Small Impactor Research Articles

Constraints on gas giant satellite formation from the interior states of partially differentiated satellites

An icy satellite whose interior is composed of a homogeneous ice/rock mixture must avoid melting during its entire history, including during its formation when it was heated by deposition of accretional energy and short-lived radioisotopes. Estimates of the temperature rise associated with radiogenic and accretional heating, coupled with limits on satellite melting can be used to constrain the timing of formation of a partially differentiated satellite relative to the origin of the calcium–aluminum-rich inclusions (CAI's) as a function of its accretion timescale and the protosatellite disk temperature ( T d ). Geological characterization and spacecraft radio tracking data suggest that Callisto, the outermost regular satellite of Jupiter, and Saturn's mid-sized satellite Rhea, are partially differentiated if their interiors are in hydrostatic equilibrium. Because the specific conditions during the satellites' formation are uncertain, we determine accretional temperature profiles for a range of values for T d and accretion time scales with the limiting assumption that impactors deposit all their energy close to the surface, leading to maximally effective radiative cooling. We find that Callisto can remain unmelted during formation if it accreted on a time scale longer than 0.6 Myr. Considering both radiogenic and accretional heating, Callisto must have finished accreting no earlier than ∼4 Myr after formation of CAI's for T d = 100 K . Warmer disks or larger impactors that deposit their energy at depth in the satellite would require longer and/or later formation times. If Rhea accreted slowly (in 10 5 to 10 6 years), its growth must have finished no earlier than ∼2 Myr after CAI's for 70 K ⩽ T d ⩽ 250 K to avoid early melting. If Rhea formed quickly (⩽10 3 yr), its formation must have been delayed until at least 2 to 7 Myr after CAI's and in a disk with T d < 190 K in the small impactor limit. If the satellites form in slow-inflow-supplied disks as proposed by Canup and Ward [Canup, R.M., Ward, W.R., 2002. Astron. J. 124, 3404–3423], the implied satellite ages suggest that gas inflow to the giant planets ceased no earlier than ∼4 Myr after CAI's, comparable to average nebular lifetimes inferred from observations of circumstellar disks.

Micro-craters in aluminum foils: Implications for dust particles from comet Wild 2 on NASA's Stardust spacecraft

Dust impacts on aluminum foils during encounter of comet 81P/Wild 2 by the Stardust spacecraft in January 2004 have been simulated using spherical projectiles of monodispersive polymer, glass, and metals, and polydispersive mineral powders of diverse grain shapes. The encounter speed of the cometary particles was a constant and modest 6.1 km s �1 , well within the capabilities of light gas guns, permitting high fidelity experiments to infer dust size, density, and mass from quantitative dimensional analysis of both natural and experimental impact features. Specific interest focused on exceptionally small impactors, all <100 mm and some as small as 1.5 mm. To simulate the compound shape of many Stardust craters required novel, artificial aggregate projectiles of heterogeneous mass distribution. We demonstrate that the dimensional scaling obtained previously for millimeter sized impactors extends to particles as small as 10 mm at 6.1 km s �1 , all yielding a constant relationship for spherical soda lime glass projectiles of diameter (Dp) to crater diameter (Dc) in Al1100 of Dc ¼ 4.6 Dp; however, this ratio seems to decrease for projectiles � 10 mm. The overwhelming majority of the Stardust craters are <20 m mi n diameter, and substantial challenges remain in quantifying the exact size-frequency distribution of the Wild 2 comet dust. Nevertheless, the current experiments provide improved insights into some of the particles’ physical properties.

