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271.
S.A. Haider Jayesh P. Pabari J. Masoom Siddhi Y. Shah 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2019,63(7):2260-2266
We have solved the Maxwellian equations of electromagnetic waves which oscillate within the cavity formed in the lower ionosphere of Mars between 0 and 70?km. The electrical conductivity and Schumann Resonance (SR) frequencies are calculated in the lower ionosphere of Mars, in the presence of a major dust storm that occurred in Martian Year (MY) 25 at low latitude region (25°–35°S). It is found that the atmospheric conductivity reduced by one to two orders of magnitude in the presence of a dust storm. It represents a small dust layer at about 25–30?km altitudes where lightning can occur. We also found that the SR frequencies peak at?~18?km with values 19.9, 34.5 and 48.8?Hz for the modes l?=?1, 2 and 3, respectively, in the non-homogeneous medium. Our results indicate that practical or measurable values of SR are dependent on the altitudes. 相似文献
272.
A.P. Kireev A.M. Krymskii 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
The pattern of the magnetic field/plasma convection can be, to some extent, recovered from the magnetic field measurements by employing either theoretical or numerical models. We use the MAG/ER day-time measurements of the magnetic field at the altitudes from 90 to 180 km during the elliptical orbits of MGS. Analysis of the altitude variation of the characteristics of the large-scale magnetic fields, which were measured some distance away from strong crustal magnetic anomalies, is summarized. The low density of the Martian atmosphere together with the crustal magnetization result in critical differences in plasma convection which are followed by remarkable differences of the magnetic field features within the ionosphere of Venus and Mars (even in its northern hemisphere where the crustal magnetization is, on the average, low) and distribution of currents. 相似文献
273.
A. S. Wong S. K. Atreya V. Formisano Th. Encrenaz N. I. Ignatiev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2004,33(12):2236-2239
Considering the possibility of outgassing from some localized sources on Mars, we have developed a one-dimensional photochemical model that includes methane (CH4), sulfur dioxide (SO2) and hydrogen sulfide (H2S). Halogens were considered but were found to have no significant impact on the martian atmospheric chemistry. We find that the introduction of methane into the martian atmosphere results in the formation of mainly formaldehyde (CH2O), methyl alcohol (CH3OH) and ethane (C2H6), whereas the introduction of the sulfur species produces mainly sulfur monoxide (SO) and sulfuric acid (H2SO4). Depending upon the flux of the outgassed molecules from possible hot spots, some of these species and the resulting new molecules may be detectable locally, either by remote sensing (e.g., with the Planetary Fourier Spectrometer on Mars Express) or in situ measurements. 相似文献
274.
M. Ya. Marov V. S. Avduevsky E. L. Akim T. M. Eneev R. S. Kremnev S. D. Kulikov K. M. Pichkhadze G. A. Popov G. N. Rogovsky 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2004,33(12):2276-2280
As an important milestone in the exploration of Mars and small bodies, a new generation space vehicle “Phobos-Grunt” is planned to be launched by the Russian Aviation and Space Agency. The project is optimized around a Phobos sample return mission and follow up missions targeted to study some main asteroid belt bodies, NEOs and short period comets. The principal constraint is use of the “Soyuz-Fregat” rather than the “Proton” launcher to accomplish these challenging goals. The vehicle design incorporates innovative SEP technology involving electrojet engines that allowed us to increase significantly the mission's energetic capabilities, as well as highly autonomous on-board systems. Basic criteria underlining the “Phobos-Grunt” mission scenario, scientific objectives and rationale including Mars observations during the vehicle's insertion into Mars orbit and Phobos approach maneuvers, are discussed and an opportunity for international cooperation is suggested. 相似文献
275.
276.
277.
