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Dolginov SS, Yeroshenko YG, Zhuzgov LN. Magnetic field in the very close neighborhood of Mars according to data from the Mars 2 and Mars 3 spacecraft. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja078i022p04779] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bogdanov AV, Vaisberg OL. Structure and variations of solar wind-Mars interaction region. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja080i004p00487] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Dolginov SHSH, Yeroshenko YEG, Zhuzgov LN. The magnetic field of mars according to the data from the Mars 3 and Mars 5. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja081i019p03353] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Coleman PJ, Smith EJ, Davis L, Jones DE. The radial dependence of the interplanetary magnetic field: 1.0-1.5 AU. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja074i011p02826] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Duru F, Gurnett DA, Frahm RA, Winningham JD, Morgan DD, Howes GG. Steep, transient density gradients in the Martian ionosphere similar to the ionopause at Venus. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009ja014711] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- F. Duru
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - D. A. Gurnett
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - R. A. Frahm
- Southwest Research Institute; San Antonio Texas USA
| | | | - D. D. Morgan
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
| | - G. G. Howes
- Department of Physics and Astronomy; University of Iowa; Iowa City Iowa USA
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Affiliation(s)
- P H Abelson
- GEOPHYSICAL LABORATORY, CARNEGIE INSTITUTION OF WASHINGTON, WASHINGTON, D. C
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Cain JC, Beaumont P, Holter W, Wang Z, Nevanlinna H. The magnetic bode fallacy. ACTA ACUST UNITED AC 1995. [DOI: 10.1029/95je00504] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Vaisberg OL, Luhmann JG, Russell CT. Plasma observations of the solar wind interaction with Mars. ACTA ACUST UNITED AC 1990. [DOI: 10.1029/jb095ib09p14841] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bogdanov AV. Mars satellite Deimos interaction with the solar wind and its influrence on flow around Mars. ACTA ACUST UNITED AC 1981. [DOI: 10.1029/ja086ia08p06926] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Smith E, Sonett C. Extraterrestrial Magnetic Fields: Achievements and Opportunities. ACTA ACUST UNITED AC 1976. [DOI: 10.1109/tge.1976.294447] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Simpson JA, Eraker JH, Lamport JE, Walpole PH. Search by Mariner 10 for Electrons and Protons Accelerated in Association with Venus. Science 1974; 183:1318-21. [PMID: 17791375 DOI: 10.1126/science.183.4131.1318] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The University of Chicago instrumnents on board the Mariner 10 spacecraft bound for Mercury have measured energy spectra and fluxes of electrons from 0.18 to 30 million electron volts and protons from 0.5 to 68 million electron volts along the plasma wake and in the bow shock regions associated with Venus. Unusually quiet solar conditions and improved instrumentation made it possible to search for much lower fluxes of protons and electrons in similar energy regions as compared to earlier Mariner missions to Venus-that is, lower by a factor of 10(2) for protons and 10(3) for electrons. We found no evidence for electrons or protons either in the form of increases of intensity or energy spectral changes in the vicinity of the planet, nor any evidence of bursts of radiation in or near the observed bow shock where bursts of electrons might have been expected in analogy with the bow shock at the earth. The importance of these null results for determining the necessary and sufficient conditions for particle acceleration is discussed with respect to magnetometer evidence that Venus does not have a magnetosphere.
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Metzger AE, Arnold JR. Gamma ray spectroscopic measurements of Mars. APPLIED OPTICS 1970; 9:1289-1303. [PMID: 20076376 DOI: 10.1364/ao.9.001289] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A gamma ray spectrometer placed in orbit around Mars is expected to yield significant compositional data which can be related to the evolution of that planet. Components of the observable gamma ray flux come from the Martian surface, galactic and intergalactic space, and the spacecraft itself. The flux can be detected by a scintillation crystal or solid state detector, either of which combines efficiency of detection with energy resolution, and returns information to the earth as a pulse height distribution in order to detect characteristic energy line structure. The data will be evaluated for evidence of elemental differentiation with reference to terrestrial, meteoritic, solar, and lunar abundances. A lengthy mission will allow the surface of Mars to be mapped in a search for possible correlations between composition and topography or albedo.
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Abstract
Venus has daytime and nighttime ionospheres at the positions probed by radio occulation. The main layers are thin by terrestrial standards, with the nighttime peak concentration of electrons being about two orders of magnitude below that of the daytime peak. Above the nighttime peak were several scale-height regimes extending to a radius of at least 7500, and probably to 9700, kilometers from the center of Venus. Helium and hydrogen at plasma temperatures of 600 degrees to 1100 degrees K seem indicated in the regimes from 6300 to 7500 kilometers, with cooler molecular ions in lower regions. Above the daytime peak a sharp plasmapause was discovered, marking a sudden transition from appreciable ionization concentrations near Venus to the tenuous conditions of the solar wind. This may be indicative of a kind of interaction of the magnetized solar wind with a planetary body that differs from the two different kinds of interaction characterized by Earth and by Moon. For Venus and probably for Mars, the magnetic field of the solar wind may pile up in front of the conducting ionosphere, form an induced magnetosphere that ends at the plasmapause, above which any ionosphere that tends to form is swept away by the shocked solar wind that flows between the stand-off bow-shock and the magnetopause. The neutral atmosphere was also probed and a surface reflection may have been detected, but the data have not yet been studied in detail. Results are consistent with a super-refractive atmosphere, as expected from Soviet measurements near the surface. Thus, two unusual features of Venus can be described in terms of a light trap in the lower atmosphere, and a magnetic trap in the conducting ionosphere.
