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1.
The article discusses the history of the development and experimental testing of the automatic self-propelled chassis Lunokhod-1 and the scientific and technical problems that were solved in the course of this work. The reaction of scientists and the world community to the first studies of the lunar surface using an automatic mobile laboratory is discussed.  相似文献   

2.
An analysis is performed of 91 panoramic photographs taken by Lunokhod-1 and -2, 17 panoramic images composed of photographs taken by Apollo 11–15 astronauts, and six LROC NAC photographs. The results are used to measure the height-to-visible-diameter (h/d) and height-to-maximum-diameter (h/D) ratios for lunar rocks at three highland and three mare sites on the Moon. The average h/d and h/D for the six sites are found to be indistinguishable at a significance level of 95%. Therefore, our estimates for the average h/d = 0.6 ± 0.03 and h/D = 0.54 ± 0.03 on the basis of 445 rocks are applicable for the entire Moon’s surface. Rounding off, an h/D ratio of ≈0.5 is suggested for engineering models of the lunar surface. The ratios between the long, medium, and short axes of the lunar rocks are found to be similar to those obtained in high-velocity impact experiments for different materials. It is concluded, therefore, that the degree of penetration of the studied lunar rocks into the regolith is negligible, and micrometeorite abrasion and other factors do not dominate in the evolution of the shape of lunar rocks.  相似文献   

3.
From the lunar surface survey performed with a narrow-angle camera of the Lunar Reconnaissance Orbiter (LRO) spacecraft, the distributions of the phase ratios of the Apollo 11 and 12 landing sites and the Ranger 9 impact site were mapped. In the acquired images, the traces of the structural disturbances of the lunar regolith layer caused by the jet flows are seen. In the Ranger 9 impact site, one can see the crater of about 15 m across with a ray system, which is hardly noticeable in the brightness picture, but has a high contract in the phase ratio picture. The character of the photometric anomaly of the rays of this crater shows that they are formed by the ejected stones composing the rugged relief, which induces a strong shadow effect. At the same time, the influence of jet flows from the rocket engines smooths the relief and leads to the photometric anomaly of the opposite sign. The estimate of the maturity degree of the lunar regolith in the Apollo 11 and 12 landing sites obtained from the SELENE spectral survey suggests that the depth of the influence of the rocket engines on the soil is small, and the surface of the impact crater formed by the Ranger 9 spacecraft contains a large amount of the immature soil.  相似文献   

4.
Through the example of comparison of the natural features of two regions in the northern part of Mare Imbrium, that were directly investigated in detail with remotely controlled rovers on the lunar surface, the capabilities of combining orbital remote measurements of the physical and mechanical properties and the chemical composition of the lunar soil with their direct measurements have been shown. From the remotely determined spectropolarimetric and gamma-spectrometric characteristics of the regolith surface layer, the exposure age (the maturity), the mean effective size of particles of the fine fraction, the absolute age of the formations, and the iron content in the soil were estimated. To compare the characteristics of the considered regions, the results of the investigations carried out directly on the lunar surface by the Lunokhod-1 rover and the analogous vehicle Yutu were used.  相似文献   

5.
Physical conditions in the near-surface layer of the Moon are overviewed. This medium is formed in the course of the permanent micrometeoroid bombardment of the lunar regolith and due to the exposure of the regolith to solar radiation and high-energy charged particles of solar and galactic origin. During a considerable part of a lunar day (more than 20%), the Moon is passing through the Earth’s magnetosphere, where the conditions strongly differ from those in the interplanetary space. The external effects on the lunar regolith form the plasma-dusty medium above the lunar surface, the so-called lunar exosphere, whose characteristic altitude may reach several tens of kilometers. Observations of the near-surface dusty exosphere were carried out with the TV cameras onboard the landers Surveyor 5, 6, and 7 (1967–1968) and with the astrophotometer of Lunokhod-2 (1973). Their results showed that the near-surface layer glows above the sunlit surface of the Moon. This was interpreted as the scattering of solar light by dust particles. Direct detection of particles on the lunar surface was made by the Lunar Ejects and Meteorite (LEAM) instrument deployed by the Apollo 17 astronauts. Recently, the investigations of dust particles were performed by the Lunar Atmosphere and Dust Environment Explorer (LADEE) instrument at an altitude of several tens of kilometers. These observations urged forward the development of theoretical models for the lunar exosphere formation, and these models are being continuously improved. However, to date, many issues related to the dynamics of dust and the near-surface electric fields remain unresolved. Further investigations of the lunar exosphere are planned to be performed onboard the Russian landers Luna-Glob and Luna-Resurs.  相似文献   

