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1.
The results of a set of laboratory impact experiments (speeds in the range 1–5 km s−1) are reviewed. They are discussed in the context of terrestrial impact ejecta impacting the Moon and hence lunar astrobiology through using the Moon to learn about the history of life on Earth. A review of recent results indicates that survival of quite complex organic molecules can be expected in terrestrial meteorites impacting the lunar surface, but they may have undergone selective thermal processing both during ejection from the Earth and during lunar impact. Depending on the conditions of the lunar impact (speed, angle of impact etc.) the shock pressures generated can cause significant but not complete sterilisation of any microbial load on a meteorite (e.g. at a few GPa 1–0.1% of the microbial load can survive, but at 20 GPa this falls to typically 0.01–0.001%). For more sophisticated biological products such as seeds (trapped in rocks) the lunar impact speeds generate shock pressures that disrupt the seeds (experiments show this occurs at approximately 1 GPa or semi-equivalently 1 km s−1). Overall, the delivery of terrestrial material of astrobiological interest to the Moon is supported by these experiments, although its long term survival on the Moon is a separate issue not discussed here.  相似文献   

2.
Matija ?uk  Brett J. Gladman 《Icarus》2010,207(2):590-7225
Multiple impact basins formed on the Moon about 3.8 Gyr ago in what is known as the lunar cataclysm or Late Heavy Bombardment. Many workers currently interpret the lunar cataclysm as an impact spike primarily caused by main-belt asteroids destabilized by delayed planetary migration. We show that morphologically fresh (class 1) craters on the lunar highlands were mostly formed during the brief tail of the cataclysm, as they have absolute crater number density similar to that of the Orientale basin and ejecta blanket. The connection between class 1 craters and the cataclysm is supported by the similarity of their size-frequency distribution to that of stratigraphically-identified Imbrian craters. Majority of lunar craters younger than the Imbrium basin (including class 1 craters) thus record the size-frequency distribution of the lunar cataclysm impactors. This distribution is much steeper than that of main-belt asteroids. We argue that the projectiles bombarding the Moon at the time of the cataclysm could not have been main-belt asteroids ejected by purely gravitational means.  相似文献   

3.
The differences between the surface structure of the near side and the far side of the Moon have been topics of interest ever since photographs of the far side have been available. One recurrent hypothesis is that a large impact on the near side has deposited ejecta on the far side, resulting in thicker crust there. Specific proposals were made by P.H. Cadogan for the Gargantuan Basin and by E.A. Whitaker for the Procellarum Basin. Despite considerable effort, no consensus has been reached on the existence of these basins. The problem of searching for such a basin is one of finding its signature in a somewhat chaotic field of basin and crater impacts. The search requires a model of the topographic shape of an impact basin and its ejecta field. Such a model is described, based on elevation data of lunar basins collected by the Lidar instrument of the Clementine mission and crustal thickness data derived from tracking Clementine and other spacecraft. The parameters of the model are scaled according to the principles of dimensional analysis and isostatic compensation in the early Moon. The orbital dynamics of the ejecta and the curvature of the Moon are also taken into account. Using such a scaled model, a search for the best fit for a large basin led to identification of a basin whose cavity covers more than half the Moon, including the area of all of the impact basins visible on the near side. The center of this basin is at 22 degrees east longitude and 8.5 degrees north latitude and its average radius is approximately 3,160 km. It is a megabasin, a basin that contains other basins (the far side South Pole-Aitken Basin also qualifies for that designation). It has been called the Near Side Megabasin. Much of the material ejected from the basin escaped the Moon, but the remainder formed an ejecta blanket that covered all of the far side beyond the basin rim to a depth of from 6 to 30 km. Isostatic compensation reduced the depth relative to the mean surface to a range of 1–5 km, but the crustal thickness data reveals the full extent of the original ejecta. The elevation profile of the ejecta deposited on the far side, together with modification for subsequent impacts by known basins (especially the far side South Pole-Aitken Basin) matches the available topographic data to a high degree. The standard deviation of the residual elevations (after subtracting the model from the measured elevations) is about one-half of the standard deviation of the measured elevations. A section on implications discusses the relations of this giant basin to known variations in the composition, mineralogy, and elevations of different lunar terranes.  相似文献   