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Brown RT. Planetary Magnetic Fields and Rotation. Science 1967. [DOI: 10.1126/science.158.3801.674.a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Robert T. Brown
- Department of Space Science, Rice University, Houston, Texas
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Brown RT. Planetary Magnetic Fields and Rotation. Science 1967. [DOI: 10.1126/science.158.3801.674-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Robert T. Brown
- Department of Space Science, Rice University, Houston, Texas
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Abstract
The small magnetic field strength observed near Mars by Mariner IV suggests that protons from the solar wind may enter the Martian atmosphere and produce ionization in addition to that produced by ultraviolet light and x-rays. It is found that solar protons produce a thin ionized layer at a rate of the order of 3 x 10(3) per cubic centimeter per second at a depth corresponding to the F(1) region in the terrestrial atmosphere. Unless the effective recombinative coefficient is very large (greater than 10(-5) centimeter cubed per second) or unless unusual diffusion effects are present, this layer should have been detected by Mariner IV, and therefore must be present in one of the observed ionized regions. Because of its very compact shape, the subsidiary maximum near 95 kilometers discovered in the Mariner-IV occultation experiment may be the proton ionization peak. If so, the major 120-kilometer maximum is an F(2) layer. Distinction between photon and proton ionization regions can be made by microwave occultation experiments aboard planetary orbiters.
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Abstract
The sterility requirements for landed spacecraft tentatively adopted in the COSPAR resolution of 1964 are so severe as to pose a major obstacle to planetary exploration. This by itself would not justify modification of the re quirements, since preservation of the biological integrity of Mars is essential for proper exploration of the planet. However, when the physical and biological assumptions underlying the COSPAR recommendations are com pared with actual conditions on Mars, as established by recent observations, it becomes apparent that the COSPAR as sumptions are unrealistic in important respects. Specifically, the belief that eolian erosion on Mars can effect the release of spores trapped in the interior of solids in periods of time that are short compared with the time scale of the unmanned space program is unsup ported by either observation or theory. On the contrary, the analysis suggests that rates of eolian erosion on Mars are very low. Similarly, present knowledge of the Martian environment opposes the view that terrestrial microorganisms would readily contaminate the planet. The combination of dryness, lack of oxygen, and high ultraviolet flux makes the surface of Mars peculiarly unsuit able for the multiplication of terrestrial organisms. Recent studies give little sup port to the proposal that significant areas of geothermal activity exist on Mars. These various findings suggest that the COSPAR-recommended constraints could be substantially relaxed without compromising to any significant degree the biological condition of Mars. In particular, a distinction needs to be made between microorganisms trapped in solids and those on exposed sur faces of landed spacecraft. Surface sterility is an unconditional require ment, in the sense that it is imposed by considerations unrelated to the nature of the Martian environment. Sterilization of the interior of solids to the extreme level recommended by COSPAR, however, is based on the as sumption that entrapped organisms con stitute a substantial hazard to the ecology of Mars. This assumption now seems unjustified, and the need for a high degree of interior sterility is doubt ful. Current spacecraft-sterilization pol icies should be revised accordingly.
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Reiff GA. Mariner IV: Developing the Scientific Experiment. Science 1966; 151:413-7. [PMID: 17798511 DOI: 10.1126/science.151.3709.413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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O'gallagher JJ, Simpson JA. Search for Trapped Electrons and a Magnetic Moment at Mars by Mariner IV. Science 1965; 149:1233-9. [PMID: 17747452 DOI: 10.1126/science.149.3689.1233] [Citation(s) in RCA: 44] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Mariner IV spacecraft on 14-15 July 1965 passed within 9850 kilometers of Mars, carrying a solid-state charged-particle telescope which could detect electrons greater than 40 kiloelectron volts and protons greater than 1 million electron volts. The trajectory could have passed through a bow shock, a transition region, and a magnetospheric boundary where particles could be stably trapped for a wide range of Martian magnetic moments. No evidence of charged-particle radiation was found in any of these regions. In view of these results, an upper limit is established for the Martian magnetic moment provided it is assumed that the same physical processes leading to acceleration and trapping of electrons in Earth's magnetic field would be found in a Martian magnetic field. On this basis, the upper limit for the Martian magnetic moment is 0.1 percent that of Earth for a wide range of postulated orientations with respect to the rotational axis of Mars. The implications of these results for the physical and biological environment of Mars are briefly discussed.
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