Trajectory and propulsion characteristics of comet rendezvous opportunities
Trajectory and propulsion characteristics of spacecraft rendezvous mission opportunities to comets during 1975 to 1995
Friedlander, A. L.↗
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Satellite encounter opportunities of the Grand Tour missions
Multiple outer planets flyby opportunities during 1976-1980 Grand Tour missions launch period, presenting computer generated specific encounter dates and flyby distances
Penzo, P. A.↗
On obtaining lunar mission launch opportunities
A general procedure for predicting launch opportunities for the RAE-B lunar orbiter mission is presented. It is shown that knowledge of the earth-moon distance and lunar phase and declination are sufficient to determine launch periods consistent with present mission constraints and to approximately predict launch, transfer, and arrival parameters such as park orbit coast time, the possiblity of shadows in all phases of the mission, arrival energy, and the amount of sunlit orbit time in the lunar orbit. Constraints on RAE-B include bounds on the spin axis-sun angle in the translunar trajectory, an upper limit on the arrival energy, and a minimum time for sunlight duration in lunar orbits are being considered for the mission. Comparisons are made of relevant parameters for the two cases. The general features of launch, transfer, and arrival parameters are discussed and are shown to be a function of lunar declination, flight time, and launch azimuth.
Swartwood, H., Jr.↗
Satellites for U.S. education - Needs, opportunities and systems.
This paper presents results of a continuing interdisciplinary study of the potential applications of Fixed- and Broadcast-Satellites for educational information transfer in the United States for the period 1975-1985. The status of U.S. education is examined and needs, trends and issues are discussed. The existing educational telecommunications infrastructure is examined and opportunities for satellite services are defined. Potential uses include networking of educational institutions and service centers for delivery of public and instructional television, computer-aided instruction, computing and information resources to regions and groups not now adequately served. Systems alternatives and some of the organizational and economic issues inherent in the deployment of an educational satellite system are discussed.-
Morgan, R. P.↗
Ballistic mode Mercury orbiter mission opportunity handbook
Significant payloads in Mercury orbit can be achieved through use of high-thrust, chemical propulsion systems on ballistic trajectories. Interplanetary trajectory characteristics are presented, for Venus swingbys to Mercury, were multiple revolutions about the sun are allowed on each leg to provide low energy mission in 1977, 1980, 1985 and 1988. Guidance and navigation results are shown for each opportunity. Additionally, the use of midcourse maneuvers and multiple Venus swingbys are explored as means of further reducing the energy requirements.
Hollenbeck, G. R.↗
Ballistic mode Mercury orbiter mission opportunity handbook extension
Interplanetary trajectory characteristics are presented, for Venus swingbys to Mercury, where multiple revolutions about the Sun are permitted. Additional consideration is given to the use of multiple Venus swingbys and/or to midcourse, near perilhelion, propulsive maneuvers to improve the performance of the mission as measured in terms of payload in Mercury orbit. Missions in 1980, 1983, 1985 and 1988 were analyzed with navigation results also developed. An exploratory investigation established the availability of low energy mission opportunities in 1991, 1994, 1996 and 1999.
Hollenbeck, G. R.↗
Opportunities for space surveys of moisture anomalies
Review of a combination of infrared scanning, unsupervised spectroscopic classification, change detection, and perturbation spectroscopy for monitoring anomalous moisture exchange from space. Infrared sensors have been developed which can monitor the solar reflectance from droplet distributions in vegetation and clouds, the absorption of thermal radiation by water vapor, and the microwave attenuation by atmospheric water. Unsupervised spectroscopic classification techniques are emerging which have the potential to subdivide strip maps from infrared scanners into different moisture targets. Intersecting and parallel spacecraft orbits provide opportunities to study the change of recognized targets between two scans and to recognize anomalous moisture exchange from those changes which significantly exceed the statistical uncertainty of the spectroscopic target signature. The new concept of perturbation spectroscopy shows a potential to quantitatively determine the change of integrated water vapor pressure with a minimum of 'atmospheric truth' and with low spectroscopic resolution that is typical of simple interference filters.
Krause, F. R.↗
A study of unmanned mission opportunities to comets and asteroids
Several unmanned multiple-target mission opportunities to comets and asteroids were studied. The targets investigated include Grigg-Skjellerup, Giacobini-Zinner, Tuttle-Giacobini-Kresak, Borrelly, Halley, Schaumasse, Geographos, Eros, Icarus, and Toro, and the trajectories consist of purely ballistic flight, except that powered swingbys and deep space burns are employed when necessary. Optimum solar electric rendezvous trajectories to the comets Giacobini-Zinner/85, Borrelly/87, and Temple (2)/83 and /88 employing the 8.67 kw Sert III spacecraft modified for interplanetary flight were also investigated. The problem of optimizing electric propulsion heliocentric trajectories, including the effects of geocentric launch asymptote declination on launch vehicle performance capability, was formulated, and a solution developed using variational calculus techniques. Improvements were made to the HILTOP trajectory optimization computer program. An error analysis of high-thrust maneuvers involving spin-stabilized spacecraft was developed and applied to a synchronous meteorological satellite mission.
Mann, F. I.↗
Science planning and mission strategy for the 1979 Jupiter/Uranus opportunity
An intensive science and mission planning effort has been underway for several years to develop the next logical candidate mission to the outer planets following the Mariner Jupiter/Saturn 1977 Mission. The highest priority candidate that emerges from this effort is the launch of a MJS-derived Mariner spacecraft to Uranus during the 1979 Jupiter/Uranus opportunity. Since 1972 when the Outer Planets Science Advisory Group recommended MJU79 to follow MJS77, four other science groups have addressed this issue and arrived at the same recommendation. Currently, the planning effort is most intensive and the paper will report the past and present determinations of the various science and mission planning activities, emphasizing science value, technical factors and fiscal constraints.