Higher-order dynamic response of composite sandwich panels with flexible core under simultaneous low-velocity impacts of multiple small masses

Small mass impactors, such as runway debris and hailstones may result in a wave controlled local response, which is essentially independent of boundary conditions. The higher-order impact model of sandwich beams presented by Mijia and Pizhong [Mijia, Y., Pizhong, Q., 2005. Higher-order impact modeling of sandwich structures with flexible core. International Journal of Solids and Structures 42 (10), 5460–5490] is developed and enhanced to impact analysis of sandwich panels with transversely flexible cores. Therefore, an improved fully dynamic higher-order impact theory is developed to analyze the low-velocity impact dynamic of a system which consists of a composite sandwich panel with transversely flexible core and multiple small impactors with small masses. Impacts are assumed to occur normally and simultaneously over the top face-sheet with arbitrary different masses and initial velocities of impactors. The contact forces between the panel and the impactors are treated as the internal forces of the system. First shear deformation theory (FSDT) is used for the face-sheets while three-dimensional elasticity is used for the soft core. The fully dynamic effects of the core layer and the face-sheets are considered in this study. Contact area can be varied with contact duration. The results in multiple mass impacts over sandwich panels that are hitherto not reported in the literature are presented based on proposed improved higher-order sandwich plate theory (IHSAPT). Finally, for the case study of the single mass impact, the numerical results of the analysis have been compared either with the available experimental results or with some theoretical results. As no literature could be found on the impact of multiple impactors over sandwich panels, the present formulation is validated indirectly by comparing the response of two cases of double small masses and single small mass impacts. Also, in order to demonstrate the applicability of the validation, the analytical relation of minimum distance between two impactors is derived based on Olsson’s wave control principle in this paper.

Influences of atmospheric variations on Mars's record of small craters

Planetary atmospheres influence cratering rates at small diameters (∼2–250 m) by filtering impactor populations via ablation, aerobraking and breakup of entering objects. The atmosphere of Mars undergoes rapid and drastic obliquity-driven variations in density, corresponding to pressure variations between zero and several tens of millibars. Here a simulation is used to assess the fate of a large population of impactors interacting with the present and predicted past and future martian atmospheres. We find that even Mars's present atmosphere significantly reduces crater production rates at small diameters (<30 m) and past denser atmospheres would have affected cratering even more strongly, and to considerably larger diameters. These effects are increased if the inner Solar System's small impactor population contains significant numbers of icy, cometary bodies. Evidence of recent atmospheric density variations may be detectable in the martian small cratering record with future planned imaging capabilities. Because of martian atmospheric effects and variations, surface ages derived from counts of craters of less than about 250 m on Mars may be underestimated.

KBO binaries: how numerous were they?

Given the large orbital separation and high satellite-to-primary mass ratio of all known Kuiper Belt Object (KBO) binaries, it is important to reassess their stability as bound pairs with respect to several disruptive mechanisms. Beside the classical shattering and dispersing of the secondary due to a high-velocity impact, we consider the possibility that the secondary is kicked off its orbit by a direct collision of a small impactor, or that it is gravitationally perturbed due to the close approach of a somewhat larger TNO. Depending on the values for the size/mass/separation of the binaries that we used, 2 or 3 of the 9 pairs can be dispersed in a timescale shorter than the age of the Solar System in the current rarefied environment. A contemporary formation scenario could explain why we still observe these binaries, but no convincing mechanism has been proposed to date. The primordial formation scenarios, which seem to be the only viable ones, must be revised to increase the formation efficiency in order to account for this high dispersal rate. For the reference current KBO population, objects like the large-separation KBO binaries 1998 WW 31 or 2001 QW 322 must have been initially an order of magnitude more numerous. If the KBO binaries are indeed primordial, then we show that the mass depletion of the Kuiper belt cannot result from collisional grinding, but must rather be due to dynamical ejection.

