Laboratory impact experiments with decimeter-to meter-scale targets to measure momentum enhancement

Durda, D. D.; Walker, James D.; Chocron, Sidney; Housen, K. R.; Grosch, Donald J.; Marchi, S.; Flynn, G. J.; Strait, M. M.

doi:10.1016/j.pss.2019.07.008

Cited by 9 publications

(6 citation statements)

References 23 publications

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“…Our result for 𝛽 is consistent with numerical simulations [11][12][13][14][15][16][17][18][19][20][21] and laboratory experiments [22][23][24][25][26][27][28] of kinetic impacts, which have consistently indicated that 𝛽 is expected to fall between about 1 and 6. However, non-unique combinations of asteroid mechanical properties (e.g., cohesive 5 strength, porosity, and friction angle) can produce similar values of 𝛽 in impact simulations 18 .…”

supporting

confidence: 89%

Momentum Transfer from the DART Mission Kinetic Impact on Asteroid Dimorphos

Cheng

Agrusa

Barbee³

et al. 2022

Preprint

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The NASA Double Asteroid Redirection Test (DART) mission performed a kinetic impact on asteroid Dimorphos, the satellite of the binary asteroid (65803) Didymos, at 23:14 UTC on September 26, 2022 as a planetary defense test1. DART was the first hypervelocity impact experiment on an asteroid at size and velocity scales relevant to planetary defense, intended to validate kinetic impact as a means of asteroid deflection. Here we report the first determination of the momentum transferred to an asteroid by kinetic impact. Based on the change in the binary orbit period2, we find an instantaneous reduction in Dimorphos’s along-track orbital velocity component of 2.70 ± 0.10 mm s–1, indicating enhanced momentum transfer due to recoil from ejecta streams produced by the impact3,4. For a Dimorphos bulk density range of 1,500 to 3,300 kg m–3, we find that the expected value of the momentum enhancement factor, β, ranges between 2.2 and 4.9, depending on the mass of Dimorphos. If Dimorphos and Didymos are assumed to have equal densities of 2,400 kg m–3, 〖β=3.61〗_(-0.25)^(+0.19) (1σ). These β values indicate that significantly more momentum was transferred to Dimorphos from the escaping impact ejecta than was incident with DART. Therefore, the DART kinetic impact was highly effective in deflecting the asteroid Dimorphos.

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supporting

confidence: 89%

Momentum Transfer from the DART Mission Kinetic Impact on Asteroid Dimorphos

Cheng

Agrusa

Barbee³

et al. 2022

Preprint

Self Cite

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“…This scenario differs in three regards: (i) DART's impact speed is much larger than the impact speeds in the laboratory experiments, (ii) the experiment is conducted under Earth's gravity, while the DART impact takes place in a low-gravity environment, and (iii) DART's mass is seven orders of magnitude larger than the projectile in the experiments. Previous studies have shown that the momentum enhancement depends on such scale effects (Holsapple & Housen 2012;Housen & Holsapple 2015;Walker et al 2013;Jutzi & Michel 2014;Walker & Chocron 2015;Durda et al 2019;Schimmerohn et al 2019;Chourey et al 2020). To bridge the gap between the different regimes and study the effect on crater size and momentum enhancement, we conducted additional simulations with iSALE, where we (i) increased the velocity up to 7 km s −1 based on the laboratory setup, but kept the impactor mass the same as in the experiment, and (ii) decreased gravity to 5e-5 m s −2 (Table 3 and Figure 5).…”

