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1.
Accurate Mars Express orbits to improve the determination of the mass and ephemeris of the Martian moons 总被引：1，自引：0，他引：1
P. Rosenblatt V. Lainey S. Le Maistre J.C. Marty V. Dehant M. Ptzold T. Van Hoolst B. Husler 《Planetary and Space Science》2008,56(7):1043-1053
The determination of the ephemeris of the Martian moons has benefited from observations of their plane-of-sky positions derived from images taken by cameras onboard spacecraft orbiting Mars. Images obtained by the Super Resolution Camera (SRC) onboard Mars Express (MEX) have been used to derive moon positions relative to Mars on the basis of a fit of a complete dynamical model of their motion around Mars. Since, these positions are computed from the relative position of the spacecraft when the images are taken, those positions need to be known as accurately as possible. An accurate MEX orbit is obtained by fitting two years of tracking data of the Mars Express Radio Science (MaRS) experiment onboard MEX. The average accuracy of the orbits has been estimated to be around 20–25 m. From these orbits, we have re-derived the positions of Phobos and Deimos at the epoch of the SRC observations and compared them with the positions derived by using the MEX orbits provided by the ESOC navigation team. After fit of the orbital model of Phobos and Deimos, the gain in precision in the Phobos position is roughly 30 m, corresponding to the estimated gain of accuracy of the MEX orbits. A new solution of the GM of the Martian moons has also been obtained from the accurate MEX orbits, which is consistent with previous solutions and, for Phobos, is more precise than the solution from the Mars Global Surveyor (MGS) and Mars Odyssey (ODY) tracking data. It will be further improved with data from MEX-Phobos closer encounters (at a distance less than 300 km). This study also demonstrates the advantage of combining observations of the moon positions from a spacecraft and from the Earth to assess the real accuracy of the spacecraft orbit. In turn, the natural satellite ephemerides can be improved and participate to a better knowledge of the origin and evolution of the Martian moons. 相似文献
2.
Jürgen Oberst Valéry Lainey Christophe Le Poncin-Lafitte Veronique Dehant Pascal Rosenblatt Stephan Ulamec Jens Biele J?rn Spurmann Ralph Kahle Volker Klein Ulrich Schreiber Anja Schlicht Nicolas Rambaux Philippe Laurent Beno?t Noyelles Bernard Foulon Alexander Zakharov Leonid Gurvits Denis Uchaev Scott Murchie Cheryl Reed Slava G. Turyshev Jesus Gil Mariella Graziano Konrad Willner Kai Wickhusen Andreas Pasewaldt Marita W?hlisch Harald Hoffmann 《Experimental Astronomy》2012,34(2):243-271
GETEMME (Gravity, Einstein??s Theory, and Exploration of the Martian Moons?? Environment), a mission which is being proposed in ESA??s Cosmic Vision program, shall be launched for Mars on a Soyuz Fregat in 2020. The spacecraft will initially rendezvous with Phobos and Deimos in order to carry out a comprehensive mapping and characterization of the two satellites and to deploy passive Laser retro-reflectors on their surfaces. In the second stage of the mission, the spacecraft will be transferred into a lower 1500-km Mars orbit, to carry out routine Laser range measurements to the reflectors on Phobos and Deimos. Also, asynchronous two-way Laser ranging measurements between the spacecraft and stations of the ILRS (International Laser Ranging Service) on Earth are foreseen. An onboard accelerometer will ensure a high accuracy for the spacecraft orbit determination. The inversion of all range and accelerometer data will allow us to determine or improve dramatically on a host of dynamic parameters of the Martian satellite system. From the complex motion and rotation of Phobos and Deimos we will obtain clues on internal structures and the origins of the satellites. Also, crucial data on the time-varying gravity field of Mars related to climate variation and internal structure will be obtained. Ranging measurements will also be essential to improve on several parameters in fundamental physics, such as the Post-Newtonian parameter ?? as well as time-rate changes of the gravitational constant and the Lense-Thirring effect. Measurements by GETEMME will firmly embed Mars and its satellites into the Solar System reference frame. 相似文献
3.