Cratering rates in the outer Solar System

This paper is a compilation by table, graph, and equation of impact cratering rates from Jupiter to Pluto. We use several independent constraints on the number of ecliptic comets. Together they imply that the impact rate on Jupiter by 1.5-km-diameter comets is currently Ṅ( d > 1.5 km) = 0.005−0.003+0.006 per annum. Other kinds of impactors are currently unimportant on most worlds at most sizes. The size–number distribution of impactors smaller than 20 km is inferred from size–number distributions of impact craters on Europa, Ganymede, and Triton; while the size–number distribution of impacting bodies larger than 50 km is equated to the size–number distribution of Kuiper Belt objects. The gap is bridged by interpolation. It is notable that small craters on Jupiter’s moons indicate a pronounced paucity of small impactors, while small craters on Triton imply a collisional population rich in small bodies. However it is unclear whether the craters on Triton are of heliocentric or planetocentric origin. We therefore consider two cases for Saturn and beyond: a Case A in which the size–number distribution is like that inferred at Jupiter, and a Case B in which small objects obey a more nearly collisional distribution. Known craters on saturnian and uranian satellites are consistent with either case, although surface ages are much younger in Case B, especially at Saturn and Uranus. At Neptune and especially at Saturn our cratering rates are much higher than rates estimated by Shoemaker and colleagues, presumably because Shoemaker’s estimates mostly predate discovery of the Kuiper Belt. We also estimate collisional disruption rates of moons and compare these to estimates in the literature.

Laboratory Measurements of the Performance of Pesticide Filters for Agricultural Vehicle Cabs against Sprays and Vapours

Pesticide filters for use in agricultural vehicle cabs contain a vapour filter element, sometimes with a particulate filter element upstream. The former normally comprises a granular carbon filter and the latter a pleated paper or electrostatic fibrous filter. Pesticides are normally applied to crops in the form of sprays but a certain amount of vapour is always present in any spray of a volatile compound. The efficiency of a number of fibrous filters used in tractor cabs has been measured against droplets of spray designed to resemble pesticide spray to which the vehicle might be exposed during crop or orchard spraying. The evaporation of pesticide vapour from captured droplets and its subsequent capture by activated carbon filters has also been investigated. In the first experiments, carried out in a medium-sized test tunnel, a tracer of strontium chloride in dilute solution was used, along with a nozzle of the sort used in practice. Samples were collected before and after the filters using small eight-stage cascade impactors. The performance of the filters with respect to the sprays followed the same pattern as that previously observed with solid particles of the same size. Pleated paper filters were of low efficiency, whereas specimens of both glass fibre filters and electrically charged filters performed well. The performance of a scaled down particulate/vapour filter was measured using real pesticides. A finite amount of evaporation from droplets on the particulate filter was observed and was related, albeit imperfectly, to the vapour pressure of the pesticide. Evaporation did not increase consistently with temperature, possibly because of decomposition of the pesticide. The efficiency of commercially available carbon filters for capture of vapour was found to be about 90%, but it is not certain whether the penetration of vapour was due to failure of the filter to capture it or to leakage.

Atmospheric Disturbances and Radiation Impulses Caused by Large-Meteoroid Impacts on the Surface of Mars. II. Radiation Impulse Characteristics and Parameters of the Warm Layer

This paper presents the results of the calculation of spectral and angular characteristics of radiation emitted by the disturbed region after the vertical impacts on the Martian surface of stony meteoroids with radii R0 from 1 to 100 m at speeds of 11–20 km/s. The time dependences are given for the density of the radiation flux incident on horizontal surface areas located at different distances from the impact point. For small impactors (R0= 1 m), the heating of the surface and surrounding gas by the radiation impulse from the hot region formed after the impact is insignificant even at the crater edge. However, the radiation impulse that heats up the surface is also emitted during the meteoroid flight through the atmosphere. Although this heating is insufficient to initiate evaporation, heat transfer by turbulent diffusion leads to the formation of a layer with temperatures that substantially exceed the initial temperature of the atmosphere. For large impactors (R0 = 100 m), the total specific impulse of the plume radiation gives rise to the emergence of the heated layer with a thickness on the order of several meters within several kilometers of the impact point. The formation of this “warm” layer may lead to the formation of a high-speed jet moving along the Martian surface as well as eddies at the front of the precursor with a subsequent intense rise of dust.