Moore, J. W.↗
Launch opportunity classification of VEGA and delta V-EGA trajectories to the outer planets
Two concepts in spacecraft trajectory design which have been proposed by Hollenbeck (1975) and Bender and Friedlander (1975) are considered. Both concepts are intended for planetary missions and require an earth reencounter created by either a Venus gravity assist (VEGA) or a large midcourse impulse (delta V-EGA). In the case of outer planet missions, the new concepts offer significantly lower launch energy requirements than the direct ballistic flight mode. However, at least an additional two years flight time is needed for geometry phasing to set up the earth reencounter. A description is given of the trajectory characteristics for the two concepts. Attention is also given to the method of analysis used for the studies, aspects of trajectory generation, payload calculations, and target opportunity data.
Stancati, M. L.↗
The Pioneer 11 1976 solar conjunction: A unique opportunity to explore the heliographic latitudinal variations of the solar corona
The 1976 Pioneer II Solar Conjunction provided the opportunity to accumulate a substantial quantity of doppler noise data over a dynamic range of signal closest approach point heliographic latitudes. The observed doppler noise data were fit to the doppler noise model ISED, and the deviations of the observed doppler noise data from the model were used to construct a (multiplicative) function to describe the effect of heliographic latitude. This expression was then incorporated into the ISED model to produce a new doppler noise model-ISEDB.
Berman, A. L.↗
Space Industrialization. Volume 2: Opportunities, Markets and Programs
The nature of space industrialization and the reasons for its promotion are examined. Increases in space industry activities to be anticipated from 1980 to 2010 are assessed. A variety of future scenarios against which space industrialization could evolve were developed and the various industrial opportunities that might constitute that evolution were defined. The needs and markets of industry activities were quantitatively and qualitatively assessed and messed. The various hardware requirements vs. time (space industry programs) as space industrialization evolves are derived and analyzed.
Source record↗
Future opportunities in digital avionics - NASA's role
The current avionics program of NASA is briefly reviewed with attention given to digital operations (navigation, communication and guidance), integrated controls (dealing with aircraft stability, handling qualities, load alleviation, and propulsion) and cockpit avionics. NASA's role is discussed in terms of the present avionics program and the future opportunities that are addressed in long-range plans.
Taylor, L. W., Jr.↗
1983 and 1985 multi-revolution opportunities to Mars
The use of Earth-Mars trajectories requiring more than one revolution about the Sun is discussed. Such trajectories appear to merit consideration in the next mission to Mars. Some unfamiliar mechanics of these orbits are explained and a nomenclature developed for them. Two candidate multi-revolution opportunities are discussed in some detail and compared to ordinary trajectories. It is shown that such trajectories can yield significantly better payloads in the mid-1980s than ordinary trajectories.
Roberts, P. H., Jr.↗
A Mars orbiter/rover/penetrator mission for the 1984 opportunity
A point design mission is described that utilizes the 1984 opportunity to extend the exploration of Mars after the successful Viking operations and provide the additional scientific information needed before conducting a sample return mission. Two identical multi-element spacecraft are employed, each consisting of (1) an orbiter, (2) a Viking-derived landing system that delivers a heavily instrumented, semi-autonomous rover, and (3) three penetrators deployed from the approach trajectory. Selection of the orbit profiles requires consideration of several important factors in order to satisfy all of the mission goals.
Hastrup, R.↗
Technology needs and opportunities for future NASA missions
The process of forecasting NASA's future needs and missions as well as the technologies relevant to the projected requirements is examined with emphasis on large space system technology. A technology model (set of generic systems) is presented to assist in the development of technology program options, to identify major technology areas requiring concentrated effort, and to serve as an evaluation criteria for current technology programs. The model is applied to considerations of near and far term opportunities for exploration of the universe, global services, utilization of the space environment, and the space transportation system.
Sadin, S. R.↗
Opportunities for space exploitation to year 2000 - A challenge for advanced technology
Application of satellite remote sensing to wide range of areas requires the development or improvement of specialized spaceborne and ground-based equipment and systems. This paper describes some of the important areas for remote sensing and the opportunities that must be met in order to advance technology and capabilities for the exploitation of space to the year 2000.
Calio, A. J.↗
New opportunities for future small civil turbine engines - Overviewing the GATE studies
This paper presents an overview of four independent studies that explore the opportunities for future General Aviation Turbine Engines (GATE) in the 150-1000 SHP class. Detroit Diesel Allison, Garrett/AiResearch, Teledyne CAE, and Williams Research participated along with several airframers. These studies forecasted the potential impact of advanced technology turbine engines in the post-1988 market, identified important aircraft and missions, desirable engine sizes, engine performance and cost goals. Parametric evaluations of various engine cycles, configurations, design features, and advanced technology elements defined baseline conceptual engines for each of the important missions identified by the market analysis. Both fixed-wing and helicopter aircraft, and turboshaft, turboprop, and turbofan engines were considered. All four companies predicted sizable performance gains (e.g., 20% SFC decrease), and three predicted large engine cost reductions of sufficient magnitude to challenge the reciprocating engine in the 300-500 SHP class. Key technology areas were recommended for NASA support in order to realize these improvements.
Strack, W. C.↗