Because of the absence of the atmosphere, the short duration of the Phobos day (7.7 hours), and the presence of a highly porous and fine-grained soil on the Phobos surface, all components of the future Russian Fobos–Grunt lander will operate under frequent and sharp temperature changes: from positive to extremely low negative temperatures. As a consequence, information about the temperature regime directly on the surface of the Martian satellite and in the near-surface layer appears to be extremely important. The proposed publication contains both the information about the thermophysical properties of the surface regolith of Phobos, derived from observations made with the Mariner 9 orbiter, the Viking orbiter, the Fobos-2 spacecraft, and the Mars Global Surveyor orbiter, and the results of the numerical modeling of the thermal regime of the surface regolith layer (on diurnal and seasonal time scales) in the area of the potential Fobos–Grunt landing site. We performed this modeling by taking into account the seasons on Mars and the effects due to the eclipse of Phobos by Mars. 相似文献
4.
M. Ya. Marov 《Solar System Research》2010,44(1):1-4
The Phobos-Soil project, based on a new generation of spacecraft, is aimed at the study of Phobos, one of the Martian moons.
The main goal of the project is to bring soil samples from the surface of Phobos to the Earth for a scrutinized analysis of
the relic matter collected on one of the Solar System’s minor bodies. The project is considered to be a step in the long-scale
extensive quest for data on planets, comets, asteroids, and solving a vast number of other theoretical and applied problems. 相似文献
5.
O. I. Korablev A. V. Grigor’ev B. E. Moshkin L. V. Zasova F. Montmessin A. B. Gvozdev V. N. Shashkin D. V. Patsaev V. S. Makarov S. V. Maksimenko N. I. Ignatiev A. A. Fedorova G. Arnold A. V. Shakun A. I. Terentiev A. V. Zharkov B. S. Mayorov Yu. V. Nikol’sky I. V. Khatuntsev G. Bellucci M. Giuranna R. O. Kuz’min A. V. Rodin 《Solar System Research》2012,46(1):31-40
An AOST Fourier spectrometer of the Phobos-Soil project is intended for studying Mars and Phobos by means of measurements of IR radiation spectra of the Martian surface and atmosphere, the Phobos surface, and the spectrum of solar radiation passing through the Martian atmosphere on its limb. The main scientific problems to be solved with the spectrometer on Mars are measurements of methane content, search for minor constituents, and study of diurnal variations in the temperature and atmospheric aerosol. The spectrometer will also study the Martian and Phobos surface both remotely and after landing. The spectral range of the instrument is 2.5?C25 ??m, the best spectral resolution (without apodization) is 0.6 cm?1, and the instantaneous field of view is 2.5°. The recording time of one spectrum is equal to 5 s in solar observations and 50 s in observations of Mars and Phobos. The instrument has self-thermal stabilization and two-axis pointing systems, as well as a built-in radiation source for flight calibration. The spectrometer mass is 4 kg, and power consumption is up to 13 W. Scientific problems, measurement modes, and, briefly, engineering implementation of the experiment are discussed in this work. 相似文献
6.
The paper contains the data on the thermal and physical characteristic of the surface regolith of the Martian satellite Phobos obtained from the spaceborne remote sensing (with the Mariner 9, Viking, and Mars Global Surveyor orbiters and the Phobos-2 spacecraft) and the results of the numerical modeling of the thermal regime in the surface regolith (on diurnal and seasonal scales) performed for the prospective landing site in the Lagado Planitia region located in the anti-Martian hemisphere of Phobos. 相似文献
7.
O. I. Korablev A. V. Bondarenko I. V. Dokuchaev A. Yu. Ivanov O. E. Kozlov V. A. Kottsov A. B. Kiselev J. -P. Bibring J. -J. Fourmond 《Solar System Research》2010,44(5):403-408
Microscopy and spectroscopy are important methods of studies. The use of a microscope onboard a spacecraft is connected with
the fact that the closer approach to the objects and the switch to the in situ measurement methods have become possible. The
combination of taking an image and performing a spectral analysis forms a new type of instrument, so-called videospectrometers.