6.
An accurate determination of the landing trajectory of Chang'e-3(CE-3)is significant for verifying orbital control strategy, optimizing orbital planning, accurately determining the landing site of CE-3 and analyzing the geological background of the landing site. Due to complexities involved in the landing process, there are some differences between the planned trajectory and the actual trajectory of CE-3. The landing camera on CE-3 recorded a sequence of the landing process with a frequency of 10 frames per second. These images recorded by the landing camera and high-resolution images of the lunar surface are utilized to calculate the position of the probe, so as to reconstruct its precise trajectory. This paper proposes using the method of trajectory reconstruction by Single Image Space Resection to make a detailed study of the hovering stage at a height of 100 m above the lunar surface. Analysis of the data shows that the closer CE-3 came to the lunar surface, the higher the spatial resolution of images that were acquired became, and the more accurately the horizontal and vertical position of CE-3 could be determined. The horizontal and vertical accuracies were7.09 m and 4.27 m respectively during the hovering stage at a height of 100.02 m. The reconstructed trajectory can reflect the change in CE-3's position during the powered descent process. A slight movement in CE-3 during the hovering stage is also clearly demonstrated. These results will provide a basis for analysis of orbit control strategy,and it will be conducive to adjustment and optimization of orbit control strategy in follow-up missions.  相似文献   

7.
Wenzhe Fa 《Icarus》2010,207(2):605-615
In China’s first lunar exploration project, Chang-E 1 (CE-1), a multi-channel microwave radiometer was aboard the satellite, with the purpose of measuring microwave brightness temperature (Tb) from lunar surface and surveying the global distribution of lunar regolith layer thickness. In this paper, the primary 621 tracks of swath data measured by CE-1 microwave radiometer from November 2007 to February 2008 are collected and analyzed. Using the nearest neighbor interpolation to collect the Tb data under the same Sun illumination, global distributions of microwave brightness temperature from lunar surface at lunar daytime and nighttime are constructed. Based on the three-layer media modeling (the top dust-soil, regolith and underlying rock media) for microwave thermal emission of lunar surface, the CE-1 measured Tb and its dependence upon latitude, frequency and FeO + TiO2 content, etc. are discussed. The CE-1 Tb data at Apollo landing sites are especially chosen for validation and calibration on the basis of available ground measurements. Using the empirical dependence of physical temperature upon the latitude verified by the CE-1 multi-channel Tb data at Apollo landing sites, the global distribution of regolith layer thickness is further inverted from the CE-1 brightness temperature data at 3 GHz channel. Those inversions at Apollo landing sites and the characteristics of regolith layer thickness for lunar maria are well compared with the Apollo in situ measurements and the regolith thickness derived from the Earth-based radar data. Finally, the statistical distribution of regolith thickness is analyzed and discussed.  相似文献   

8.
Areas of lunar surface magnetic field are observed to ‘mirror’ low energy electrons present in the normal lunar space environment. The ambient electrons provide, in effect, a probe along the ambient magnetic field lines down to the lunar surface for remote sensing of the presence of surface fields. This probe, unlike direct measurement by the magnetometer, does not require low altitude or a very stable (magnetotail) ambient field to provide a mapping of regions of occurrence of such fields. Use of the on-board vector magnetometer measurements of the ambient magnetic field orientation allows accurate projection of such mapping onto the lunar surface. Preliminary maps of the lunar surface magnetic areas underlying the orbit of the ‘Particles and Fields Satellite deployed from Apollo-16’ have been generated, obtaining 40% coverage from partial data to demonstrate feasibility of the technique. As well as providing independent verification of areas such as Van de Graaff already discovered in the magnetometer data, these maps reveal many previously unreported areas of surface magnetism. The method is sensitive to fields of less than 0.1γ at the surface. Application to the full body of available PFS-1 & 2 electron data is expected to provide complete mapping of the lunar surface for areas of magnetization up to latitudes of 35–40 deg. The surface field regions observed are generally due to sources smaller than 10–50 km in size, although many individual regions are often so close together as to give much larger regions of effectively continuous mirroring. Absence of consistent mirroring by any global field places an upper limit on the size of any net lunar dipole moment of less than 1010 γ km3. Much additional information regarding the magnetic regions can be obtained by correlated analysis of both the electron return and vector magnetometer measurements at orbital altitude, the two techniques providing each other with directly complimentary measurements at the satellite and along the ambient field lines to the surface.  相似文献   