4.
A 1953 telescopic photograph of a flash on the Moon is the only unequivocal record of the rare crash of an asteroid-sized body onto the lunar surface. We estimate that this event would create an impact feature up to several km in size and that the diameter of the impacting body would be about 20 m. Such an event would cause regional devastation if it occurred on Earth. Although not detectable with ground- based telescopes, the lunar crater should be visible in space-based images of the Moon. A search of images from the Clementine mission reveals an ∼1.5-km high-albedo, blue, fresh-appearing crater with an associated ejecta blanket at the location of the flash. The identification of this crater offers an opportunity to investigate subsurface unaltered lunar soils.  相似文献   

5.
The National Aeronautics and Space Administration (NASA) continues to make progress toward long-term lunar habitation. Critical to the design of a lunar habitat is an understanding of the lunar surface environment. A subject for further definition is the lunar impact ejecta environment. The document NASA SP-8013 was developed for the Apollo program and is the latest definition of the ejecta environment. There is concern that NASA SP-8013 may over-estimate the lunar ejecta environment. NASA’s Meteoroid Environment Office (MEO) has initiated several tasks to improve the accuracy of our understanding of the lunar surface ejecta environment. This paper reports the results of experiments on projectile impact into powered pumice targets, simulating unconsolidated lunar regolith. The Ames Vertical Gun Range (AVGR) was used to accelerate spherical Pyrex projectiles of 0.29g to velocities ranging between 2.5 and 5.18 km/s. Impact on the pumice target occurred at normal incidence. The ejected particles were detected by thin aluminum foil targets placed around the pumice target in a 0.5 Torr vacuum. A simplistic technique to characterize the ejected particles was formulated. Improvements to this technique will be discussed for implementation in future tests.  相似文献   

6.
We report here on a survey of distal fine-grained ejecta deposits on the Moon, Mars, and Venus. On all three planets, fine-grained ejecta form circular haloes that extend beyond the continuous ejecta and other types of distal deposits such as run-out lobes or ramparts. Using Earth-based radar images, we find that lunar fine-grained ejecta haloes represent meters-thick deposits with abrupt margins, and are depleted in rocks ?1 cm in diameter. Martian haloes show low nighttime thermal IR temperatures and thermal inertia, indicating the presence of fine particles estimated to range from ∼10 μm to 10 mm. Using the large sample sizes afforded by global datasets for Venus and Mars, and a complete nearside radar map for the Moon, we establish statistically robust scaling relationships between crater radius R and fine-grained ejecta run-out r* for all three planets. On the Moon, r* ∼ R−0.18 for craters 5-640 km in diameter. For Venus, radar-dark haloes are larger than those on the Moon, but scale as r* ∼ R−0.49, consistent with ejecta entrainment in Venus’ dense atmosphere. On Mars, fine-ejecta haloes are larger than lunar haloes for a given crater size, indicating entrainment of ejecta by the atmosphere or vaporized subsurface volatiles, but scale as R−0.13, similar to the ballistic lunar scaling. Ejecta suspension in vortices generated by passage of the ejecta curtain is predicted to result in ejecta run-out that scales with crater size as R1/2, and the wind speeds so generated may be insufficient to transport particles at the larger end of the calculated range. The observed scaling and morphology of the low-temperature haloes leads us rather to favor winds generated by early-stage vapor plume expansion as the emplacement mechanism for low-temperature halo materials.  相似文献   

7.
It is known that most of the craters on the surface of the Moon were created by the collision of minor bodies of the Solar System. Main Belt Asteroids, which can approach the terrestrial planets as a consequence of different types of resonance, are actually the main responsible for this phenomenon. Our aim is to investigate the impact distributions on the lunar surface that low-energy dynamics can provide. As a first approximation, we exploit the hyberbolic invariant manifolds associated with the central invariant manifold around the equilibrium point L 2 of the Earth–Moon system within the framework of the Circular Restricted Three-Body Problem. Taking transit trajectories at several energy levels, we look for orbits intersecting the surface of the Moon and we attempt to define a relationship between longitude and latitude of arrival and lunar craters density. Then, we add the gravitational effect of the Sun by considering the Bicircular Restricted Four-Body Problem. In the former case, as main outcome, we observe a more relevant bombardment at the apex of the lunar surface, and a percentage of impact which is almost constant and whose value depends on the assumed Earth–Moon distance dEM. In the latter, it seems that the Earth–Moon and Earth–Moon–Sun relative distances and the initial phase of the Sun θ 0 play a crucial role on the impact distribution. The leading side focusing becomes more and more evident as dEM decreases and there seems to exist values of θ 0 more favorable to produce impacts with the Moon. Moreover, the presence of the Sun makes some trajectories to collide with the Earth. The corresponding quantity floats between 1 and 5 percent. As further exploration, we assume an uniform density of impact on the lunar surface, looking for the regions in the Earth–Moon neighbourhood these colliding trajectories have to come from. It turns out that low-energy ejecta originated from high-energy impacts are also responsible of the phenomenon we are considering.  相似文献   