The scientific payload of the Phobos-Grunt spacecraft includes the microscope spectrometer designed to analyze the composition of the surface regolith of Phobos in
detail. 相似文献
8.
Recent Viking results indicate the Martian satellites are composed of carbonaceous chondritic material, suggesting that Phobos and Deimos were once asteroids captured by Mars. On the other hand, the low eccentricities and inclinations of their orbits on the equator of Mars argue against that hypothesis. This paper presents detailed calculations of the tidal evolution of Phobos and Deimos, considering dissipation in both Mars and its satellites simultaneously and using a new method applicable for any value of the eccentricity. In particular, including precession of the satellites' orbits indicates that they have always remained close to their Laplacian plane, so that the orbital planes of Phobos and Deimos switched from near the Martian orbital plane to the Martian equator once the perturbations due to the planetary oblateness dominated the solar perturbations, as they do presently. The results show that Deimos has been little affected by tides, but several billion (109) years ago, Phobos was in a highly eccentric orbit lying near the common plane of the solar system. This outcome is obtained for very reasonable values of dissipation inside Mars and inside Phobos. Implications for the origin of the Martian satellites are discussed. 相似文献
9.
Rosenqvist J Drossart P Combes M Encrenaz T Lellouch E Bibring JP Erard S Langevin Y Chassefiere E 《Icarus》1992,98(2):254-270
Global Martian atmospheric results derived from the infrared imaging spectrometer ISM flown aboard the Phobos 2 Soviet spacecraft are presented. Over low altitude regions the expected CO mixing ratio of (8 +/- 3) x 10(-4) is measured. Variations of the 2.35-micrometers feature are inconsistent with this value over the Great Martian Volcanoes. If the 2.35-micrometers band is entirely attributable to carbon monoxide, the CO mixing ratio is typically depleted by a factor of 3 over these high altitude areas. Orography should play a major role in the existence of this CO "hole." If, however, these spectral variations at 2.35 micrometers are due to the surface composition, the fraction of the surface covered by the responsible mineral must smoothly decrease as the surface elevation decreases. This phenomenon implies a strong interaction between the surface and the atmosphere for the Great Martian Volcanoes. Diurnal behavior and latitudinal variations of water vapor are globally consistent with Viking measurements. During the Phobos observations, the water vapor amounts over the bright equatorial regions range around 11 pr-micrometers during the day. These amounts are slightly larger than those inferred from 1976 to 1979. The lack of global dust storms during 1988-1989 could explain the enhancement of H2O in the atmosphere. 相似文献
10.
This paper shortly describes the selection technique for the landing sites of the Phobos-Soil spacecraft, the characteristics of the Phobos relief, the history of choosing the potential landing sites in the process
of working on the project, and the suggestions to shift the landing sites to the region recently imaged by the Mars Express spacecraft with a high spatial resolution under favorable illumination conditions. 相似文献
11.
Using Mariner 9 results on the shapes, rotation periods and photometric functions of Phobos and Deimos we calculate approximate orbital lightcurves for the two Martian satellites. The prediction is that both Phobos and Deimos should show orbital brightness fluctuations detectable from Earth. For Phobos the detectable amplitude is predicted to be about 0.1 mag; for Deimos, 0.2 mag. 相似文献
12.
H. Rickman E. Słaby J. Gurgurewicz M. Śmigielski M. Banaszkiewicz J. Grygorczuk M. Morawski K. Seweryn R. Wawrzaszek 《Solar System Research》2014,48(4):279-286
CHOMIK is the name of a penetrator constructed for sampling and retrieval of Phobos surface material. It formed an integral part of the Phobos Sample Return Mission. In this paper we present its construction and intended mode of operation, since the concept is still viable for future missions either to Phobos or to other small bodies of similar dimensions. We take Phobos as an example to describe the science case for such an instrument and how it might be utilized to resolve important open issues regarding the origin of the Martian moons. Concerning the latter, we place emphasis on measurement techniques and analysis tools for mapping trace element concentrations in returned sample. 相似文献
13.