9.
Chang'e-3 was China's first soft-landing lunar probe that achieved a successful roving exploration on the Moon. A topography camera functioning as the lander's "eye" was one of the main scientific payloads installed on the lander. It was composed of a camera probe, an electronic component that performed image compression, and a cable assembly. Its exploration mission was to obtain optical images of the lunar topography in the landing zone for investigation and research. It also observed rover movement on the lunar surface and finished taking pictures of the lander and rover. After starting up successfully, the topography camera obtained static images and video of rover movement from different directions, 360?panoramic pictures of the lunar surface around the lander from multiple angles, and numerous pictures of the Earth. All images of the rover, lunar surface, and the Earth were clear, and those of the Chinese national flag were recorded in true color. This paper describes the exploration mission, system design, working principle, quality assessment of image compression, and color correction of the topography camera. Finally, test results from the lunar surface are provided to serve as a reference for scientific data processing and application.  相似文献   

10.
The establishment of a lunar control network is one of the core tasks in selenodesy, in which defining an absolute control point on the Moon is the most important step. However, up to now, the number of absolute control points has been very sparse. These absolute control points have mainly been lunar laser ranging retroreflectors, whose geographical location can be observed by observations on Earth and also identified in high resolution lunar satellite images. The Chang'e-3(CE-3) probe successfully landed on the Moon, and its geographical location has been monitored by an observing station on Earth. Since its positional accuracy is expected to reach the meter level, the CE-3 landing site can become a new high precision absolute control point. We use a sequence of images taken from the landing camera, as well as satellite images taken by CE-1 and CE-2, to identify the location of the CE-3 lander. With its geographical location known, the CE-3 landing site can be established as a new absolute control point, which will effectively expand the current area of the lunar absolute control network by 22%, and can greatly facilitate future research in the field of lunar surveying and mapping, as well as selenodesy.  相似文献   

11.
Data relevant to the shallow structure of the Moon obtained at the Apollo seismic stations are compared with previously published results of the active seismic experiments. It is concluded that the lunar surface is covered by a layer of low seismic velocity (V p ? 100 m s?1), which appears to be equivalent to the lunar regolith defined previously by geological observations. This layer is underlain by a zone of distinctly higher seismic velocity at all of the Apollo landing sites. The regolith thicknesses at the Apollo 11, 12, and 15 sites are estimated from the shear-wave resonance to be 4.4, 3.7, and 4.4 m, respectively. These thicknesses and those determined at the other Apollo sites by the active seismic experiments appear to be correlated with the age determinations and the abundances of extralunar components at the sites.  相似文献   

12.
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13.
We describe the future SMART-1 European Space Mission whose objective is to study the lunar surface from a polar lunar orbit. In particular, it is anticipated that selected regions of the Moon will be photographed using the AMIE camera with a mean spatial resolution of about 100 m in three spectral channels (0.75, 0.92, and 0.96 m) over a wide range of phase angles. Since these spectral channels and the AMIE resolution are close to those of the UVVIS camera onboard the Clementine spacecraft, the simultaneous processing of SMART-1 and Clementine data can be planned, for example, to obtain phase-ratio images. These images carry information on the structural features of the lunar surface. In particular, UVVIS/Clementine data revealed a photometric anomaly at the Apollo-15 landing site associated with the blowing of the lunar regolith by the lander engine. Anomalies were found in the ejection zones of several fresh craters.  相似文献   