Particle collection efficiency of small inertial impactors considering particle gravitational effect

Particle collection efficiency of small inertial impactors considering particle gravitational effect

High-Resolution Calculations of Asteroid Impacts into the Venusian Atmosphere

We present results from a number of 2D high-resolution hydrodynamical simulations of asteroids striking the atmosphere of Venus. These cover a wide range of impact parameters (velocity, size, and incidence angle), but the focus is on 2–3 km diameter asteroids, as these are responsible for most of the impact craters on Venus. Asteroids in this size range are disintegrated, ablated, and significantly decelerated by the atmosphere, yet they retain enough impetus to make large craters when they meet the surface. We find that smaller impactors (diameter <1–2 km) are better described by a “pancaking” model in which the impactor is compressed and distorted, while for larger impactors (>2–3 km) fragmentation by mechanical ablation is preferred. The pancaking model has been modified to take into account effects of hydrodynamical instabilities. The general observation that most larger impactors disintegrate by shedding fragments generated from hydrodynamic instabilities spurs us to develop a simple heuristic model of the mechanical ablation of fragments based on the growth rates of Rayleigh–Taylor instabilities. Although in principle the model has many free parameters, most of these have little effect provided that they are chosen reasonably. In practice the range of model behavior can be described with one free parameter. The resulting model reproduces the mass and momentum fluxes rather well, doing so with reasonable values of all physical parameters.

Sample return from small solar system bodies

With plans for multiple sample return missions in the next decade, NASA requested guidance from the National Research Council's SSB on how to treat samples returned from solar system bodies such as planetary satellites, asteroids and comets. A special Task Group assessed the potential for a living entity to be included in return samples from various bodies as well as the potential for large scale effects if such an entity were inadvertently introduced into the Earth's biosphere. The Group also assessed differences among solar system bodies, identified investigations that could reduce uncertainty about the bodies, and considered risks of returned samples compared to natural influx of material to the Earth in the form of interplanetary dust particles, meteorites and other small impactors. The final report (NRC, 1998) provides a decision making framework for future missions and makes recommendations on how to handle samples from different planetary satellites and primitive solar system bodies.

Flash heating on the early Earth.

It has been suggested that very large impact events (approximately 500 km diameter impactors) sterilized the surface of the young Earth by producing enough rock vapor to boil the oceans. Here, we consider surface heating due to smaller impactors, and demonstrate that surface temperatures conductive to organic synthesis resulted. In particular, we focus on the synthesis of thermal peptides. Previously, laboratory experiments have demonstrated that dry heating a mixture of amino acids containing excess Asp, Glu, or Lys to temperatures approximately 170 degrees C for approximately 2 hours yields polypeptides. It has been argued that such temperature conditions would not have been available on the early Earth. Here we demonstrate, by analogy with the K/T impact, that the requisite temperatures are achieved on sand surfaces during the atmospheric reentry of fine ejecta particles produced by impacts of bolides approximately 10-20 km in diameter, assuming approximately 1-100 PAL CO2. Impactors of this size struck the Earth with a frequency of approximately 1 per 10(4)-10(5) y at 4.2 Ga. Smaller bolides produced negligible global surface heating, whereas bolides > 30 km in diameter yielded solid surface temperatures > 1000 K, high enough to pyrolyze amino acids and other organic compounds. Thus, peptide formation would have occurred globally for a relatively narrow range of bolide sizes.

