle, Glenn C.↗
NASA NTRS1987

Navigation of the Mariner Tempel 2 mission - Orbit phase and penetrator deployment

The navigation of the Mariner Mark II spacecraft about the comet Tempel 2 in the Comet Rendezvous Asteroid Flyby (CRAF) mission is described. This mission is the first of a series using the Mariner Mark II spacecraft planned for the 1990's and thereafter. The primary purpose of the mission is to orbit the nucleus of the periodic comet Tempel 2 and study it at close range. A secondary purpose is to fly by and observe one or two asteroids enroute to the comet. During the orbital phase of the mission, a penetrator will be deployed from the spacecraft to impact the surface of the comet and measure the composition and other properties of the nucleus. Navigation accuracies are given in this paper for spacecraft and penetrator trajectory prediction and control. The orbit determination performance in support of science observations while in orbit about the nucleus is also described.

Miller, James K.↗
NASA NTRS1989

Planetary missions

The scientific and engineering aspects of near-term missions for planetary exploration are outlined. The missions include the Voyager Neptune flyby, the Magellan survey of Venus, the Ocean Topography Experiment, the Mars Observer mission, the Galileo Jupiter Orbiter and Probe, the Comet Rendezvous Asteroid Flyby mission, the Mars Rover Sample Return mission, the Cassini mission to Saturn and Titan, and the Daedalus probe to Barnard's star. The spacecraft, scientific goals, and instruments for these missions are noted.

Mclaughlin, William I.↗
NASA NTRS1970

Comet rendezvous missions

Jupiter swingby trajectory analysis for comet flyby and rendezvous missions, discussing approach velocity and payloads

Manning, L. R.↗
NASA NTRS1984

Imaging spectrometer concepts for next-generation planetary missions

In recent years there has been an increasing interest in the imaging spectrometer concept, in which imaging is accomplished in multiple, contiguous spectral bands at typical intervals of 5 to 20 nm. There are two implementations of this concept under consideration for upcoming planetary missions. One is the scanning, or 'whisk-broom' approach, in which each picture element (pixel) of the scene is spectrally dispersed onto a linear array of detectors; the spatial information is provided by a scan mirror in combination with the vehicle motion. The second approach is the 'push-broom' imager, in which a line of pixels from the scene is spectrally dispersed onto a two-dimensional (area-array) detector. In this approach, the scan mirror is eliminated, but the optics and focal plane are more complex. This paper discusses the application of these emerging instrument concepts to the planetary program. Key issues are the trade-off between the two types of imaging spectrometer, the available data rate from a typical planetary mission, and the focal-plane cooling requirements. Specific straw-man conceptual designs for the Mars Geoscience/Climatology Orbiter (MGCO) and the Mariner Mark II Comet Rendezvous/Asteroid Flyby (CRAF) missions are discussed.

Herring, M.↗