8.
Abstract— The lunar surface is marked by at least 43 large and ancient impact basins, each of which ejected a large amount of material that modified the areas surrounding each basin. We present an analysis of the effects of basin formation on the entire lunar surface using a previously defined basin ejecta model. Our modeling includes several simplifying assumptions in order to quantify two aspects of basin formation across the entire lunar surface: 1) the cumulative amount of material distributed across the surface, and 2) the depth to which that basin material created a well‐mixed megaregolith. We find that the asymmetric distribution of large basins across the Moon creates a considerable nearside‐farside dichotomy in both the cumulative amount of basin ejecta and the depth of the megaregolith. Basins significantly modified a large portion of the nearside while the farside experienced relatively small degrees of basin modification following the formation of the large South Pole‐Aitken basin. The regions of the Moon with differing degrees of modification by basins correspond to regions thought to contain geochemical signatures remnant of early lunar crustal processes, indicating that the degree of basin modification of the surface directly influenced the distribution of the geochemical terranes observed today. Additionally, the modification of the lunar surface by basins suggests that the provenance of lunar highland samples currently in research collections is not representative of the entire lunar crust. Identifying locations on the lunar surface with unique modification histories will aid in selecting locations for future sample collection.  相似文献   

9.
The problem of the origin of the enigmatic tektites is still unsolved. The two leading hypotheses - viz., ejecta from terrestrial impacts, and ejecta from lunar volcanoes or lunar impacts, each encounters serious difficulties. The former has ballistic and water content difficulties, while the latter has some compositional difficulties, especially in the trace elements, as determined from the returned samples. It is possible that the latter problem may be met through lunar volcanic ejecta from sites suggesting more differentiation than the majority of the Moon. That such features may exist is suggested from the identity of some granitic material in the returned rocks and soil samples implying fairly sizable source regions on the Moon. The rare terrestrial strewn tektite fields require restrictive ballistic trajectories from the Moon. Calculations reveal that ellipses of varying, decreasing sizes which depend on velocity of vertical ejection from which ejecta will intersect the earth at low-entrance angles occur on the nearside of the Moon. Reasonable velocities were chosen (2.55 to 3.0 km s?1) and these ellipses circumscribe areas with longitudes between 30 and 50° east and latitudes between 7° north and south of the Moon's equator. These areas were searched for evidence of volcanism. As tektites have compositions ranging from acidic (major tektites) to basic (micro-tektites) contents of silica (SiO2) both acidic and basic volcanic features were sought. Since tektites range in age from about 30 million to 700000 yr old, they imply recent volcanism. Lunar Transient Phenomena (LTP) and data from various Apollo missions indicate that mild internal activity may still be occurring on the Moon. LTP sites are logical sources to investigate, of which four occur within the above delimited regions. These and their surroundings were examined and a number of possible explosive volcanism sites were found. These sites are identified and discussed after a review of the manifestations found from the various kinds of terrestrial volcanism for which lunar counterparts were sought.  相似文献   

10.
A model is proposed for the formation of lunar mascons which explains persistence of lunar mascons for more than 3 b.y., evidence for the volcanic activity 3.7-3.2 b.y. ago, and negative gravity anomalies surrounding the mascons. It is concluded that mascons have resulted from the perturbations introduced by the giant impacts into an otherwise spherically symmetric Moon; a giant impact enhances the rate of cooling beneath the impact site by introducing releatively low temperature to a deeper part of the Moon through forming a basin and also by removing substantial amount of radioactive material by means of ejecta. On the other hand, it reduces the rate of cooling beneath the surrounding highland by thermal insulation through extensive fracturing and covering by an ejecta blanketing. Consequently, the base of the lithosphere (100 km thick) beneath the highland remelts to a depth of about 80 km and this creates thermal stresses strong enough to open the fractures in the overlying region and to cause magmatization and volcanic activity. Persistence of the molten phase around 100 km depth for about 1 b.y. probably provides further differentiation and an upward concentration of low density material, giving rise to the observed negative gravity rings. On the other hand, the relatively cold lithosphere beneath the basin forms a layer strong enough to support the associated mascon.  相似文献   