Damage from the impacts of small asteroids

Previous work is extended by using a model spherical atmosphere with a fitted density profile to find the damage done by an asteroid entering it at various zenith angles. At zenith angle 0° and a typical impact: velocity at the top of the atmosphere of V = 17.5 km s −1, the atmosphere absorbs more than half the kinetic energy of stony meteoroids with diameters, D M<230 m and iron meteoroids with D M<50 m. At zenith angle 45° the corresponding figures are 360 and 70 m while at 60° they are 500 and 100 m. For comets with V = 50 km s −1 the values are D M<1900 and 3000 m for 45 and 60°, respectively, using typical values of ablation, but they are much smaller if ablation is reduced. Only impactors with D M above these critical values are effective in producing ground impact damage: craters, earthquakes, and tsunami. Smaller impactors can still produce atmospheric blast waves. It is found that the area of destruction around the impact point in which the overpressure in the blast wave exceeds 4p.s.i. = 2.8 × 10 5 dyn cm −2, which is enough to knock over trees and destroy buildings. It is found that for chondritic asteroids entering at zenith angle 45° and an impact velocity at the top of the atmosphere of 17.5 km s −1 that it increases rapidly from zero for those less than 50 m in diameter (13.5 megatons) to about 2000 km 2 for those 76 m in diameter (31 megatons). If we assume that a stony asteroid 100 m in diameter hits land about every 1000 years, we find that a 50 m diameter one (causing some blast damage) hits land every 125 years while a Tunguska size impactor occurs about every 400 years. If iron asteroids are about 3.5 per cent of the frequency of stony ones of the same size, they constitute most of the impactors that produce areas of blast damage of less than 300 km 2. While the optical flux from a small asteroid such as Tunguska is enough to ignite pine forests, the blast from it goes beyond the radius within which the fire starts. The blast tends to blow out the fire, so it is likely that the impact will char the forest (as at Tunguska), but it will not produce a sustained fire.

On the mechanical behaviour of pultruded sections submitted to low-velocity impact

An experimental investigation has been carried out to study the dynamic behaviour of composite profiles made by pultrusion. Two different types of glass/polyester pultruded beams were subjected to low-velocity impact loading with several incident kinetic energy ranges. The resulting data from the drop-weight tests provide specific information about the effect of the impactor velocity, the impactor mass and the impactor nose radius, all of which have a great influence on the impact response of these profiles. A big-impactor (BI) strike produces less delamination than a small-impactor (SI) one. It appears that damage localisation has a great influence on the mechanical response of these profiles. An experimental study of the sequence of damage mechanisms during impact loading is also carried out. A methodology based on combined accelerometer/strain-gauge signal analysis is performed to identify the damage sequence which occurs over the impact duration. The post-impact vibration has a notable influence on the internal damage growth (cracking and delamination). The proposed damage sequence is strongly supported by an experimental deductive method.

An impact plume model for atmospheric holes in the FUV dayglow

A transient decrease in FUV dayglow emission from a ∼ 10³ km² region of Earth's upper atmosphere is one expected outcome of the collision of a stony meteoroid as small as 50 cm in diameter. Computational models of the entry of projectiles between 210 and 21,000 kg predict the ejection of low‐density plumes of air from the stratosphere and mesosphere at velocities of up to 5 km/s. The plumes reach an altitude of over 1000 km, displacing the atomic O‐rich thermosphere, and replacing it with photoelectron‐ and O‐poor air from beneath 80 km. The FUV dayglow is normally dominated by O emissions so the plume appears as a dark spot when viewed from above. FUV dayglow holes are reported at rates ∼ 104–106 larger than the impact flux of objects in the size range modeled here, suggesting either 1) the observed rate is greatly overestimated, 2) there is an additional mechanism, or 3) much smaller impactors (which we have not modeled) can also generate FUV darkening plumes.

