Tethers and asteroids for artificial gravity assist in the solar system
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Penzo, P. A.↗
Engineering topics
Mayer, H. L.
Publications and source records attributed to Mayer, H. L..
Report of the Constellations Panel
The purpose of a constellation is to provide a mode of distributing space systems in a method that could be advantageous and not eliminating the consolidation/aggregation advantages. The applicability of stabilization concepts to various orbital conditions was defined.
Bents, D. J.↗
Tethers and asteroids for artificial gravity assist in the solar system
Analytical models are defined for gravity-assist trajectory changes for spacecraft passing massive compact bodies. The models are applied in an examination of the benefits of lowering a tether to an asteroid during a flyby in order to gain a trajectory change equivalent to that from a massive body (planet). Direct flybys yield velocity gains while retrograde flybys shed velocity. The magnitude of the effects are a function of the proximity to the body during flyby. This inherently limits the gravity assist technique used around planets, which usually have atmospheres and can have intense radiation fields. If a spacecraft could extend a tether (such as to be tested on the Orbiter) to snag on an asteroid surface, the potential trajectory/velocity change of the spacecraft would be limited mainly by the tether strength. The encounter physics are treated as a soft collision. Possible applications of the asteroid tether technique are outer planet, Mars and main belt asteroid exploration missions.
Penzo, P. A.↗
Swarms: Optimum aggregations of spacecraft
Swarms are aggregations of spacecraft or elements of a space system which are cooperative in function, but physically isolated or only loosely connected. For some missions the swarm configuration may be optimum compared to a group of completely independent spacecraft or a complex rigidly integrated spacecraft or space platform. General features of swarms are induced by considering an ensemble of 26 swarms, examples ranging from Earth centered swarms for commercial application to swarms for exploring minor planets. A concept for a low altitude swarm as a substitute for a space platform is proposed and a preliminary design studied. The salient design feature is the web of tethers holding the 30 km swarm in a rigid two dimensional array in the orbital plane. A mathematical discussion and tutorial in tether technology and in some aspects of the distribution of services (mass, energy, and information to swarm elements) are included.
Mayer, H. L.↗
Advanced space system concepts and their orbital support needs (1980 - 2000). Volume 1: Executive summary
The likely system concepts which might be representative of NASA and DoD space programs in the 1980-2000 time period were studied along with the programs' likely needs for major space transportation vehicles, orbital support vehicles, and technology developments which could be shared by the military and civilian space establishments in that time period. Such needs could then be used by NASA as an input in determining the nature of its long-range development plan. The approach used was to develop a list of possible space system concepts (initiatives) in parallel with a list of needs based on consideration of the likely environments and goals of the future. The two lists thus obtained represented what could be done, regardless of need; and what should be done, regardless of capability, respectively. A set of development program plans for space application concepts was then assembled, matching needs against capabilities, and the requirements of the space concepts for support vehicles, transportation, and technology were extracted. The process was pursued in parallel for likely military and civilian programs, and the common support needs thus identified.
Bekey, I.↗
Advanced space system concepts and their orbital support needs (1980 - 2000). Volume 2: Final report
The results are presented of a study which identifies over 100 new and highly capable space systems for the 1980-2000 time period: civilian systems which could bring benefits to large numbers of average citizens in everyday life, much enhance the kinds and levels of public services, increase the economic motivation for industrial investment in space, expand scientific horizons; and, in the military area, systems which could materially alter current concepts of tactical and strategic engagements. The requirements for space transportation, orbital support, and technology for these systems are derived, and those requirements likely to be shared between NASA and the DoD in the time period identified. The high leverage technologies for the time period are identified as very large microwave antennas and optics, high energy power subsystems, high precision and high power lasers, microelectronic circuit complexes and data processors, mosaic solid state sensing devices, and long-life cryogenic refrigerators.
Bekey, I.↗
Advanced space system concepts and their orbital support needs (1980 - 2000). Volume 3: Detailed data. Part 1: Catalog of initiatives, functional options, and future environments and goals
The following areas were discussed in relation to a study of the commonality of space vehicle applications to future national needs: (1) index of initiatives (civilian observation, communication, support), brief illustrated description of each initiative, time periods (from 1980 to 2000+) for implementation of these initiatives; (2) data bank of functional system options, presented in the form of data sheets, one for each of the major functions, with the system option for near-term, midterm, and far-term space projects applicable to each subcategory of functions to be fulfilled; (3) table relating initiatives and desired goals (public service and humanistic, materialistic, scientific and intellectual); and (4) data on size, weight and cost estimations.
Bekey, I.↗
Advanced space system concepts and their orbital support needs (1980 - 2000). Volume 4: Detailed data. Part 2: Program plans and common support needs (a study of the commonality of space vehicle applications to future national needs
The methodology of alternate world future scenarios is utilized for selecting a plausible, though not advocated, set of future scenarios each of which results in a program plan appropriate for the respective environment. Each such program plan gives rise to different building block and technology requirements, which are analyzed for common need between the NASA and the DoD for each of the alternate world scenarios. An essentially invariant set of system, building block, and technology development plans is presented at the conclusion, intended to allow protection of most of the options for system concepts regardless of what the actual future world environment turns out to be. Thus, building block and technology needs are derived which support: (1) each specific world scenario; (2) all the world scenarios identified in this study; or (3) generalized scenarios applicable to almost any future environment. The output included in this volume consists of the building blocks, i.e.: transportation vehicles, orbital support vehicles, and orbital support facilities; the technology required to support the program plans; identification of their features which could support the DoD and NASA in common; and a complete discussion of the planning methodology.
Bekey, I.↗