Outer Solar System A Program for Exploration, Report of a Study (1969) / Chapter Skim
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PLUTO, SATELLITES, ASTEROIDS, AND COMETS
PLUTO, SATELLITES, ASTEROIDS, AND COMETS
Pages 80-89
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From page 80... ...
The first basic parameter deducible from an imaging experiment is the diameter, and knowledge of the diameter could settle whether some or all of the satellites are essentially composed of rock or of ice. Even without being directed toward a specific satellite flyby, an imaging system directed toward exploring a major planet, and of appropriate resolution and format for that planet, would, for instance, if directed toward Jupiter, automatically come close enough to a satellite to resolve basic geologic structures such as impact craters, possibly volcanic structures, mountain chains (which would be interesting indeed if found -- unless estimates of satellite size and mass are grossly in error)
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From page 81... ...
Probably the most significant contribution to satellite research in the near future will come when ground-based and spacecraft radar capabilities are advanced to the point where surface reflectivities, roughness, and dielectric constant are measurable for the larger satellites of Jupiter and Saturn. Data from ground-based and spacecraft radar can also greatly contribute to our knowledge of satellite rotation rates and axis orientations, their sizes, densities, and orbits, and the gravity fields of Jupiter and Saturn.
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From page 82... ...
The geometrical parameters of the rings need determination because the most recent and presumably most accurate values imply that theCassini division is not in resonance with Mimas perturbations. This is not so surprising, perhaps, when one realizes that the rings show no evidence of a gap at the corresponding Janus resonance which one might expect to be even more potent as a gap ejector on the venerable simple picture hitherto invoked for the Cassini division.
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From page 83... ...
Depending on one's point of interest in this interval, all the discussion above concerning satellites and Saturn's rings applies, except, perhaps, atmospheric considerations. Since the gravitational attraction of these bodies is such that a soft landing is little more than a docking maneuver, the feasibility of surface probe missions and sample return should be given further study.
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From page 84... ...
Pluto's spectral energy distribution shows no ultraviolet brightening characteristic of a Rayleigh scattering atmosphere; however, its rotational light curve suggests brightening at the morning terminator as though an atmospheric component had formed frost during the night. The possibility of observing He, A, and Ne cannot now be ruled out on theoretical grounds.
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From page 85... ...
In addition, the feasibility of a sufficiently precise rendezvous maneuver that the spacecraft would slowly fall into the comet nucleus after burn-out should be considered, in which case more sophisticated probe-type instruments for chemical analysis and isotopic ratio determination would be strongly urged.
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