Dimensionality scaled penetration experiments: Aluminum targets and glass projectiles 50 μm to 3.2 MM in diameter

Summary Spherical soda-lime glass projectiles 50, 150, 1000 and 3175 μm in diameter (Dp) in aluminum targets (series 1100; “annealed”) of variable thickness T, were used to determine how the penetration-hole diameter (Dh) varied as a function of Dp/T at a constant impact velocity of 6 km/s. The target thickness ranged from infinite half-space geometries to 0.8 μm thick foils. Virtually identical morphologies characterize the penetration holes, no matter what projectile size, at equivalent Dp/T conditions. The relative hole diameter (Dh/Dp) decreases systematically with increasing Dp/T from Dh ≅ 4Dp for massive targets, to Dh = Dp for very thin foils. A modest dependence on the absolute projectile size is observed; comparatively small cracters, yet relatively large penetration holes are produced by the smallest (50 μm) impactors. Nevertheless, linear dimensional scaling seems suitable for first-order estimates of Dp from the measurement of Dh and T on space-exposed surfaces. The projectile fragments and the debris dislodged from the target were intercepted by witness plates that were located behind the target. The dispersion angle of this debris cloud depends on the thickness of the target. In addition, millimeter-sized impactors are collisionally fragmented with greater ease than small impactors. Furthermore, we observe that systematic changes in the specific energy of dislodged projectile and target material occur as a function of Dp/T. While linear scaling of target and projectile dimensions is a useful framework to explain many observations and associated shock processes, we suggest that consideration of the absolute and relative shock-pulse duration in the projectile (tp) and target (tt) may ultimately be the more useful approach. It implicitly accounts for all dimensions and, additionally, for specific impact velocities and pertinent material properties, via equations-of-state, for the impacting pair.

Determining the effects of space debris impacts on spacecraft structures

The collision hazard to space systems from trackable orbital debris has doubled over the last 15 years in some regions of low Earth orbit. Yet the hazard from nontrackable debris may be even more severe in some Earth orbits. Thousands of orbiting objects too small to be tracked reliably may damage or destroy space hardware via hypervelocity collision, resulting in mission degradation or termination and generated debris. An understanding of the modes by which a small impactor collides and interacts with a massive complex structure is required to: (1) accurately determine the present debris environment, (2) quantify the operational lifetime of satellites, and (3) predict the future environment. The Defense Nuclear Agency has initiated the DoD Spacecraft Breakup Modeling Program to improve the accuracy and usefulness of satellite breakup models, with an emphasis on collision-induced events. The breakup modeling approach fits into three broad categories: empirical, semianalytic, and complex. This model development effort is being conducted in parallel with an experimental HyperVelocity Impact (HVI) test program to produce accurate data required to develop and validate the breakup models. Current results from the breakup modeling effort are presented and discussed, along with data from the associated HVI impact test program.

CAMPEDS--a dust sampling and assessment system for use in hard rock mines.

A dust sampling system comprising gravimetric assessment by weighing and quartz assessment by X-ray diffraction, as developed by the Elliot Lake Laboratory for use in hard rock mines, is described. The compromises made between the sometimes conflicting requirements of sampling, ashing, weighing, quartz assessment and pump performance are stressed. Emphasis is given to the need for defining the total dust sampling and analysis system, including the calibration procedures. The system incorporates: (1) a small impactor size selector and integral cassette filter holder, mounted with the pump on the miner's cap lamp battery; (2) a silver membrane filter 25 mm in diameter; (3) gravimetric assessment before and after ashing; (4) X-ray diffraction assessment for quartz; (5) computer controlled diffractometer. Alternatives are available for lapel sampling or, using a pump driven by a light-weight battery, fixed station sampling or personal sampling on surface. Size-selection is calibrated, by comparison with a reference sampler, while quartz calibration is by collection of samples in a pure quartz airborne dust cloud. The advantages of the system are: rapid assessment of quartz, with low requirements for technician time and skill; high throughput capacity—10 000 samples per year per X-ray diffractometer; easy logistics for personal sampling in underground mines; robust sampler and samples; high resistance to contamination of respirable dust by coarse dust.