Section: From Laboratory Scale To the Dart Scalementioning

confidence: 99%

Momentum Enhancement during Kinetic Impacts in the Low-intermediate-strength Regime: Benchmarking and Validation of Impact Shock Physics Codes

et al. 2022

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In 2022 September, the DART spacecraft (NASA’s contribution to the Asteroid Impact & Deflection Assessment (AIDA) collaboration) will impact the asteroid Dimorphos, the secondary in the Didymos system. The crater formation and material ejection will affect the orbital period. In 2027, Hera (ESA’s contribution to AIDA) will investigate the system, observe the crater caused by DART, and characterize Dimorphos. Before Hera’s arrival, the target properties will not be well-constrained. The relationships between observed orbital change and specific target properties are not unique, but Hera’s observations will add additional constraints for the analysis of the impact event, which will narrow the range of feasible target properties. In this study, we use three different shock physics codes to simulate momentum transfer from impactor to target and investigate the agreement between the results from the codes for well-defined target materials. In contrast to previous studies, care is taken to use consistent crushing behavior (e.g., distension as a function of pressure) for a given porosity for all codes. First, we validate the codes against impact experiments into a regolith simulant. Second, we benchmark the codes at the DART impact scale for a range of target material parameters (10%–50% porosity, 1.4–100 kPa cohesion). Aligning the crushing behavior improves the consistency of the derived momentum enhancement between the three codes to within +/−5% for most materials used. Based on the derived mass–velocity distributions from all three codes, we derive scaling parameters that can be used for studies of the ejecta curtain.

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“…These thermocouples were used to determine when the targets reached equilibrium temperature. In run #1, we hung the targets in the vacuum chamber with two wires to allow measurements of target recoil (Durda et al, 2019). During handling, the targets were positioned on a cooled foam support to limit heating.…”

Section: Target Temperaturementioning

confidence: 99%

“…In runs #2 and #3, impacts were perpendicular to the sample's surface (90°, or head-on), except for two test cases at 30°(Table 1). The main purpose of the non head-on impacts was to measure impact momentum enhancement (for details see Durda et al, 2019).…”

Section: Projectile Speed Size and Anglementioning

confidence: 99%

Hypervelocity Impact Experiments in Iron‐Nickel Ingots and Iron Meteorites: Implications for the NASA Psyche Mission

et al. 2020

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The National Aeronautics and Space Administration (NASA) Psyche mission will visit the 226‐km diameter main belt asteroid (16) Psyche, our first opportunity to visit a metal‐rich object at close range. The unique and poorly understood nature of Psyche offers a challenge to the mission as we have little understanding of the surface morphology and composition. It is commonly accepted that the main evolutionary process for asteroid surfaces is impact cratering. While a considerable body of literature is available on collisions on rocky/icy objects, less work is available for metallic targets with compositions relevant to Psyche. Here we present a suite of impact experiments performed at the NASA Ames Vertical Gun Range facility on several types of iron meteorites and foundry‐cast ingots that have similar Fe‐Ni compositions as the iron meteorites. Our experiments were designed to better understand crater formation (e.g., size, depth), over a range of impact conditions, including target temperature and composition. We find that the target strength, as inferred from crater sizes, ranges from 700 to 1,300 MPa. Target temperature has measurable effects on strength, with cooled targets typically 10–20% stronger. Crater morphologies are characterized by sharp, raised rims and deep cavities. Further, we derive broad implications for Psyche's collisional evolution, in light of available low resolution shape models. We find that the number of large craters (>50 km) is particularly diagnostic for the overall bulk strength of Psyche. If confirmed, the number of putative large craters may indicate that Psyche's bulk strength is significantly reduced compared to that of intact iron meteorites.

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Laboratory impact experiments with decimeter-to meter-scale targets to measure momentum enhancement

Cited by 9 publications

References 23 publications

Momentum Transfer from the DART Mission Kinetic Impact on Asteroid Dimorphos

Momentum Transfer from the DART Mission Kinetic Impact on Asteroid Dimorphos

Momentum Enhancement during Kinetic Impacts in the Low-intermediate-strength Regime: Benchmarking and Validation of Impact Shock Physics Codes

Hypervelocity Impact Experiments in Iron‐Nickel Ingots and Iron Meteorites: Implications for the NASA Psyche Mission

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