Lauren E. Fletcher Julio E. Valdivia-Silva Saul Perez-Montaño Renee M. Condori-Apaza Catharine A. Conley Christopher P. McKay 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
The objective of this work was to investigate the variability of surface organic carbon within the hyper-arid Yungay region of the Atacama Desert. The fraction of Labile Organic Carbon (LOC) in these samples varied from 2 to 73 μg per gram of soil with a bi-modal distribution with average content of 17 ± 9 μg LOC and 69 ± 3 μg LOC for “low” and “high” samples, respectively. Interestingly, there was no relation between organic levels and geomorphologic shapes. While organics are deposited and distributed in these soils via eolic processes, it is suggested that fog is the dynamic mechanism that is responsible for the variability and peaks in organic carbon throughout the area, where a “high” LOC content sample could be indicative of a biological process. It was determined that there was no significant difference between topological feature or geographical position within the hyper-arid samples and LOC. This very curious result has implications for the investigation of run-off gullies on the planet Mars as our work suggests a need for careful consideration of the expectation of increases in concentrations of organic materials associated with following aqueous altered topology. 相似文献
278.
Yuichiro Ezoe Kumi Ishikawa Takaya Ohashi Noriko Y. Yamasaki Kazuhisa Mitsuda Ryuichi Fujimoto Yoshizumi Miyoshi Naoki Terada Yasunobu Uchiyama Yoshifumi Futaana 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Recent results of solar system planets observed with the Japanese X-ray astronomy satellite Suzaku are reviewed. Thanks to the low instrumental background and good energy resolution, X-ray CCDs onboard Suzaku are one of the best probes to study diffuse X-ray emission. An overview of the Suzaku data of Jupiter and Earth is presented, along with preliminary results of Mars. Firstly, diffuse hard X-ray emission is discovered in 1–5 keV at Jovian radiation belts. Its spectrum is represented by a power-law continuum with a photon index of ∼1.4. This emission could originate from inverse-Compton scattering of solar photons by tens MeV electrons. Secondly, variable diffuse soft X-rays are serendipitously found during observations in the directions of the north ecliptic pole and galactic ridge. Good time correlations with the solar wind and emission lines found in the X-ray spectra are firm evidences of a solar wind charge exchange emission with Earth’s exosphere. Thirdly, diffuse X-ray emission from Martian exosphere via the solar wind charge exchange is investigated for the first time at solar minimum. A stringent upper limit on the density of the Martian exosphere is placed from the Suzaku data. 相似文献
279.
Euan Nisbet Kevin Zahnle M. V. Gerasimov Jörn Helbert Ralf Jaumann Beda A. Hofmann Karim Benzerara Frances Westall 《Space Science Reviews》2007,129(1-3):79-121
The factors that create a habitable planet are considered at all scales, from planetary inventories to micro-habitats in soft
sediments and intangibles such as habitat linkage. The possibility of habitability first comes about during accretion, as
a product of the processes of impact and volatile inventory history. To create habitability water is essential, not only for
life but to aid the continual tectonic reworking and erosion that supply key redox contrasts and biochemical substrates to
sustain habitability. Mud or soft sediment may be a biochemical prerequisite, to provide accessible substrate and protection.
Once life begins, the habitat is widened by the activity of life, both by its management of the greenhouse and by partitioning
reductants (e.g. dead organic matter) and oxidants (including waste products). Potential Martian habitats are discussed: by
comparison with Earth there are many potential environmental settings on Mars in which life may once have occurred, or may
even continue to exist. The long-term evolution of habitability in the Solar System is considered. 相似文献
280.
The links between Earth and space exploration occur across a broad spectrum, from the use of satellite technology to support environmental monitoring and habitat protection to the study of extreme environments on Earth to prepare for the exploration of other planets. Taking the view that Earth and space exploration are part of a mutually beneficial continuum is in contrast to the more traditionally segregated view of these areas of activity. In its most polarized manifestation, space exploration is regarded as a waste of money, distracting from solving problems here at home, while environmental research is seen to be introspective, distracting from expansive visions of exploring the frontier of space. The Earth and Space Foundation was established in 1994 to help further mutually beneficial links by funding innovative field projects around the world that work at the broad interface between environmental and space sciences, thus encouraging the two communities to work together to solve the challenges facing society. This paper describes the work of the foundation and the philosophy behind its programmes. 相似文献