There are reasons to expect that Mars is surrounded by a region of dust, similar to rings, originating from the bombardment of Phobos and Deimos by meteroids. Using a simple radiative transfer model, we have investigated the angular distribution and the absolute values of the solar radiance scattered by such a dust region, to the purpose of assessing the possibilities and limitations of future photometric searches after the circummartian dust. Our model values of the number density of the dust grains in the space around Mars and of their size distribution have been derived from the results obtained by other authors. The single-scattering albedo of the dust grains has been deduced from the reflectance spectra of Phobos, taken by the spacecraft Phobos 2. Calculations, carried out for a few phenomenological phase functions, have shown that in the visible the radiance scattered by the rings is well within the detectability range of a modern sensible photometer, so that the prospectives for photometric search for the Martian dust rings are optimistic. Furthermore, our results confirm that the dust region could not be observed by the Viking cameras and this supports o our assumptions regarding the optical properties of the circummartian grains. 相似文献
14.
V. A. Shishov 《Solar System Research》2008,42(4):319-328
For the needs of the upcoming flight to Phobos within the framework of the project Phobos-Grunt, a dynamical numerical theory of the motion of Phobos is developed on the basis of Earth-based and spacecraft (SC) optical measurements and Earth-based radio observations of the SC motion. The theory uses the most reliable astronomical constants. Within the framework of a unified dynamical model, an algorithm is proposed for the joint correction of Phobos and the spacecraft parameters of motion, among which are the secular acceleration of Phobos and its gravitational constant. The accuracy of the obtained ephemeris is estimated for the time of the SC arrival to Phobos. 相似文献
15.
Linkin V Harri AM Lipatov A Belostotskaja K Derbunovich B Ekonomov A Khloustova L Kremnev R Makarov V Martinov B Nenarokov D Prostov M Pustovalov A Shustko G Jarvinen I Kivilinna H Korpela S Kumpulainen K Lehto A Pellinen R Pirjola R Riihela P Salminen A Schmidt W McKay CP 《Planetary and Space Science》1998,46(6-7):717-737
A mission to Mars including two Small Stations, two Penetrators and an Orbiter was launched at Baikonur, Kazakhstan, on 16 November 1996. This was called the Mars-96 mission. The Small Stations were expected to land in September 1997 (Ls approximately 178 degrees), nominally to Amazonis-Arcadia region on locations (33 N, 169.4 W) and (37.6 N, 161.9 W). The fourth stage of the Mars-96 launcher malfunctioned and hence the mission was lost. However, the state of the art concept of the Small Station can be applied to future Martian lander missions. Also, from the manufacturing and performance point of view, the Mars-96 Small Station could be built as such at low cost, and be fairly easily accommodated on almost any forthcoming Martian mission. This is primarily due to the very simple interface between the Small Station and the spacecraft. The Small Station is a sophisticated piece of equipment. With the total available power of approximately 400 mW the Station successfully supports an ambitious scientific program. The Station accommodates a panoramic camera, an alpha-proton-x-ray spectrometer, a seismometer, a magnetometer, an oxidant instrument, equipment for meteorological observations, and sensors for atmospheric measurement during the descent phase, including images taken by a descent phase camera. The total mass of the Small Station with payload on the Martian surface, including the airbags, is only 32 kg. Lander observations on the surface of Mars combined with data from Orbiter instruments will shed light on the contemporary Mars and its evolution. As in the Mars-96 mission, specific science goals could be exploration of the interior and surface of Mars, investigation of the structure and dynamics of the atmosphere, the role of water and other materials containing volatiles and in situ studies of the atmospheric boundary layer processes. To achieve the scientific goals of the mission the lander should carry a versatile set of instruments. The Small Station accommodates devices for atmospheric measurements, geophysical and geochemical studies of the Martian surface and interior, and cameras for descent phase and panoramic views. These instruments would be able to contribute remarkably to the process of solving some of the scientific puzzles of Mars. 相似文献
16.
M. Ya. Marov A. V. Kolesnichenko K. K. Manuilov V. P. Osipov 《Solar System Research》2010,44(5):393-402
The methodology and the main features of the Thermophob experiment developed for the direct analysis of the thermophysical
properties of the surface of the Martian satellite Phobos from the Phobos-Grunt lander are considered. The methodical and engineering aspects of the measurements are discussed, and the design of the instrument
and the potential of the interpretation of the measurement results with accounting for the theoretical estimates and the data
of the laboratory tests are discussed. 相似文献
17.
