Presentation Information
[PPS05-P02]Oblique Impacts on Granular Surfaces in Low Gravity: Development of an Experimental System II
*Akiko Nakamura1, Ryosei Waki5, Tetsushi Sakurai1, Sunao Hasegawa2, Masato Kiuchi3, Takaya Okamoto4, Koji Wada4 (1.Graduate School of Science, Kobe University, 2.Japan Aerospace Exploration Agency, 3.Ritsumeikan University, 4.Planetary Exploration Research Center, Chiba Institute of Technology, 5.Faculty of Science, Kobe University)
Keywords:
Impact,Crater,small body,regolith
In low-gravity environments on the surfaces of small bodies, interparticle forces within regolith, such as cohesion, may influence the crater formation process. Oblique impacts are also common in natural impact events on planetary surfaces. In this study, we developed an experimental system to observe the growth of craters formed by oblique impacts under reduced-gravity conditions.
A nylon cylindrical projectile (4.3 mm in diameter, 4.3 mm in height, and 0.074 g in mass) was launched at a velocity of approximately 1.6 km/s with an incidence angle of 15° relative to the target surface. As a regolith simulant, irregularly shaped iron particles several hundred micrometers in size, with a bulk density of 4.9 g/cm³, were used to prevent the resulting crater from becoming excessively large relative to the container size.
The container holding the target material was allowed to fall along a guide frame installed inside a chamber. During the fall, a light sensor triggered the projectile launch. The projectile flight was recorded from the side, while the crater growth on the target surface was observed from above via a mirror mounted at the chamber window, using high-speed cameras.
The simulated gravitational acceleration achieved in this experiment was 0.74 m/s² (0.076 G). A comparison of the time evolution of crater dimensions in both the projectile trajectory direction and the perpendicular direction under 1 G and reduced-gravity conditions indicates that the results can be consistently scaled by √(D/g).
A nylon cylindrical projectile (4.3 mm in diameter, 4.3 mm in height, and 0.074 g in mass) was launched at a velocity of approximately 1.6 km/s with an incidence angle of 15° relative to the target surface. As a regolith simulant, irregularly shaped iron particles several hundred micrometers in size, with a bulk density of 4.9 g/cm³, were used to prevent the resulting crater from becoming excessively large relative to the container size.
The container holding the target material was allowed to fall along a guide frame installed inside a chamber. During the fall, a light sensor triggered the projectile launch. The projectile flight was recorded from the side, while the crater growth on the target surface was observed from above via a mirror mounted at the chamber window, using high-speed cameras.
The simulated gravitational acceleration achieved in this experiment was 0.74 m/s² (0.076 G). A comparison of the time evolution of crater dimensions in both the projectile trajectory direction and the perpendicular direction under 1 G and reduced-gravity conditions indicates that the results can be consistently scaled by √(D/g).