11.
Despite evident similarities, the Argyre basin exhibits important differences with regard to its lunar counterparts, as the Orientale basin. These differences concern both the stratigraphy of the impact related units and the tectonics of these areas. The Argyre basin is not surrounded by ejecta with radial facies, but by an annulus of structurally uplifted and faulted preimpact basement. That is different from the lunar basins which exhibit a large annulus of radial facies but only a narrow ring of uplifted terrains. The Argyre basin is surrounded by five or more outer discontinuous rings extending far away from the basis edge. That is different from the lunar basins which are surrounded by only one, continuous and closer ring. These differences could be partially explained by the external conditions, but mainly by differences in the crustal properties and lithospheres thickness which would have been thinner on Mars than on the Moon.  相似文献   

12.
Microrater frequencies caused by fast (? 3 km s?1) ejecta have been determined using secondary targets in impact experiments. A primary projectile (steel sphere, diam 1.58 mm, mass 1.64 × 10?2 g) was shot in Duran glass with a velocity of 4.1 km s?1 by means of a light gas gun. The angular distribution of the secondary crater number densities shows a primary maximum around 25°, and a secondary maximum at about 60° from the primary target surface. The fraction of mass ejected at velocities of ? 3 km s?1 is only a factor of 7.5 × 10?5 of the primary projectile mass. A conservative calculation shows that the contribution of secondary microcraters (caused by fast ejecta) to primary microcrater densities on lunar rock surfaces (caused by interplanetary particles) is on the statistical average below 1% for any lunar surface orientation. Calculation of the interplanetary dust flux enhancement caused by Moon ejecta turned out to be in good agreement with Lunar Explorer 35in situ measurements.  相似文献   

13.
The Flux of Lunar Meteorites onto the Earth   总被引：1，自引：0，他引：1  
Numerous new finds of lunar meteorites in Oman allow detailed constraints to be obtained on the intensity of the transfer of lunar matter to the Earth. Our estimates show that the annual flux of lunar meteorites in the mass interval from 10 to 1000 g to the entire Earth's surface should not be less than several tenths of a kilogram and is more likely equal to tens or even a few hundred kilograms, i.e., a few percent of the total meteorite flux. This corresponds to several hundred or few thousand falls of lunar meteorites on all of Earth per year. Even small impact events, which produce smaller than craters on the Moon smaller than 10 km in diameter, are capable of transferring lunar matter to the Earth. In this case, the Earth may capture between 10 to 100% of the mass of high-velocity crater ejecta leaving the Moon. Our estimates for the lunar flux imply rather optimistic prospects for the discovery of new lunar meteorites and, consequently, for the analyses of the lunar crust composition. However, the meteorite-driven flux of lunar matter did not play any significant role in the formation of the material composition of the Earth's crust, even during the stage of intense meteorite bombardment.  相似文献   

14.
Abstract— Detailed investigations of the microimpact phenomena on Australasian microtektites from four samples from the Central Indian Basin reveal an array of features, such as very low-velocity captured droplets, welded projectiles, angular fragments and dust, craters generated by projectiles defining an oblique trajectory, high-velocity “pitless” craters, and the conventional hypervelocity craters with well-defined central pits and radial and concentric cracks—found commonly on lunar surface materials. The microimpacts are a consequence of interparticle collisions within the ejecta plume (as suggested by their chemistry) subsequent to a major impact and, therefore, reveal processes inherent in an impact-generated plume. All the impact phenomena observed here have taken place while the targets and projectiles were in flight and are therefore secondary impacts in lunar terms. However, some of the resultant features are analogous to lunar micro-craters attributed to primary impacts by cosmic dust. Therefore, ballistic sedimentation on the Moon is likely to contain plume collisional debris as well.  相似文献   