Several of the most fundamental and feasible geophysical problems partially related to the Phobos-Grunt mission have been analyzed based on the available works. The assumed results will form the informational basis for the development
of the cosmogony of planets’ small satellites and asteroids. Correspondingly, the aims of the experiment are to study the
internal structure and energy state of Phobos; to analyze the manifestation of pulsed effects and fields, including the registration
of seismic signals and wave fields of Phobos; and to measure the long-period oscillations on the surface of Phobos in the
range of 10−5–10 Hz. Studying Phobos gives an example of specific problems peculiar to small bodies of the Solar System: specific features
of cratering, grooves, and morphological structures. The registration of gas-dust streams extends the knowledge of the space-time
structure of the Solar System and its objects and processes and will confirm that stellar systems can constantly interact.
The physical principles of the registration of seismic fields and signals are briefly described, and the instrumental basis
for cosmogonic seismology is comparatively presented. It has been indicated that the piezoelectric and electrodynamic systems
of the desired signal registration complete each other, and it is desirable to use both systems if 2- and 3-D registration
systems are applied. The seismometric instrumentation of the Phobos spacecraft has been considered. The device’s physical characteristics, block diagrams, energy consumption, and information
content are presented. The seismoacoustic (HF) device unit and its advantages during the registration of very weak signals
owing to the use of the mechanical transformer effect are described in more detail. The seismic system created can ensure
the solution of the scientific problems of the mission to Phobos, including the study of the internal structure, origin, depth
structures, and external impacts of the field, corpuscular, and micrometeorite types. 相似文献
18.
This paper discusses an approach for designing missions to Phobos that do not require a critical maneuver in proximity of the moon. A low-energy transfer is designed that utilizes the aspherical mass distribution of Phobos to capture a spacecraft into a distant retrograde orbit (DRO) for the mission duration. The process for generating stable DROs in the Mars–Phobos system is discussed along with the method for generating and surveying a set of ballistic capture trajectories (BCTs) for DROs with altitudes between 0.5 and 14 km above Phobos. Statistical analysis of the BCT set reveals options for designing a mission to the desired DRO. This approach can be used in any three-body system when a significant perturbation is present, such as Phobos’ aspherical co-rotating gravity field. 相似文献
19.
I. L. Shevalev 《Solar System Research》2012,46(7):578-588
The article describes the life and creative activity of V.M. Kovtunenko, an outstanding creator of national rocket and space technology. Many research projects were implemented under his leadership in the Lavochkin Scientific and Production Association, such as the unmanned spacecraft to Venus, Mars, and small bodies in the solar system (Phobos and Halley??s comet), the first domestic extra-atmospheric astrophysical observatories Astron and Granat, interplanetary spacecraft of the new generation ??Phobos??, the first optoelectronic remote sensing system, the spacecraft Arkon-1, and a versatile booster unit Fregat. 相似文献
20.
A great many Martian bow shock and magnetic pile-up boundary crossings have been identified in the Phobos 2 and Mars Global Surveyor, MGS, data. From these observations the positions and shapes of the bow shock and magnetic pile-up boundary, MPB, have been derived and modelled, using curve-fitting techniques. The models thus derived separately from the Phobos 2 and MGS data sets do not differ drastically, despite the different time and space data coverages. The purpose of the paper is therefore to show the results obtained from the mixing of the Phobos 2 and MGS data bases and to compare the derived bow shock and MPB models with the ones obtained previously. The underlying objective was to see whether it was possible to determine improved bow shock and MPB models or not. The answer is definitely yes, and particularly for the MPB, thanks to the complementary nature of the observations. The boundaries crossed close to the subsolar direction or mostly far downstream by Phobos 2 indeed allow a better coverage of the Martian space environment to be considered. Nevertheless, in order to reduce the domination of the overabundant MGS data set and/or the crossings that are close to Mars (x>−4 RM, i.e. x>−13 562 km) weighting factors have been introduced. 相似文献