Failure modes of InGaAsP/InP lasers due to adhesives : Mitsuo Fukuda, Osamu Fujita and Genzo Iwane. IEEE Trans. Components Hybrids Mfg Technol.CHMT-7 (2), 202 (1984)

Prominent macroscopic sedimentary laminations, consisting of mm- to cm-thick alternating well-sorted but poorly mixed silicate and metal-rich layers cut by faults and downward penetrating load structures, are prevalent in the Isheyevo (CH/CBb) carbonaceous chondrite. The load structures give the up direction of this sedimentary rock that accumulated from in-falling metal- and silicate-rich grains under near vacuum conditions onto the surface of an accreting planetesimal. The Isheyevo meteorite is the end result of a combination of events and processes that we suggest was initiated by the glancing blow impact of two planetesimals. The smaller impactor was disrupted forming an impact plume downrange of the impact. The components within the plume were aerodynamically size sorted by the nebular gas and swept up by the impacted planetesimal before turbulent mixing within the plume could blur the effects of the sorting. This plume would have contained a range of materials including elementally zoned Fe-Ni metal grains that condensed in the plume to disrupted unaltered material from the crust of the impactor, such as the hydrated matrix lumps. The juxtaposition of hydrated matrix lumps, some of which have not been heated above 150°C, together with components that formed above 1000°C, is compelling evidence that they were swept up together. Sweep-up would have occurred as the rotating impactor moved through the plume producing layers of material: the Isheyevo sample thus represents material accumulated while that part of the rotating planetesimal moved into the plume. Vibrations from subsequent impacts helped to form the load structures and induced weak grading within the layers via kinetic sieving. Following sweep-up, the particles were compacted under low static temperatures as evidenced by the preservation of elementally zoned Fe-Ni metal grains with preserved martensite α2 cores, distinct metal-metal grain boundaries, and metal-deformation microstructures. This meteorite provides evidence of gentle layer-by-layer accretion in the early Solar System, and also extends the terrestrial sedimentary source-to-sink paradigm to a near vacuum environment where neither fluvial nor aeolian processes operate.

Reliability of gate metallization in power GaAs MESFETS : K. Katsukawa, Y. Kose, M. Kanomori and S. Sando. Proc. IEEE Reliab. Phys. Conf. 59 (1984)

Prominent macroscopic sedimentary laminations, consisting of mm- to cm-thick alternating well-sorted but poorly mixed silicate and metal-rich layers cut by faults and downward penetrating load structures, are prevalent in the Isheyevo (CH/CBb) carbonaceous chondrite. The load structures give the up direction of this sedimentary rock that accumulated from in-falling metal- and silicate-rich grains under near vacuum conditions onto the surface of an accreting planetesimal. The Isheyevo meteorite is the end result of a combination of events and processes that we suggest was initiated by the glancing blow impact of two planetesimals. The smaller impactor was disrupted forming an impact plume downrange of the impact. The components within the plume were aerodynamically size sorted by the nebular gas and swept up by the impacted planetesimal before turbulent mixing within the plume could blur the effects of the sorting. This plume would have contained a range of materials including elementally zoned Fe-Ni metal grains that condensed in the plume to disrupted unaltered material from the crust of the impactor, such as the hydrated matrix lumps. The juxtaposition of hydrated matrix lumps, some of which have not been heated above 150°C, together with components that formed above 1000°C, is compelling evidence that they were swept up together. Sweep-up would have occurred as the rotating impactor moved through the plume producing layers of material: the Isheyevo sample thus represents material accumulated while that part of the rotating planetesimal moved into the plume. Vibrations from subsequent impacts helped to form the load structures and induced weak grading within the layers via kinetic sieving. Following sweep-up, the particles were compacted under low static temperatures as evidenced by the preservation of elementally zoned Fe-Ni metal grains with preserved martensite α2 cores, distinct metal-metal grain boundaries, and metal-deformation microstructures. This meteorite provides evidence of gentle layer-by-layer accretion in the early Solar System, and also extends the terrestrial sedimentary source-to-sink paradigm to a near vacuum environment where neither fluvial nor aeolian processes operate.