15.
The SMART-1 lunar impact   总被引：1，自引：0，他引：1  
The SMART-1 spacecraft impacted the Moon on 3rd September 2006 at a speed of 2 km s−1 and at a very shallow angle of incidence (∼1°). The resulting impact crater is too small to be viewed from the Earth; accordingly, the general crater size and shape have been determined here by laboratory impact experiments at the same speed and angle of incidence combined with extrapolating to the correct size scale to match the SMART-1 impact. This predicts a highly asymmetric crater approximately 5.5-26 m long, 1.9-9 m wide, 0.23-1.5 m deep and 0.71-6.9 m3 volume. Some of the excavated mass will have gone into crater rim walls, but 0.64-6.3 m3 would have been ejecta on ballistic trajectories corresponding to a cloud of 2200-21,800 kg of lunar material moving away from the impact site. The shallow Messier crater on the Moon is similarly asymmetric and is usually taken as arising from a highly oblique impact. The light flash from the impact and the associated ejecta plume were observed from Earth, but the flash magnitude was not obtained, so it is not possible to obtain the luminous efficiency of the impact event.  相似文献   

16.
3D simulations of basin-scale lunar impacts are carried out to investigate: (a) the origins of strong crustal magnetic fields and unusual terrain observed to occur in regions antipodal to young large basins; and (b) the origin of enhanced magnetic and geochemical anomalies along the northwest periphery of the South Pole-Aitken (SPA) basin. The simulations demonstrate that a basin-forming impact produces a massive, hot, partially ionized cloud of vapor and melt that expands thermally around the Moon, converging near the basin antipode approximately 1 h after the impact for typical impact parameters. In agreement with previous work, analytic calculations of the interaction of this vapor-melt cloud with an initial ambient magnetic field predict a substantial temporary increase in field intensity in the antipodal region. The time of maximum field amplification coincides with a period when impacting ejecta also converge near the antipode. The latter produce antipodal shock stresses within the range of 5-25 GPa where stable shock remanent magnetization (SRM) of lunar soils has been found experimentally to occur. Calculated antipodal ejecta thicknesses are only marginally sufficient to explain the amplitudes of observed magnetic anomalies if mean magnetization intensities are comparable to those produced experimentally. This suggests that pre-existing ejecta materials, which would also contain abundant metallic iron remanence carriers, may be important anomaly sources, a possibility that is consistent with enhanced magnetic anomalies observed peripheral to SPA. The latter anomalies may be produced by amplified secondary ejecta impact shock waves in the thick SPA ejecta mantle occurring near the antipodes of the Imbrium and Serenitatis impacts. Together with converging seismic compressional waves, these antipodal impact shocks may have produced especially deep fracture zones along the northwest edge of SPA near the Imbrium antipode, allowing the ascent of magma with enhanced KREEP concentrations.  相似文献   

17.
Abstract— Impact-induced comminution of planetary surfaces is pervasive throughout the solar system and occurs on submillimeter to global scales, resulting in comminution products that range from fine-grained surface soils, to massive, polymict ejecta deposits, to collisionally fragmented objects. Within this wide range of comminution products, we define regoliths in a narrow sense as materials that were processed by repetitive impacts to dimensional scales comparable to or smaller than that of component minerals of the progenitor rock(s). In this paper, we summarize a wide variety of impact experiments and other observations that were primarily intended to understand the evolution of regoliths on lunar basalt flows, and we discuss some of their implications for asteroidal surfaces. Cratering experiments in both rock and noncohesive materials, combined with photogeologic observations of the lunar surface, demonstrate that craters <500 m in diameter contribute most to the excavation of local bedrock for subsequent processing by micrometeorites. The overall excavation rate and, thus, growth rate of the debris layer decreases with time, because the increasingly thicker fragmental layer will prevent progressively larger projectiles from reaching bedrock. Typical growth rates for a 5 m thick lunar soil layer are initially (～≥3 Ga ago) a few mm/Ma and slowed to <1 mm/Ma at present. The coarse-grained crater ejecta are efficiently comminuted by collisional fragmentation processes, and the mean residence time of a 1 kg rock is typically 10 Ma. The actual comminution of either lithic or monomineralic detritus is highly mineral specific, with feldspar and mesostasis comminuting preferentially over pyroxene and olivine, thus resulting in mechanically fractionated fines, especially at grain sizes <20 μm. Such fractionated fines also participate preferentially in the shock melting of lunar soils, thus giving rise to “agglutinate” melts. As a consequence, agglutinate melts are systematically enriched in feldspar components relative to the bulk composition of their respective host soil(s). Compositionally homogeneous, impact derived glass beads in lunar soils seem to result from micrometeorite impacts on rock surfaces, reflecting lithic regolith components and associated mineral mixtures. Cumulatively, experimental and observational evidence from lunar mare soils suggests that regoliths derive substantially from the comminution of local bedrock; the addition of foreign, exotic components is not necessary to explain the modal and chemical compositions of diverse grain size fractions from typical lunar soils. Regoliths on asteroids are qualitatively different from those of the Moon. The modest impact velocities in the asteroid belt, some 5 km s?1, are barely sufficient to produce impact melts. Also, substantially more crater mass is being displaced on low-gravity asteroids compared to the Moon; collisional processing of surface boulders should therefore be more prominent in producing comminuted asteroid surfaces. These processes combine into asteroidal surface deposits that have suffered modest levels of shock metamorphism compared to the Moon. Impact melting does not seem to be a significant process under these conditions. However, the role of cometary particles encountering asteroid surfaces at presumably higher velocities has not been addressed in the past. Unfortunately, the asteroidal surface processes that seemingly modify the spectral properties of ordinary chondrites to match telescopically obtained spectra of S-type asteroids remain poorly understood at present, despite the extensive experimental and theoretical insights summarized in this report and our fairly mature understanding of lunar surface processes and regolith evolution.  相似文献   

