Outer Solar System A Program for Exploration, Report of a Study (1969) / Chapter Skim
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MAJOR RECOMMENDATIONS
MAJOR RECOMMENDATIONS
Pages 7-24
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From page 7... ...
The rare opportunities for planetary voyages, the length of these voyages, their cost, and the long times required for preparing spacecraft and experiments all imply that planning for exploration of the outer solar system must take place years in advance of the actual missions. It is imperative that a decision be arrived at determining the character and scope of the program for the exploration of the solar system.
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From page 8... ...
In presenting the scientific objectives we recognize that missions to the outer planets provide major values other than scientific. The requirements of the missions on technology will undoubtedly stimulate advances with farreaching consequences.
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From page 9... ...
to describe the motions of the atmospheres of the major planets and to characterize their temperature-densitycomposition structure; 5. to make a detailed study for each of the outer planets of the external magnetic field and respective particle population, associated radio emissions, and magnetospheric particle-wave interactions; 6.
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From page 10... ...
The carbon-l2 to carbon-l3 ratio is one of great interest; but other isotopic ratios less subject to change by neutron capture would be even more revealing in view of the probability that solar surface electromagnetic effects may have modified materials exterior to the sun during the early stages of solar system development. In view of these considerations, we identify as a prime objective for missions to the outer planets the determination of the relative abundance and isotopic ratios of hydrogen, helium, carbon, and heavy elements up to mass 40 in the atmospheres of all the outer planets.
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From page 11... ...
A prime objective of outer planetary exploration is, therefore, the characterization of lower atmospheric environments in terms of biologically significant parameters and a search for and an identification of organic substances of importance to life. Atmospheric Circulation We would like to understand the terrestrial atmosphere much better than we do.
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From page 12... ...
An objective of the exploration program should be the study of the dynamics of the atmospheres of the major planets. Magnetic Fields and the Radiation Belts of the Giant Planets The earth's magnetic field is due to motions in an electrically conducting core.
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From page 13... ...
Because of this, a prime objective of the exploration of the outer solar system should be a detailed study of the external magnetic field and charged-particle populations in the vicinity of the major planets. This information will be most valuable if concomitant observations of the nonthermal radio emissions originating through cooperative phenomena are made in situ.
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From page 14... ...
The understanding of galactic cosmic rays will be very much enhanced by observation in a location unaffected by the solar magnetic fields and free of energetic solar particles that are so abundant at l AU in the plane of the ecliptic. These kinds of observations are needed if we are to untangle the effects of local magnetic fields on the properties of the cosmic rays.
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From page 15... ...
The entry probe would carry a mass spectrometer to sample the composition of the atmosphere as well as instruments to determine temperature, density, pressure, and physical and chemical properties of the clouds. The instrumentation remaining on the spacecraft would be designed to measure fields and particles over a wide energy range and to detect decametric radio emissions.
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From page 16... ...
Missions Requiring Further Study The smaller bodies of the outer solar system may contain information vital to the understanding of the history and origin of the solar system. In particular, detailed in situ observations of the asteroids may be valuable in tying together the vast array of information that has been secured by observations on meteorites.
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From page 17... ...
It is recognized that there are advantages to either system both scientifically and technically. In order to conduct studies of energetic particles, plasmas, magnetic fields, and radio emissions in the interplanetary medium, planetary magnetosphere, and radiation belts, it is essential that the detector systems scan directionally.
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From page 18... ...
We recommend that NASA develop a hybrid spinning spacecraft, a portion of which could be despun; the total spacecraft would act as an optimum laboratory bench for the broad classes of experiments contemplated in the exploration of the outer solar system. Telemetry Data Coverage An important requirement of the scientific studies to be conducted during interplanetary cruise is effectively continuous data coverage.
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From page 19... ...
We recommend that special attention be devoted to the design of an over-all system that can survive the Jovian environment. INSTRUMENTATION The instrumentation for determination of the particles and fields in interplanetary space and near the major planets is well in hand except for the over-all design considerations noted above.
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From page 20... ...
We recommend that NASA initiate design studies for suitable mass spectrometers. Visual Imaging The study of cloud motions which in turn will lead to critical information regarding the dynamics of the atmospheres of the major planets requires visual imaging over a broad range of horizontal scales.
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From page 21... ...
for experiments that are independent of any spacecraft. In various sections of this report, the scientific possibilities are outlined in terms of studies of: planetary and satellite atmospheres; solar, interplanetary, and planetary plasmas and magnetic fields; planetary radii, masses, and detailed gravity fields; spin rates, radii, and masses of the larger satellites and Pluto; surfaces and topography of the satellites and Pluto; deep atmospheres and possible surfaces of the Jovian planets; satellite and planetary orbits; ring thickness and sizes, reflectivity, velocity distribution, and number density of the particles in the rings of Saturn; the mass of the asteroid belt and possibly the mass, rotations, and reflectivity of a few large asteroids; and several fundamental relativistic effects.
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From page 22... ...
and maximum scientific purposes. To this end, we recommend that for the missions to the outer planets, a Radio Science and Celestial Mechanics Scientific Team be selected at an early enough date to be able to affect the design of the spacecraft radio systems and the operational capabilities of the ground-based terminals of the Deep Space Net.
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From page 23... ...
We, therefore, recommend that NASA support theoretical and experimental studies of the equations of state of hydrogen and of the hydrogen-helium system. Use of a Large Radio Antenna Array Apparently the only ground-based possibility for directly studying the deep atmosphere of the major planets is by means of radio and radar observations at wavelengths between l0 and l00 cm.
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From page 24... ...
Although designed primarily for galactic and extragalactic observations, several large antenna arrays now being planned will be capable of making valuable planetary measurements. We recommend that the designs of large radio antenna arrays include provisions for realtime pencil-beam observations of the planets and that NASA support planetary programs that make use of such arrays.
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