14.
The paper presents estimates of the occurrence probability of slopes, whose steep surfaces could be dangerous for the landing of the Luna-Glob descent probe (Luna-25) given the baseline of the span between the landing pads (~3.5 m), for five potential landing ellipses. As a rule, digital terrain models built from stereo pairs of high-resolution images (here, the images taken by the Narrow Angle Camera onboard the Lunar Reconnaissance Orbiter (LROC NAC)) are used in such cases. However, the planned landing sites are at high latitudes (67°–74° S), which makes it impossible to build digital terrain models, since the difference in the observation angle of the overlapping images is insufficient at these latitudes. Because of this, to estimate the steepness of slopes, we considered the interrelation between the shaded area percentage in the image and the Sun angle over horizon at the moment of imaging. For five proposed landing ellipses, the LROC NAC images (175 images in total) with a resolution from 0.4 to 1.2 m/pixel were analyzed. From the results of the measurements in each of the ellipses, the dependence of the shaded area percentage on the solar angle were built, which was converted to the occurrence probability of slopes. For this, the data on the Apollo 16 landing region ware used, which is covered by both the LROC NAC images and the digital terrain model with high resolution. As a result, the occurrence probability of slopes with different steepness has been estimated on the baseline of 3.5 m for five landing ellipses according to the steepness categories of <7°, 7°–10°, 10°–15°, 15°–20°, and >20°.  相似文献   

15.
Juxtaposing images of the surface of Titan made by the Huygens probe and photos of the mud volcano region on Earth (the Taman peninsula, the Caucasus) reveals similar geomorphologic features. This has led us to suggest the existence of cryogenic mud-volcanic activity on Titan. The role of liquid methane in supporting this process on Titan can be the same as that of gaseous methane on Earth. For Titan, gas hydrates (hydrates of hydrocarbon gases) and water ice are analogs of terrestrial clay breccia. Note that gas hydrates are stable at P-T conditions typical of Titan. Assuming the existence of mud-volcanic activity on Titan allows us to explain: (i) the general view of the landscape near the Huygens probe landing site, (ii) the chains of bright “islets” noticed during the probe descent, which may be a marker of a tectonic fault line, (iii) the conic shape of the hill in the foreground of the image taken from an altitude of 8 km, (iv) the rounded pebble-like shape of the small solid blocks on the surface of Titan, and (v) the presence of long white strips, each of which seems to diverge at one of the ends (such a picture can be produced by methane wind carrying away the ejecta of a gaseous volcano from its crater).  相似文献   

16.
Apollo 12 Lunar Module exhaust plume impingement on Lunar Surveyor III   总被引：1，自引：0，他引：1  
Understanding plume impingement by retrorockets on the surface of the Moon is paramount for safe lunar outpost design in NASA’s planned return to the Moon for the Constellation Program. Visual inspection, Scanning Electron Microscopy, and surface scanned topology have been used to investigate the damage to the Lunar Surveyor III spacecraft that was caused by the Apollo 12 Lunar Module’s close proximity landing. Two parts of the Surveyor III craft returned by the Apollo 12 astronauts, Coupons 2050 and 2051, which faced the Apollo 12 landing site, show that a fine layer of lunar regolith coated the materials and was subsequently removed by the Apollo 12 Lunar Module landing rocket. The coupons were also pitted by the impact of larger soil particles with an average of 103 pits/cm2. The average entry size of the pits was 83.7 μm (major diameter) × 74.5 μm (minor diameter) and the average estimated penetration depth was 88.4 μm. Pitting in the surface of the coupons correlates to removal of lunar fines and is likely a signature of lunar material imparting localized momentum/energy sufficient to cause cracking of the paint. Comparison with the lunar soil particle size distribution and the optical density of blowing soil during lunar landings indicates that the Surveyor III spacecraft was not exposed to the direct spray of the landing Lunar Module, but instead experienced only the fringes of the spray of soil. Had Surveyor III been exposed to the direct spray, the damage would have been orders of magnitude higher.  相似文献   

17.
The images of the southwestern part of the lunar disk showing the distributions of the negative polarization parameters of the light scattered by the lunar surface are presented. The distributions of the negative polarization minimum P min, the inversion angle αinv, and the polarization slope at the inversion point h significantly differ from the albedo image. This testifies to the fact that polarimetry yields independent information on the structure and optical properties of the lunar regolith.  相似文献   

18.
Phase-ratio imagery is a new tool of qualitative photometric analyses of the upper layer of the lunar regolith, which allows the identification of natural surface structure anomalies and artificially altered regolith. We apply phase-ratio imagery to analyze the Apollo-14, -15, and -17 landing sites. This reveals photometric anomalies of ∼170 × 120 m size that are characterized by lower values of the phase-function steepness, indicating a smoothing of the surface microstructure caused by the engine jets of the landing modules. Other photometric anomalies characterized by higher phase-function slopes are the result of regolith loosening by astronaut boots and the wheels of the Modular Equipment Transporter and the Lunar Roving Vehicle. We also provide a possible explanation for the high brightness of the wheel tracks seen in on-surface images acquired at very large phase angles.  相似文献   