18.
During impact events, zircons develop a wide range of shock metamorphic features that depend on the pressure and temperature conditions experienced by the zircon. These conditions vary with original distance from impact center and whether the zircon grains are incorporated into ejecta or remain within the target crust. We have employed the range of shock metamorphic features preserved in >4 Ga lunar zircons separated from Apollo 14 and 15 breccias and soils in order to gain insights into the impact shock histories of these areas of the Moon. We report microstructural characteristics of 31 zircons analyzed using electron beam methods including electron backscatter pattern (EBSP) and diffraction (EBSD). The major results of this survey are as follows. (1) The abundance of curviplanar features hosting secondary impact melt inclusions suggests that most of the zircons have experienced shock pressures between 3 and 20 GPa; (2) the scarcity of recrystallization or decomposition textures and the absence of the high‐pressure polymorph, reidite, suggests that few grains have been shocked to over 40 GPa or heated above 1000 °C in ejecta settings; (3) one grain exhibits narrow, arc‐shaped bands of twinned zircon, which map out as spherical shells, and represent a novel shock microstructure. Overall, most of the Apollo 14 and 15 zircons exhibit shock features similar to those of terrestrial zircon grains originating from continental crust below large (~200 km) impact craters (e.g., Vredefort impact basin), suggesting derivation from central uplifts or uplifted rims of large basins or craters on the Moon and not high‐temperature and ‐pressure ejecta deposits.  相似文献   

19.
Grooved and hilly terrains occur at the antipode of major basins on the Moon (Imbrium, Orientale) and Mercury (Caloris). Such terrains may represent extensive landslides and surface disruption produced by impact-generatedP-waves and antipodal convergence of surface waves. Order-of-magnitude calculations for an Imbrium-size impact (1034 erg) on the Moon indicateP-wave-induced surface displacements of 10 m at the basin antipode that would arrive prior to secondary ejecta. Comparable surface waves would arrive subsequent to secondary ejecta impacts beyond 103 km and would increase in magnitude as they converge at the antipode. Other seismically induced surface features include: subdued, furrowed crater walls produced by landslides and concomitant secondary impacts; emplacement and leveling of light plains units owing to seismically induced ‘fluidization’ of slide material; knobby, pitted terrain around old basins from enhancement of seismic waves in ancient ejecta blankets; and perhaps the production and enhancement of deep-seated fractures that led to the concentration of farside lunar maria in the Apollo-Ingenii region.  相似文献   

20.
We developed a seismometer system for a hard landing “penetrator” probe in the course of the former Japanese LUNAR-A project to deploy new seismic stations on the Moon. The penetrator seismometer system (PSS) consists of two short-period sensor components, a two-axis gimbal mechanism for orientation, and measurement electronics. To carry out seismic observations on the Moon using the penetrator, the seismometer system has to function properly in a lunar environment after a hard landing (impact acceleration of about 8000 G), and requires a signal-to-noise ratio to detect lunar seismic events. We evaluated whether the PSS could satisfactorily observe seismic events on the Moon by investigating the frequency response, noise level, and response to ground motion of our instrument in a simulated lunar environment after a simulated impact test. Our results indicate that the newly developed seismometer system can function properly after impact and is sensitive enough to detect seismic events on the Moon. Using this PSS, new seismic data from the Moon can be obtained during future lunar missions.  相似文献   

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