19.
An origin of the Moon by a Giant Impact is presently the most widely accepted theory of lunar origin. It is consistent with the major lunar observations: its exceptionally large size relative to the host planet, the high angular momentum of the Earth–Moon system, the extreme depletion of volatile elements, and the delayed accretion, quickly followed by the formation of a global crust and mantle.According to this theory, an impact on Earth of a Mars-sized body set the initial conditions for the formation and evolution of the Moon. The impact produced a protolunar cloud. Fast accretion of the Moon from the dense cloud ensured an effective transformation of gravitational energy into heat and widespread melting. A “Magma Ocean” of global dimensions formed, and upon cooling, an anorthositic crust and a mafic mantle were created by gravitational separation.Several 100 million years after lunar accretion, long-lived isotopes of K, U and Th had produced enough additional heat for inducing partial melting in the mantle; lava extruded into large basins and solidified as titanium-rich mare basalt. This delayed era of extrusive rock formation began about 3.9 Ga ago and may have lasted nearly 3 Ga.A relative crater count timescale was established and calibrated by radiometric dating (i.e., dating by use of radioactive decay) of rocks returned from six Apollo landing regions and three Luna landing spots. Fairly well calibrated are the periods ≈4 Ga to ≈3 Ga BP (before present) and ≈0.8 Ga BP to the present. Crater counting and orbital chemistry (derived from remote sensing in spectral domains ranging from γ- and x-rays to the infrared) have identified mare basalt surfaces in the Oceanus Procellarum that appear to be nearly as young as 1 Ga. Samples returned from this area are needed for narrowing the gap of 2 Ga in the calibrated timescale. The lunar timescale is not only used for reconstructing lunar evolution, but it serves also as a standard for chronologies of the terrestrial planets, including Mars and possibly early Earth.The Moon holds a historic record of Galactic cosmic-ray intensity, solar wind composition and fluxes and composition of solids of any size in the region of the terrestrial planets. Some of this record has been deciphered. Secular mixing of the Sun was constrained by determining 3He/4He of solar wind helium stored in lunar fines and ancient breccias. For checking the presumed constancy of the impact rate over the past ≈3.1 Ga, samples of the youngest mare basalts would be needed for determining their radiometric ages.Radiometric dating and stratigraphy has revealed that many of the large basins on the near side of the Moon were created by impacts about 4.1 to 3.8 Ga ago. The apparent clustering of ages called “Late Heavy Bombardment (LHB)” is thought to result from migration of planets several 100 million years after their accretion.The bombardment, unexpectedly late in solar system history, must have had a devastating effect on the atmosphere, hydrosphere and habitability on Earth during and following this epoch, but direct traces of this bombardment have been eradicated on our planet by plate tectonics. Indirect evidence about the course of bombardment during this epoch on Earth must therefore come from the lunar record, especially from additional data on the terminal phase of the LHB. For this purpose, documented samples are required for measuring precise radiometric ages of the Orientale Basin and the Nectaris and/or Fecunditatis Basins in order to compare these ages with the time of the earliest traces of life on Earth.A crater count chronology is presently being built up for planet Mars and its surface features. The chronology is based on the established lunar chronology whereby differences between the impact rates for Moon and Mars are derived from local fluxes and impact energies of projectiles. Direct calibration of the Martian chronology will have to come from radiometric ages and cosmic-ray exposure ages measured in samples returned from the planet.  相似文献   

20.
We present X-ray fluorescence observations of the lunar surface, made by the Chandrayaan-1 X-ray Spectrometer during two solar flare events early in the mission (12th December 2008 and 10th January 2009). Modelling of the X-ray spectra with an abundance algorithm allows quantitative estimates of the MgO/SiO2 and Al2O3/SiO2 ratios to be made for the two regions, which are in mainly basaltic areas of the lunar nearside. One of these ground tracks includes the Apollo 14 landing site on the Fra Mauro Formation. Within the 1σ errors provided, the results are inside the range of basaltic samples from the Apollo and Luna collections. The Apollo 14 soil composition is in agreement with the results from the January flare at the 1σ uncertainty level. Discrepancies are observed between our results and compositions derived for the same areas by the Lunar Prospector gamma-ray spectrometer; some possible reasons for this are discussed.  相似文献   

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